transforming lives - Institute of Physics [PDF]

0 downloads 334 Views 2MB Size Report
Jun 9, 2013 - to the outside of laptop bags, enabling the bag to recharge smaller ... Samsung, for example, ... June 2013 Physics: transforming lives I17.
Case studies prepared by IOP in partnership with EPSRC and STFC | June 2013

Physics: transforming lives

The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application. We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.


There are many ways of describing the beauty and elegance of physics and the incredible value that it has delivered for society, everpresent in the everyday things around us. Physics continues to help us unlock the mysteries of our universe and the world we live in, and is one of our most powerful enablers of innovation and discovery. Physics research explores and expands the boundaries of our knowledge. In July 2012, researchers at the Large Hadron Collider at CERN moved us one step closer to unlocking the mysteries of what our universe is made of when they announced the discovery of a Higgs boson – thought to be responsible for giving mass to everything in our universe. But physics is also central to everyday life. Physicists are actively collaborating with other researchers and applying their knowledge and technical skills in response to the major challenges of our time, such as sustainable sources of future energy, understanding our changing climate and global food security. Their efforts can also be found at the heart of the technologies we use each day, such as computers, smartphones and GPS devices, which would not exist without physics research. Physics also helps improve the quality of our lives through the use of high-tech equipment, such as particle accelerators, which find important application in healthcare, playing such a key role in improving the diagnosis and treatment of diseases like cancer. At the Institute of Physics, one of our objectives is to promote the fundamental importance of the discipline by showcasing how advances made by physicists in both academia and industry continue to impact upon all our lives. Physics: transforming lives is a series of short case studies reviewing how innovations as powerful as magnetic-resonance imaging, have emerged from studies in basic physics and become routine technologies. The booklet also provides some clues as to how things may develop over the next few years, coupled with numerous facts and figures which will be useful to Government and in the classroom. Professor Paul Hardaker Chief Executive The Institute of Physics

June 2013 Physics: transforming lives



The space industry Liquid-crystal displays Plastic electronics Radio-frequency identification tags Optical fibres Cancer treatment Physics and DNA Energy efficiency Detecting explosives and pollutants Data storage Satellite timing and navigation

5 9 13 19 23 29 39 45 51 55 59

June 2013 Physics: transforming lives


Physicists are actively engaged in helping to solve everyday problems by working collaboratively with other researchers and applying their knowledge and technical skills in response to the major challenges of our time, such as environmental change brought about by our soaring demand for energy from finite resources. Their efforts can be found in everyday technology, such as smartphones and GPS devices, which would not exist today without physics research.

4 I IOP Institute of Physics

The space industry

A vibrant space economy enables satellites to provide a welcome boost during a downturn.

The science Almost the entire UK space industry stems from physics research, which underpins everything from the design of the satellites to the trajectory at which rockets are launched, to the tweaks that must be made to keep satellites in orbit and pointing in the right direction. Spacecraft orbiting the Earth – or en route to their designed orbit – must traverse a region that is awash with charged particles that can damage the sensitive electronics mounted on satellites. Physicists must develop materials that are inured to this harsh environment in order to keep satellites functioning for months and years. Satellites also need electrical power to function, and physicists devise ever cleverer ways to harness the Sun’s rays for this purpose – although fuel cells and nuclear power have also been used. Rocket science The Harwell Oxford Space Cluster is the national innovation hub for space technology and new satellite applications and services. The hub was founded on STFC’s capabilities in its Rutherford Appleton Laboratory (RAL) Space department and now includes the European Space Agency’s UK office, their Business Incubation Centre, and the Satellite Applications Catapult Centre, which is supported by the Technology Strategy Board. What physics does it rely on? −− Classical mechanics −− Materials science −− Magnetohydrodynamics −− Condensed-matter physics Impact The space industry has prospered in recent times despite the nation’s limited finances. Over the past decade it has grown to become a medium-sized industry in the UK, directly employing 30,000 people and reporting a turnover of £9.1 bn in the year 2010/11. The vast majority of this turnover, 89% or £8.2 bn, comes from the industry’s downstream sector; for example, satellite communications, satellite broadcasting, satellite-navigation, and the like. Since 2008/09, the space industry has grown by 15.6%, an average annual growth rate of 7.5%.

June 2013 Physics: transforming lives


The space industry

Applications Over the past few decades, the space industry has helped to spur globalisation by cutting the cost of communication and enabling ease of contact. Satellites have revolutionised telecommunications, broadcasting and internet access, all of which have increased overall productivity. Demand for ubiquitous access to social networking is creating new opportunities for satellite broadcasting and communications. Other applications include the provision of satellite-navigation systems to vehicle drivers, and communications technologies to the military. Broadcasting In the UK satellite broadcasting makes up the largest proportion of the turnover generated by the space industry’s dominant downstream sector, about 70% between 2008/09 and 2010/11. Through this share of the downstream sector, satellite broadcasting generated a turnover of about £5.8 bn in 2010/11. More than a third of homes in the UK now have satellite television feeds. Satellite broadcasting is cheaper to deliver to remote areas than cable, and reaches places that terrestrial broadcasting would struggle to serve. Not only is satellite television popular with subscribers, it is also used by broadcasters: almost all television goes via a satellite at least once on its way to homes, whether or not the viewer is explicitly paying for satellite television or not. Communications and geopositioning Satellite communications, including telephony between remote locations, satellite-navigation systems, air traffic control systems and communications to ships, account for 13% of the revenue generated by the UK space industry. Satellites enable people to communicate over long distances where terrestrial broadcasting or a direct cable connection are impractical. Satellites cover a far greater area than terrestrial systems and enable higher bandwidths to be used, so that hundreds of thousands of conversations, emails and internet requests

1957 The Soviet Union launches Sputnik, the first artificial satellite to orbit the Earth.

6 I IOP Institute of Physics

1961 Britain launches its first satellite, Ariel 1, to study the ionosphere, the upper atmosphere at the edge of space.

1981 The University of Surrey launches its first satellite with the help of NASA, the American space agency.

2008 Surrey Satellite Technology, a spin-off company from the University of Surrey, is sold to Astrium, a subsidiary of the Franco-German aerospace giant EADS, for a reported £50 m.

Over the past decade, the space industry directly employed 30,000 people and reported a turnover of £9.1 bn in the year 2010/11.

can be handled simultaneously. Three-fifths of people living in the UK now own a smartphone, and half of drivers use satellite-navigation, further increasing the traffic that satellites handle. Earth observation Satellites can be used to gather information about the planet. This can be used to develop scientists’ understanding of climate change, which is widely expected to cost the world economy up to three per cent of its global output by 2050. It is also used to provide weather forecasts, which enable energy companies to stock up on fuel prior to a cold snap and farmers to plan their work. Satellites can monitor natural disasters, such as floods, hurricanes, earthquakes and tsunamis, and enable people to devise how best to respond. Military British satellites provide secure and reliable communications that can provide high data rates to small and remote units typically used in an initial response to disasters and rescue operations, as well as for military operations. Four military communications satellites with anti-jamming antenna orbit the Earth and can be steered to focus onto particular regions of the world as needed. The satellites were designed and built by UK Astrium, which operates the constellation on behalf of the UK Ministry of Defence. Manufacturing and operating systems Just over 10% of the revenues from the space industry come from building spacecraft and the operating systems needed to control them from the ground. Most satellites are used for broadcasting and communications but British scientists also build satellites for scientific purposes and for foreign customers, including Algeria, China, Chile, Germany, Malaysia, South Korea, Thailand and the United States. Astrium UK recently won a £260 m contract to build a spacecraft that will orbit the Sun for the European Space Agency; a second British 2009 Despite the economic recession, Britain’s space industry maintains an average annual growth rate of 7.5%.

2010 The coalition government launches the UK Space Agency.

2030 Britain aims to have 10% of the international market share of space, up from six per cent in 2009.

June 2013 Physics: transforming lives


The space industry

company that it recently acquired, Surrey Satellite Technology, has a contract worth about £190 m to build satellite-navigation systems for the European Union’s network of satellites, which will provide an independent alternative to the US Global Positioning System and Russia’s GLONASS. In 2011 DMC Imaging International, a subsidiary of Surrey Satellite Technology, won a £110 m contract to supply a Beijing company with images from its satellites, which accounted for about 10% of the UK’s high-technology exports to China that year. Future Britain’s international market share in space was estimated to be six per cent in 2009 but the UK Space Agency, launched in 2010, aims to boost it to 10% by 2030, which would generate a turnover of £40 bn. The UK has more than a hundred small space firms each with turnovers of less than £1 m, some of which are expected to grow significantly or to be bought by bigger organisations. The Organisation for Economic Co-operation and Development (OECD) suggests that satellites will power the growth in availability of broadband in rural areas, the delivery of high-definition and 3D television and improved air-traffic management within 8 I IOP Institute of Physics

the next five years. Automatic identification systems via satellite will allow countries to monitor shipping along their coastlines, enabling the closer monitoring of potential environmental and security problems. Facts and figures


jobs are generated elsewhere for every job created in the space industry

£8.2 bn value-added contribution to UK GDP in

2010/11 through the multiplier impact

+ potential £40 bn turnover boost to the sector by 2030

+ 100,000 new jobs by 2030 + tonnes of carbon40 m dioxide emissions a year could be saved by satellite internet

Liquid-crystal displays

Physics research is revolutionising consumer electronics.

The science Liquid crystals flow like a fluid but have molecules that can be oriented in a crystal-like way. A thin film of the material can be sandwiched between two glass slides that are coated with transparent electrodes and connected to an electrical power source, as the optical properties of the film can be controlled by a voltage. When the power is switched on, the molecules line up in one direction; when it is switched off, they flip to another arrangement. A liquid-crystal display (LCD) is typically made using thousands of electrodes, each of which is controlled individually. Detailed and rapidly moving images can be created by switching the individual elements on and off. A truly international venture LCDs were first developed in the US but British scientists invented the first stable liquid crystals and the technologies needed to use LCDs for televisions, and licensed their expertise worldwide. In recent years, South Korea has become dominant at manufacturing the devices. What physics does it rely on? −− Condensed-matter physics −− Optical physics −− Materials physics −− Physical chemistry −− Mathematics Impact LCDs were first developed for pocket calculators and digital wristwatches in the 1970s but the global market for flat-panel displays is now worth about £100 bn, of which LCDs form the largest segment. Despite the economic downturn, sales are expected to grow modestly in 2013. Over the years, the technology has generated substantial revenues for the UK, mostly through royalty income from patents.

June 2013 Physics: transforming lives


Liquid-crystal displays

Applications LCDs can be made almost any size, from small screens just centimetres across to large ones several metres across. They are used in devices such as televisions, computer monitors, smartphones, handheld video games, cameras and satellite-navigation systems. Televisions Almost all televisions now use LCDs to produce images. The sets are thinner and lighter than the previous technology, enabling people to fit bigger screens into their homes. Most televisions bought in the UK are made abroad, but Cello Electronics, which is based in Bishop Auckland in the north-east of England, manufactures devices for sale under retailers’ own brands both at home and elsewhere. It has invested heavily in research and development to bring new technology to the UK market at the same time or earlier than many of its Japanese and South Korean competitors. The company recently opened a new factory where it is expanding production for sales in Europe, particularly Germany. Staff working at Sharp Laboratories Europe, based in Oxford, also develop LCDs for new applications. These include a screen that can display different content to viewers, enabling a couple equipped with two sets of headphones to enjoy two different television programmes on the same screen simultaneously. Smartphone screens All of Apple’s iPhones and many other smartphones use LCDs. In 2013, Russian company Yota Devices demonstrated a dual-screen phone with an LCD that allows people to watch high-definition television or to flick through detailed photographs on their smartphones and an electronic paper display that enables them to show electronic tickets and boarding passes – even after they have exhausted the device’s battery.

1889 Physicist Otto Lehmann uses a polarising microscope to study liquid crystals and recognises that they represent a new state of matter.

10 I IOP Institute of Physics

1936 The first patent to claim a potential display application of liquid crystals is granted to the UK Marconi Wireless Telegraph.

1972 George Gray and Ken Harrison of the University of Hull and Peter Raynes of the Royal Signals and Radar Establishment in Malvern invent the first liquid crystals suitable for mass production.

1978 Cyril Hilsum of the Royal Signals and Radar Establishment and colleagues at the University of Dundee invent the technology needed for the liquidcrystal picture-element switches now used in all televisions.

Over the years, LCD technology has generated substantial revenues for the UK, mostly through royalty income from patents.

Games consoles Handheld video games systems, such as the PlayStation Portable and the various devices produced by Nintendo, use LCDs in their screens. In 2011 Nintendo launched its glasses-free, 3D games console, the Nintendo 3DS, and sold 113,000 of the devices in the UK in just two days. Electronic paper LCDs can be used to make electronic paper, which looks like ordinary paper but which can be altered centrally to enable consistent information to be displayed across a wide area. ZBD Solutions, based in Ascot, supplies electronic paper to customers throughout Europe and has recently signed a deal with the John Lewis department store in Exeter to provide it with displays that customers can use to see the prices of products on the shelves and to discover more information about them. The company emerged in 2000 from the same British laboratories where the first liquid crystals suitable for mass production were developed. Future The first commercially available televisions to use LCDs to produce 3D images to viewers wearing special glasses went on sale in the UK in 2010. Since then, companies have developed devices that produce 3D effects without the need to wear special eyewear. High-definition televisions that use LCDs are also expected to be popular with viewers. The BBC has already begun to film its first wildlife documentaries to make use of the technology.

1985 Seiko Epson unveils the first commercial colour television to use an LCD.

2007 Worldwide sales of LCD televisions outstrip cathode-ray tubes for the first time.

2013 At the annual Consumer Electronics Show in Las Vegas, where electronics manufacturers show off new technologies, a smartphone with an LCD wins a best-inshow award.

June 2013 Physics: transforming lives

I 11

Liquid-crystal displays

Key facts and figures

+ of televisions use 90% LCDs and screens are 10% bigger than three years ago


the resolution of current high-definition television screens — these will go on sale in 2013

+ LCD televisions 260 m are predicted to be sold worldwide in 2015

12 mths

to recoup the cost of switching to electronic paper displays in shops

+ in UK £100 m royalties from licensing its liquidcrystal inventions

Zero smartphones and other mobile technology would not have been possible without LCDs

12 I IOP Institute of Physics

Sharp Laboratories Europe develop LCD applications including a screen that can display different content to viewers, enabling a couple to enjoy two different television programmes on the same screen simultaneously.

Plastic electronics

A new technology promises light-weight and flexible electronic devices.

The science Semiconductors are the foundation of modern electronics. Traditional electronics are reliant on inorganic semiconductors, for example, silicon and gallium nitride alloys with varying fractions of indium. By contrast, modern organic electronics, used widely in smartphone displays, work with carbonbased semiconducting (i.e. conjugated) polymers and small molecules. Carbon-containing “organic” molecules that sublime on heating can be laid down using thermal vacuum deposition techniques similar to those used to create thin films of metal on many surfaces. Alternatively, solution-based processes including printing techniques analogous to those employed in the traditional printing industry can be used for those molecules that dissolve in suitable solvents. Long-chain molecules, or plastics, generally fall into the latter category. Illuminating work The UK is at the forefront of discoveries in plastic electronics: in 1989 physicists at the University of Cambridge discovered that certain plastics could be made to generate light when wired up to an electrical power source. The nation has created a network of five centres of excellence in plastic electronics to exploit this lead. More than 20 universities and dozens of small companies and multinationals now develop the technologies in the UK. What physics does it rely on? −− Molecular physics −− Materials processing −− Semiconductor physics −− Optics −− Printing and graphics science Plastic can also be made to emit light by sandwiching it between two electrodes, one of which injects electrons and the other “holes”. When these meet, light is generated.

June 2013 Physics: transforming lives

I 13

Plastic electronics

Impact Carbon-based electronics was worth an estimated $10 bn worldwide in 2012, most of which was in display technologies. IDTechEx, a market analyst, suggests that by 2022 the total market will be worth more than $60 bn, rising to $350 bn by 2032. In 10 years’ time, it predicts that about a third of carbon-based electronics will be produced on flexible surfaces. More than 3000 organisations are pursuing various versions of the technology, including printing, electronics, materials and packaging companies. Applications Plastic is widely used because it is cheap and easy to make and handle. Plastic electronics can create new sources of light for homes and offices, generate electricity from the most abundant source of power on the planet – sunlight – and be used to make cheap, disposable medical devices. The most popular electronic display screens currently use vacuum deposited carbon-based molecules, but flexible printed displays could soon become the dominant technology. Lighting Light sources made from carbon-based electronics offer an alternative, environmentally friendly way to produce light. They can be used to construct walls or screens that light up. The panels can also be transparent, allowing windows to transmit natural light by day and to generate a soft glow by night. As a demonstration of the technology, General Electric has incorporated printed electronics into a set of protective clothing for fire fighters that shines brightly in the dark. The devices could even form part of soft furnishings such as curtains. Several European companies, including OSRAM and Philips, already sell desk lamps that use small-molecule electronics to generate light and Thorn Lighting in the UK is working with Cambridge Display Technology to develop lamps that use printed

1970s Physicists and chemists discover that, instead of acting as insulators, some plastics can be made to conduct electricity.

14 I IOP Institute of Physics

1989 The physicists Donal Bradley, Jeremy Burroughes and Sir Richard Friend at the University of Cambridge succeed in manipulating thin sheets of plastic to generate light.

1992 The same physicists join with colleagues to form Cambridge Display Technology, which is sold in 2007 for a reported $285 m.

2002 Printed electronics feature in a James Bond film, Die Another Day; the Philips shaver incorporates them in its display.

Carbon-based electronics was worth an estimated $10 bn worldwide in 2012, rising to $350 bn by 2032.

electronics. Almost every lighting company is engaged in research and development of the technologies. Solar power Carbon-based solar panels offer certain advantages over traditional devices. They are light-weight and rugged; they can be made to cover large areas; they generate electricity even on gloomy days; and they could be made cheaply. Five start-up companies have emerged in the UK over the past five years to work on solar-energy generation including the development of solar-powered lamps for use in poor communities abroad that have no access to the electricity grid. Many European companies are developing plastic electronics to build solar cells that would be flexible and light-weight, and so fit onto roofs easily. The solar cells can also be made visually transparent so that they could be fitted over skylights. In principle, solar cells could be printed directly onto windows, embedding the generation of electricity from solar power in new homes. Some manufacturers have begun to attach flexible plastic solar panels to the outside of laptop bags, enabling the bag to recharge smaller electrical items such as smartphones. Medical devices Plastic electronics are being used to develop portable, point-of-care medical devices capable of achieving similar results to much more expensive laboratory-based instruments. Molecular Vision, a spinout company from Imperial College London that is now part of the Abingdon Health Group, has developed a lab-on-a-chip device that combines a light source with a detector. It can test a single sample of blood or urine to identify kidney disease or whether someone has recently had a heart attack. The same technology could be used for

2009 The Department for Business, Innovation and Skills launches the UK Strategy for Plastic Electronics.

2012 Some 45 companies and more than 20 universities in the UK are engaged in the research and development of plastic electronics.

2013 The most successful products yet to use carbonbased electronics – the Samsung Galaxy smartphones – sell more than 100 million devices.

June 2013 Physics: transforming lives

I 15

Plastic electronics

veterinary testing, forensic science and detecting environmental pollution. Screens and displays Carbon-based light-emitting devices are found in sleek, lightweight products such as some of the latest smartphones, and are a complementary technology to LCDs. Samsung, for example, uses them to display images on the screens of its best-selling devices, and LG Displays, another South Korean company, is due to begin mass production of competitively priced televisions that will use them in 2013. The televisions will produce clearer and faster-moving images than many current devices and will be lighter, thinner and more energy-efficient than a number of the flat-screen televisions commonplace today. Cambridge Display Technology and Seiko Epson produced an ink jet printed TV display prototype in 2003/04. Additionally, Sony recently unveiled its first television display to use printed electronics. Many companies now seek to switch from printing onto glass to flexible substrates that would bend easily and, unlike their glass-substrate counterparts, would not shatter when dropped.

16 I IOP Institute of Physics

Future Plastic electronics might be used to make smart packaging for pharmaceuticals. Blister packs of drugs could sound an alarm to alert patients who had failed to dispense their medicine on schedule. The technology might also be used to monitor the condition of food inside its packaging so that consumers did not have to rely on the bestbefore date. Fashion designers could join those who have already experimented with fabrics that emit coloured light and artists who have created illuminated designs. Plastic electronics could become ubiquitous, creating a wealth of intelligent but cheap products that would change business models and create new sources of revenue.

Plastic electronics

The first television display to use printed electronics was recently unveiled. Many companies now seek to switch from printing onto glass to flexible substrates that bend easily and do not shatter.

June 2013 Physics: transforming lives

I 17

Plastic electronics

Facts and figures

£70 m

has been invested by the government in university projects of direct relevance to plastic electronics

$60 bn the predicted global worth of plastic electronics by 2022

$350 bn the estimated worth of the global carbon business by 2032


of household carbondioxide emissions due to lighting might be cut by 2050 if carbonbased electronics were used

18 I IOP Institute of Physics

Plastic electronics might be used to make smart packaging for pharmaceuticals. Blister packs of drugs could sound an alarm to alert patients who had failed to dispense their medicine on schedule. The technology might also be used to monitor the condition of food inside its packaging so that consumers did not have to rely on the best-before date.

Radio-frequency identification tags New uses of a Second World War technology could revolutionise life in the internet age.

The science A radio-frequency identity (RFID) system consists of a small electronic chip embedded in a plastic tag or card, and a radio-frequency transmitter and receiver, which reads the chip, depending on the type of tag, when it is anything between a centimetre and 100 m away. The reader transmits encoded radio signals to interrogate the tag, which provides the electronic chip with sufficient power to transmit information to the reader using the reflected radio signal. Through the ages Many types of radio-frequency identification tags are the direct descendants of devices that were attached to aircraft during the Second World War. British-developed radar could detect aeroplanes but could not identify friend from foe, so the Allies fitted their planes with tags that broadcast their allegiance when interrogated from the ground. What physics does it rely on? −− Electromagnetism −− Semiconductor physics −− Materials science Because the tag can use the energy transmitted by the reader to power its response, it can work without batteries. Such RFID tags are relatively small, light-weight and cheap to make. Impact The RFID market was worth $7.7 bn worldwide in 2012, according to market analyst IDTechEx. Its figures show that the UK is currently the biggest user of RFID technology in Europe. The technology has enabled train and bus companies to introduce simpler fares and to cut journey times. This makes public transport more appealing, helping to reduce greenhouse gas emissions and paying off in other ways besides: the Cabinet Office estimates that congestion, poor air quality, accidents and physical inactivity all impose costs of around £10 bn every year in urban areas in the UK.

June 2013 Physics: transforming lives

I 19

Radio-frequency identification tags

Applications The use of RFID tags is becoming ever more widespread. In recent years UK companies have introduced them to create electronic tickets for use on public transport, speed up shoppers queuing at tills, enhance security checks at airports and track objects in the supply chain. Public transport Oyster cards containing RFID tags were introduced on the London public transport network in 2003. Today some 55 million cards have been issued and more than 80% of journeys made on public transport in London involve using an Oyster card. The technology enables computers installed in the gates of the Tube network to calculate the correct fare to charge from 1.83 million possible journey permutations in 200 milliseconds, speeding passenger flow through each station. A third of the growth in public-transport use in London over the past few years is due to fares reform that has been boosted by RFID chips, according to a study by Peter White of the University of Westminster. He suggests that the use of the technology to speed the boarding of buses saves passengers as much time as the creation of bus lanes. Bank cards Retailers who want to accept contactless payments to cut queues are installing devices to read the RFID tags that are being placed in bank cards. Some five million contactless payment cards have been issued by banks in the UK and the form of payment is now accepted by 100,000 retailers. Shoppers can simply tap their bank cards against an electronic reader to pay for cheaper items such as lunch-hour sandwiches.

1873 James Clerk Maxwell, a Scottish theoretical physicist, elaborates equations that unify the theories of electricity and magnetism.

20 I IOP Institute of Physics

1897 Morse code signals transmitted across Salisbury Plain in England using radio waves.

1935 British physicist Sir Robert Alexander Watson-Watt develops radar that can be used to detect passing aeroplanes.

1940s Radio transmitters that identify an aeroplane as friend or foe when interrogated by radar are placed on aircraft during the Second World War.

The RFID market was worth $7.7 bn worldwide in 2012. The UK is currently the biggest user of RFID technology in Europe.

Passports The technology is also being used for national security. The UK is one of almost 100 countries that are introducing RFID tags in passports. The chips will help border guards identify whether the person seeking entry is the legitimate holder of the passport and could also be used to automate the process, thereby cutting the queues at immigration. The Identity and Passport Service currently issues more than five million RFID-enabled passports every year and more than half of those people who hold a passport now have the technology embedded in their documents. Logistics The chips are used in logistics because they can be embedded in products and tracked as they leave one factory and enter another. The European Aerospace, Defence and Space Company, EADS, (which owns aerospace companies Airbus, and Astrium, which build civilian and military spacecraft), uses RFID tags to track components through its manufacturing processes. For example, it uses RFID tags to monitor construction of the Airbus A380, a double-decked aeroplane. Over the past few years miniaturisation and mass production have made RFID small and cheap enough to become more widespread. They are now found within some supermarkets, where they are used to monitor stock.

1973 First patent for a radio-frequency identification device intended for use in collecting tolls is filed in America.

2003 Smart cards that use radio-frequency identification chips are introduced to the world’s largest public-transport system in London.

2012 Some 80% of all public-transport journeys in London are made using Oyster cards and the scheme is credited with promoting the Tube and bus network.

June 2013 Physics: transforming lives

I 21

Radio-frequency identification tags

Future Some hospitals are piloting the use of RFID technology to enable staff to know the precise location of a doctor who is on call and to link electronic records to each patient. Others are developing it to help monitor the health of people who are elderly and housebound. The “internet of things” envisages a hugely interactive world in which machines communicate with one another via the internet. Sensors attached to a carton of milk could detect when it was almost empty and instruct the fridge to order more supplies to be delivered from the supermarket, for example. RFID tags would be fundamental to such a world. McKinsey, a consultancy, argues that such technologies would create information networks that produce new business models, improve business processes and reduce costs and risks.

22 I IOP Institute of Physics

Facts and figures

$26 bn the projected value of the RFID market by 2022 55

million Oyster cards have been issued by Transport for London since 2003


rise in the number of bus journeys made in London since 2003

4 bn

RFID tags were sold in 2012. More than 30 million British passports use the technology

Optical fibres

Light-carrying glass fibres have transformed communications and medicine.

The science Optical fibres are fine threads of glass, comprising a core and cladding that are approximately the same width as human hair, which can transmit light over long distances. They can be used to transmit information as pulses of light that travel down the fibres, with little loss of signal compared with copper wires. Cables containing hundreds of optical fibres are robust enough to be laid on the ocean floor, connecting continents as never before and revolutionising telecommunications networks. How do optical fibres work? Optical fibres comprise a thin glass core through which the light travels, coated in a second glass layer that reflects the light back and guides it down the core. Because the optical fibres are flexible, the light they transmit does not have to travel in straight lines and can be sent along a curved path. When used in telecommunications, the individual fibres in a cable can carry many channels, each using a different wavelength of light. Typically each channel transmits information at a rate of 10 or 40 gigabits per second, but rates of 270 gigabits per second have been achieved – equivalent to 350 high-definition movies sent in one second. As well as many channels per fibre, each cable can contain up to 1000 fibres.

1887 Sir Charles Vernon Boys uses quartz fibres for mechanical measurements.

1928 John Logie Baird, inventor of the television, files the first patent demonstrating the fibre-optic principle.

1952 Harold Hopkins and Narinder Kapany of Imperial College London create first endoscope.

1961 Elias Snitzer and Will Hicks at American Optics fire a laser beam through a fine glass fibre.

June 2013 Physics: transforming lives

I 23

Optical fibres

What physics does it rely on? −− Optics −− Optoelectronics −− Lasers −− Photonics Impact The impact of optical fibres is hard to overstate. They have revolutionised telecommunications, transmitting more information over greater distances than could ever be achieved with copper wires, enabling the spread of broadband networks and the many services that depend on them. The world market for fibre-optic components alone is expected to reach $31 bn by 2015. In 2011, 217 million kilometres of optical fibre were produced globally – most of it for optical communications cables – and the market is doubling each year. Physicists in the UK were key contributors in the development of optical-fibre technology. The UK remains a world leader in innovative fibre-optics research and also maintains a strong manufacturing base, with plants in Wales and Southampton. Without optical-fibre cables enabling broadband communications, the internet as we know it today would not be possible. Download services such as iTunes and movies-on-demand require the large data-carrying capacity that optical fibres provide. Around 70 per cent of UK homes now have a fixed broadband connection, which is now a vital part of everyday life underpinning the UK digital economy. Optical fibres have also transformed medicine by enabling laparoscopic procedures to minimise both the pain and healing time compared with conventional surgery, and leave much smaller scars. Patients are often discharged the same day, compared with up to a week in hospital for those undergoing traditional surgery, saving time and money for

1966 Sir Charles Kao and George Hockham of STC Laboratories in Harlow propose the transfer of information over glass fibres.

24 I IOP Institute of Physics

1966 The British Post Office Research Laboratories begin fibre-optic communications research.

1970 US researchers demonstrate glass fibres can transmit 65,000 times more information than copper wires.

1977 Television signals are transmitted using optical fibres.

Physicists in the UK were key contributors in the development of optical-fibre technology. Without optical-fibre cables enabling broadband communications, the internet as we know it today would not be possible.

the NHS. There are dozens of laparoscopic procedures; one of the most common is the gall-bladder operation, over 60,000 of which are currently performed in the UK each year. Applications Telecommunications Optical fibres cover the globe, connecting continents through submarine cables. These are the backbone of the internet and all telecommunications networks. Optical fibres are able to carry many thousands of times more information than copper wires. They provide the large bandwidth required for today’s internet, including downloading music and high-definition videos, via services such as iTunes and Netflix. Optical fibres are ideally suited to undersea cables because they can transmit information with little loss of signal compared with copper wires. This allows distances of 50–100 km between the expensive “repeaters” needed to boost the signal. The invention of the erbiumdoped fibre amplifier in 1987 by physicists at the University of Southampton (and later developed by AT&T Bell Laboratories) allowed the signal to be boosted within the fibre itself, so modern installations do not require repeaters at all. Since they carry only light, optical fibres are immune to electrical interference, so they can also be used for short-range communications, for example in aircraft.

1977 The British Post Office begins sending live telephone traffic through optical fibres.

1977 US telephone companies begin sending telephone calls through optical fibres.

1978 AT&T and the Post Office announce 10 year plan to develop transatlantic optical-fibre cable.

1984 British Telecom (formerly the Post Office) lays the first submarine fibre to the Isle of Wight.

June 2013 Physics: transforming lives

I 25

Optical fibres

Medicine One of the first uses of optical fibres was in the endoscope, which allows doctors to see inside patients’ bodies without expensive and invasive surgery. This paved the way for “keyhole” surgery, in which optical fibres not only relay images but can also be used to send a laser beam to carry out surgery, so only a tiny opening is needed. Fibre lasers Fibre lasers, also developed at Southampton, can have active regions of several metres wound into efficient, compact designs that can generate very high-power beams. They are used in laser cutting and welding, and they are a candidate for the next generation of research lasers emitting extremely intense X-ray light. Sensors Optical fibres make excellent and inexpensive sensors for environmental, chemical and biological monitoring in such places as mines, oil wells and other remote locations. When the fibre is stretched or heated, this alters the characteristics of light transmission along it. The fibre-optic research group at the University of Southampton is working with a local company, SENSA, to develop a temperature sensor that can work across a distance of 100 km. They are also developing a strain sensor for monitoring large structures like bridges, dams and roads.

1986 The first opticalfibre cable across the English Channel begins service.

26 I IOP Institute of Physics

1988 The first transatlantic optical-fibre cable begins service.

1987 Physicists at the University of Southampton announce “optical” amplifiers that are built into optical fibres, removing the need for repeaters.

1991 Japanese researchers successfully send a signal through 1 million km of fibre.

Optical fibres cover the globe, connecting continents through submarine cables. These are the backbone of the internet and all telecommunications networks.

Future Work continues to increase the capacity of optical-fibre cables and reduce the cost of installing them. In the last decade the use of “optical amplifiers” – sections of fibre “doped” with elements to boost the signal – have done away with the need for expensive repeaters. Other developments include the use of “optical solitons” that have enabled the development of ultra-fast communications across vast distances. One of the most exciting developments are photonic crystal fibres, developed by Philip Russell and colleagues at Southampton and Bath universities. These have air channels surrounding the central core, which allows light to be manipulated in many novel ways that could lead to the development of high-power lasers and gas sensing. The most significant application is the laser generation of white light (“supercontinuum” generation), which can be tuned to particular wavelengths for advanced microscopy in the biosciences. UK researchers are also making optical fibres out of materials other than glass. For example, plastic optical fibres could be used for transmitting information around the house or be incorporated into textiles and clothing as sensors.

1996 Philip Russell at the University of Southampton demonstrates the photonic crystal fibre.

1997 The 28,000 km “fibre-optic link around the globe” connects the UK and Japan through one continuous cable.

2003 Optical fibres connect all of the continents except for Antarctica.

2009 Sir Charles Kao is awarded the Nobel Prize in Physics for his work developing optical fibres.

June 2013 Physics: transforming lives

I 27

Optical fibres

Facts and figures

£31 bn expected value of world market for fibre-optic components by 2015

28,000 km

the length of one continuous opticalfibre cable around the globe, linking the UK and Japan

1.1 m

kilometres of undersea optical-fibre cable had been installed worldwide in 2010

1.35 bn kilometres of optical fibre currently in service across the world

60,000 gb capacity of the planned submarine cable to connect Ireland to New York in 2013

60,000 laparoscopic gall bladder operations in the UK each year


of bowel cancer operations are now performed via keyhole surgery

28 I IOP Institute of Physics

UK researchers are now making optical fibres out of materials other than glass. For example, plastic optical fibres could be used for transmitting information around the house or be incorporated into textiles and clothing as sensors.

Cancer treatment

Research into the nature of matter and the structure of the universe has led to life-saving techniques to diagnose and treat cancer.

The science Cancer refers to a wide group of diseases in which cells divide uncontrollably, producing a tumour that seriously disrupts surrounding tissues. When cancers are particularly aggressive, these outof-control cells can also spread to other parts of the body, causing yet more damage. Radiotherapy involves directing high-energy radiation – such as X-rays and beams of particles, including electrons and protons – at a tumour to destroy it. The aim is to damage the DNA of the cancer cells to stop them proliferating, while ensuring that the radiation dose received by healthy tissue is small enough that it can recover. The particle accelerators that produce these high-energy beams were originally developed for the study of particle and nuclear physics. The chances of surviving cancer are greatly enhanced by early and accurate diagnosis, and knowing its precise location and size. Here, too, physics has provided many of the most important tools. Exploring the structure of the universe on the very small scale (atomic, nuclear and particle physics) or the large scale (astronomy and cosmology) requires the development of new ways of “looking” at things that cannot be seen with the naked eye. This ability to visualise what cannot ordinarily be seen has led to the advanced imaging that underpins modern medical diagnostics. How does radiotherapy work? When a charged particle or an X-ray passes through any substance, it knocks out electrons, leaving a trail of ionisation. When it passes through the body, this ionisation can cause a break in one or both of the spirals that make up the DNA inside cells. If the damage is small, the cell’s natural repair mechanisms can fix it. But a complex double-strand break – in which there are multiple breaks close together in each helix – is too difficult to repair, leaving the cell unable to reproduce successfully. By carefully designing the treatment plan to accumulate a high radiation dose in the tumour, while keeping the dose to normal tissue low enough for repair mechanisms to work, the tumour can be destroyed.

June 2013 Physics: transforming lives

I 29

Cancer treatment

What physics does this rely on? −− Medical physics −− Electromagnetism −− Particle physics −− Nuclear physics −− Astrophysics −− Atomic and molecular physics −− Acoustics −− Materials science −− Computational physics Impact One in three people will get cancer at some point in their lives. The chance of getting cancer increases with age, with about two-thirds of cancers occurring in people over the age of 65. In 2010, there were around 157,250 deaths from cancer in the UK. Although cancer survival rates have doubled in the past 40 years, the number of sufferers increases each year because of advances in diagnosis and an ageing population. More than half of cancer patients will receive radiotherapy as part of their treatment, and radiotherapy contributes about 40% to the successful treatment of cancer. Half of the world’s 20,000 particle accelerators are in use in hospitals, and each can treat between 4500 and 6500 patients per year. Increasingly, patients are being treated with more advanced radiotherapy treatments, such as proton-beam and gamma-ray therapies. In 2012 approximately 70,000 patients worldwide received proton beam therapy, but it is estimated that 137,000 patients per year could benefit from the treatment in the US alone. Worldwide there are around 150 Gamma Knife units, which have collectively treated around 500,000 patients with brain tumours.

1895 German physicist 1896 French physicist Wilhelm Röentgen Henri Becquerel discovers X-rays. discovers radioactivity from uranium and Marie Curie theorises that its source is the atom itself, for which they receive the Nobel Prize in Physics in 1903.

30 I IOP Institute of Physics

1903 Discovery of the Bragg Peak by Sir William Bragg – the basis of proton and ion-beam therapy.

1911 Discovery of superconductivity by Heike Onnes. Superconductivity enables the strong magnetic fields used in MRI.

Early detection of cancer through physics-based imaging techniques greatly increases the chances of successful treatment. Better diagnosis and shorter waiting times also means an enhanced quality of life.

The Department of Health announced a £250 m investment to build two proton-beam therapy centres in the UK by 2017. It is estimated that more than 1500 patients per year would benefit from the establishment of a new National Proton Beam Therapy Service in the UK. Today there are 43 proton and carbon-ion centres worldwide, and 23 more are planned or under construction. The UK is a key supplier of component parts for these modern accelerators. Early detection of cancer, for example through physics-based imaging techniques, greatly increases the chances of successful treatment. Better diagnosis and shorter waiting times also mean that people living with the disease can have an enhanced quality of life. In addition to the human costs of the disease, cancer also exacts huge economic costs. The direct healthcare expenditure in the UK is £5.6 bn a year. There are also additional costs through time off work, the impact on family and friends of continuing care, and the loss of productivity due to premature death. Applications Cancer diagnostics There are several sophisticated diagnostic techniques that are based on physics, and the number is growing. Computed tomography Computed tomography (CT) scanners use X-rays to produce 3D images of the internal anatomy, using sophisticated software to reconstruct the image. They were first developed by physicists in the 1960s, and the first scanner was built at EMI Laboratories in Hillingdon, earning its creator Sir Godfrey Hounsfield a share of the 1979 Nobel Prize in Medicine.

1913 Lord Ernest Rutherford – while based at the University of Manchester – and Niels Bohr develop a theory of the structure of the atom.

1914 Research begins at the Sorbonne’s new Radium Institute into medical treatment of cancer using radium.

1928 British physicist Paul Dirac postulates the existence of the positron, for which he was awarded the Nobel Prize in Physics in 1933. These particles are now routinely used for cancer detection in PET.

1929 Cyclotron developed by Ernest Lawrence at Berkley, for which he won the Nobel Prize in Physics in 1939.

June 2013 Physics: transforming lives

I 31

Cancer treatment

Single photon emission computed tomography A single photon emission computed tomography (SPECT) scan is a non-invasive nuclear imaging test that shows the blood flow to tissues and organs and is widely applied in oncology. It uses radioactive tracers that are injected into the blood to produce pictures of blood flow to major organs, primarily in the brain and heart. The tracers generate gamma-rays, which are detected by a gamma camera. A computer then prepares 3D images of the scanned organ. A key feature of this test is that the tracer remains in the blood stream rather than being absorbed by the surrounding tissues, thus limiting the images to areas where the blood flows. Positron emission tomography Positron emission tomography (PET) uses positrons to produce functional images of the body. Positrons are the antimatter version of the electron and their existence was first predicted by British physicist Paul Dirac in 1928. In PET scanning, a positron-emitting radionuclide isotope is attached to a sugar molecule that is absorbed by cells in the body where there is a lot of metabolic activity, such as in growing tumours. Once inside the tumour, the radionuclide emits a positron, which soon meets an electron and the two particles annihilate, emitting a pair of high-energy gamma-ray photons. These pass through the body and are picked up by sensitive detectors. With the use of sophisticated software to analyse where the gamma rays originated, it is possible to create a highly detailed 3D image of the tumour. PET scans are often combined with CT scans to give even more precise information about the shape, size and location of the tumour, as well as the position of nearby critical organs. The accelerators that are used to create the positron-emitting radionuclides, and the gamma-ray detectors that create the PET

1932 Discovery of the positron by Carl Anderson, for which he won the Nobel Prize in Physics in 1936.

32 I IOP Institute of Physics

1944 Isador Rabi receives the Nobel Prize in Physics for his discovery of nuclear magnetic resonance (NMR). This alignment of atomic nuclei in a strong magnetic field is the basis for MRI.

1946 US physicist Robert Wilson proposes the use of protons for cancer radiotherapy.

1952 Felix Bloch and Edward Purcell awarded the Nobel Prize in Physics for showing that nuclear magnetic precision measurements may be made in liquids, leading to the idea of using NMR in living tissue (as in MRI).

Cancer treatment

images, were first produced by particle physicists trying to understand the nature of matter. Magnetic resonance imaging Magnetic resonance imaging (MRI) uses very high magnetic fields and rapidly varying electromagnetic fields to detect the distribution of protons in the body and so create 3D images of the organs. By manipulating the electric and magnetic fields, information about how the body is working can also be obtained. This technology was originally developed to study structure of the atomic nucleus, and makes use of large superconducting magnets. Unlike X-rays, which cannot distinguish the detailed structure of soft tissues, MRI can produce high-resolution images that reveal damaged and abnormal tissue. The related technique of magnetic resonance spectroscopy can be used to map the chemical composition of tumours, and so characterise them without the need for an invasive biopsy. It is capable of predicting the response to chemotherapeutic drugs at an early stage in the treatment cycle, so that if a drug is not effective an alternative can be tried as soon as possible. In the developing field of interventional MRI, tumour surgery can be performed while the patient is inside the scanner, so surgeons can ensure that the whole tumour is removed and avoid the need for repeated operations. Ultrasound In ultrasound scans, high-frequency sound waves are used to create an image of part of the inside of the body. Pulses of ultrasound are sent from a probe through the skin and then bounce back from structures inside the body to be detected by the probe and displayed. Optical coherence tomography Optical coherence tomography (OCT) is a form of “optical ultrasound”.

1951 First cobalt-60 teletherapy unit produced in Canada.

1954 First treatment of cancer patients with subatomic particle beams at Berkeley Radiation Laboratory in California.

1969 Sir Godfrey Hounsfield creates the CT scanner at EMI Laboratories in Hillingdon, for which he shares the 1979 Nobel Prize in Medicine.

1971 First medical CT scan is made, of a cerebral cyst in a patient in London.

June 2013 Physics: transforming lives

I 33

Cancer treatment

Infra-red laser light is shone on the skin and the light that is reflected back from the tissue layers just beneath the surface can be collected to form a very high resolution image. These images are much more detailed than those produced by MRI, but OCT can only penetrate a few millimetres. This makes them most useful in detecting cancer of the skin and oesophagus, for example. Selected ion flow tube mass spectrometry Selected ion flow tube mass spectrometry is a technique that was originally developed by astrophysicists at the University of Birmingham who were investigating the chemistry of interstellar clouds. The technique is able to sense tiny amounts of gas, and can be used to detect certain cancers by analysing a sample of a patient’s breath. Cancer treatment Radiation kills cells, particularly cancer cells, by disrupting DNA and preventing the cells from reproducing. Radiation can be delivered in several ways: External beam radiotherapy Particle accelerators originally developed by physicists to study subatomic particles have been used to generate beams of radiation to treat cancer since the 1950s. Electron linear accelerators (linacs) are the most common in use and create beams of X-rays or electrons. The first electron linac was used for radiotherapy in the Hammersmith Hospital in 1953; today, every major cancer hospital has several electron linacs for radiotherapy. Other linacs are able to produce a variety of radioactive agents that are used in the diagnosis and treatment of cancer. Protons were first suggested as an alternative to X-rays by Robert Wilson in 1946, and the first patient was treated with protons in Berkeley, California in 1954. The first hospital-based proton therapy

1974 The first commercial PET machine is built.

34 I IOP Institute of Physics

1980 The first clinically useful MRI image is produced.

1989 First hospitalbased proton therapy is carried out in Clatterbridge, Wirral.

1992 Development of multileaf collimators at the Christie Hospital in Manchester, which help target the radiation beam more precisely.

Cheaper and more compact accelerators and beamdelivery systems will make proton and light-ion therapy accessible to many more patients.

centre was established in Clatterbridge in the Wirral in 1989, where they treat eye cancer. Modern proton beam therapy is the most precise form of radiation treatment available today. It destroys a primary tumour site but leaves surrounding healthy tissue and organs almost completely intact, making it particularly suited to treating childhood cancers. Brachytherapy Brachytherapy uses artificially produced radioactive “seeds” enclosed inside protective capsules, which are delivered to the tumour, where they emit beta or gamma rays, to give a highly localised dose. The capsules can be removed after treatment, or in some cases left in place. Boron neutron capture therapy Boron neutron capture therapy is used to treat cancers of the head and neck. A non-radioactive form of boron is injected into the tumour and then a beam of neutrons is fired at it. Boron is used because it absorbs neutrons much more readily than human tissue, and when it does it forms lithium ions and high-energy alpha particles, which together deliver the radiation dose to the tumour. Computer-aided treatment Increasingly, computer-based methods are being used together with CT and MRI scans to “sculpt” the beam so that its shape matches that of the target tumour. Alongside image-guided robotic surgery and the use of laser scalpels, this is leading to ever more precise cancer treatment. Future Work continues to refine imaging techniques so that radiation can be targeted to match the tumour shape ever more precisely. Cheaper and more compact accelerators and beam-delivery systems will make proton and light-ion therapy accessible to many more patients. New ideas, such as using nano-particles to increase the radiosensitivity of

1995 First patient is treated with Intensity Modulated Radiotherapy, which uses MRI and CT together with computerised calculations of the best dose-intensity pattern for tumour shape.

2003 Sir Peter Mansfield of the University of Nottingham wins the Nobel Prize in Physiology or Medicine, along with Paul Lauterbur of the University of Illinois, for their “discoveries concerning magnetic resonance imaging”.

2004 Scientists begin working on totally non-invasive cancer tests, such as the breath test, SIFT.

2007 A compact device that can generate THz radiation portably is created at the US Department of Energy, making THz imaging in hospitals viable.

June 2013 Physics: transforming lives

I 35

Cancer treatment

cancer cells while leaving healthy cells unaffected, will allow cancer to be treated with lower radiation doses and thus fewer side effects. A new proof-of-principle accelerator known as EMMA (Electron Machine with Many Applications) is being constructed at the Science and Technology Facilities Council’s Daresbury Laboratory in the UK. While research is at its very early stages, the experience gained in building this machine may prove useful for future proton and carbon-ion accelerators that are used in treating cancer. EMMA is driven by an energy-recovery linear accelerator called ALICE. The latter also drives an infrared freeelectron laser, which is being used together with a scanning near-field microscope as a potential diagnostic tool for oesophageal cancer. The synchrotron light emitted from high-energy electron storage rings – originally developed for use in particle physics – is of much higher quality than that available from conventional hospital X-ray machines, and can be used to produce so-called phase contrast X-ray images. This technology could potentially be developed into a tool to provide an earlier diagnosis of breast cancer, for example. Low-energy terahertz radiation may also have an important role to play in cancer detection. Terahertz radiation can penetrate several millimetres of tissue and could be used to detect skin cancer at a very early stage, as well as cancer of the cervix, breast and colon. It is safer and less invasive than X-rays. The first terahertz cameras were developed by astrophysicists to image the distant universe. Londonbased company Teraview has developed a portable probe, which is currently being trialled. The sensitivity of terahertz imaging can also be improved with the use of gold nanoparticles and infrared lasers.

2012 New laser technique shows potential for future use in breast cancer diagnosis, to detect if abnormalities are malignant or benign.

36 I IOP Institute of Physics

2012 New accelerator-driven infrared free-electron laser and scanning near-field microscope shows potential for the diagnosis of oesophageal cancer.

Cancer treatment

June 2013 Physics: transforming lives

I 37

Cancer treatment

Facts and figures


different kinds of cancer affect all parts of the body, and all can be fatal if left untreated

324,579 people diagnosed with cancer in the UK in 2010

157,250 deaths from cancer in the UK in 2010 70,000 received proton-beam therapy ± patients

in 2012 worldwide

¹⁄develop people in the UK will ³ of some form of cancer during their lifetime

+ of cancer patients will ½ receive radiotherapy as part of their treatment


have undergone Gamma Knife treatment for brain tumours


proton and carbon-ion centres available worldwide; 24 more are planned or under construction

10,000 hospital £5.6 bn the annual particle accelerators worldwide, direct cost of all cancers to the UK economy

38 I IOP Institute of Physics

treat 4500–6500 patients per year

Physics and DNA

The discovery of DNA structure heralded the birth of molecular biology – physicists, chemists and biologists work together to unravel the basic processes of life.

The science Deoxyribonucleic acid – DNA – is a large molecule that is found in the cells of all living things, from bacteria to humans. It consists of a very long strand of millions of nucleotide “base pairs” joined together in a characteristic double helix. The discovery of the structure of DNA in 1953 by biologist James Watson and physicist Francis Crick was groundbreaking because it provided an explanation of the basis of heredity, what genes are and how they work. The double helix can be unravelled into its two halves and then copied when cells multiply. During reproduction, DNA strands from each parent are able to join together to form a completely new and unique set of strands. Genes work because the bases form a code in which combinations of three bases translate into any one of 20 amino acids. Depending on the precise sequence of the code, amino acids are joined together in different ways to form proteins that make cells and organisms function. How was the structure of DNA discovered? The technique used by Watson and Crick to work out the structure of DNA was X-ray crystallography, which had been developed by physicists Sir Lawrence Bragg and his father Sir William Bragg earlier in the century. The Braggs found that when crystal structures are illuminated with X-rays, atoms within the crystal scatter the X-ray light to produce characteristic patterns. Using the angle of scattering and its intensity it is possible to work out the 3D structure of the molecules that make up the crystal. The discovery also depended on the work of Maurice Wilkins and Rosalind Franklin at the then newly formed Medical Research Council Biophysics Unit at King’s College London. They used fibres of DNA to produce the X-ray diffraction patterns that Watson and Crick studied. In 1953 they finally made their breakthrough discovery – that DNA is a double helix with a phosphate backbone on the outside and the nucleotide bases on the inside.

June 2013 Physics: transforming lives

I 39

Physics and DNA

Following the discovery of the structure, it was physicist George Gamow who first predicted that a three-letter code was needed to produce the 20 amino acids, which lead to Crick and Watson to enumerate the 20 amino acids common to most proteins. It was Crick’s knowledge as a physicist that enabled him to solve the mystery of DNA’s structure. This was done using X-ray crystallography, which continues to be extremely useful in determining the structure of proteins. Today, new techniques from physics are being used to understand yet more about the structure and function of biological molecules, and this understanding is used to create drugs and other treatments for diseases. What physics does it rely on? −− X-ray diffraction −− Nuclear physics Impact The discovery of the structure of DNA led to the development of the field of molecular biology, in which physicists, chemists and biologists work together to understand the basic processes of life. This understanding has led to many advances in the treatment of disease. DNA sequencing also enabled the development of “DNA fingerprinting”, which has had a huge impact in solving crime. The UK National DNA Database now contains over six million samples and is growing by 30,000 per month. As of December 2012, there have been 428,097 crimes matched against the database. According to the UK Medical Research Council, the industry based on genomics – including gene-based services, diagnosis and potential drugs – is worth £3.5 bn a year. In the US, it has been estimated that spending $2 bn on research in this area over the next decade could generate a return of between four and 30 times that investment. 1915 UK physicists Sir William Bragg and Sir Lawrence Bragg receive Nobel Prize in Physics for X-ray crystallography.

40 I IOP Institute of Physics

1953 UK physicist Francis Crick and US biologist James Watson discover the structure of DNA, with contributions from UK physicists Maurice Wilkins and Rosalind Franklin.

1962 Nobel Prize in Medicine awarded to Crick, Watson and Wilkins

1975 The first complete genome is sequenced – of a bacteriophage.

According to the UK Medical Research Council, the industry based on genomics – including gene-based services, diagnosis and potential drugs – is worth £3.5 bn a year.

Applications DNA sequencing In the 1970s, US theoretical particle physicists Walter Gilbert and Allan Maxam developed a method for reading or “sequencing” the bases of DNA, which involved the use of radioactive markers to label sections of DNA. In 1977 Frederick Sanger simultaneously developed a similar method, which led to the Nobel Prize in Chemistry in 1980. The Sanger method has since been adapted and automated, and it was this technique that was used to sequence the entire human genome, along those of more than 180 other organisms. Knowledge of the DNA sequences of genes is crucial to the development of modern drugs and vaccines. DNA sequencing also led to the development of DNA fingerprinting, which was developed in 1985 by Sir Alec Jeffreys at the University of Leicester. By analysing the patterns of certain sections of DNA that vary from individual to individual it is possible to create a “fingerprint” that is unique to each person. This technique has revolutionised crime detection across the world. Proteomics Just as X-ray crystallography revealed the structure of DNA, the same technique is also invaluable in studying the structure of the proteins that genes encode. New and powerful machines are now available to do this work. For example, the Diamond Light Source in Oxfordshire, which opened in 2007, is a powerful synchrotron that accelerates electrons to nearly the speed of light, and in so doing produces incredibly bright beams of light, including X-rays. These can be used to provide exceptionally detailed information about the structure of proteins. The Diamond Light Source has recently enabled scientists to produce a synthetic vaccine against foot-and-mouth disease. This technique could be used to produce safer and more transportable vaccines for many other diseases in the future. 1980 Frederick Sanger and Walter Gilbert receive the Nobel Prize in Chemistry for DNA sequencing.

1985 Sir Alec Jeffreys at the University of Leicester invents DNA fingerprinting.

1987 Applied 1990 Gene therapy Biosystems markets the first carried out. first automated DNA sequencing machine.

June 2013 Physics: transforming lives

I 41

Physics and DNA

42 I IOP Institute of Physics

By using synthetic DNA, researchers have demonstrated a way of delivering a targeted dose of drugs or genes directly to the inside of cells with the potential to target cancer cells.

Alongside these X-ray studies, physicists also use a technique known as neutron scattering, which uses beams of subatomic particles. Additionally, nuclear magnetic resonance – another technique based on physics research – is also used to study the structure of proteins and other biological elements, and often all of these techniques are combined along with genetic manipulation methods to understand biological processes. Future New, extremely powerful X-ray devices known as “free-electron lasers” are being developed that would not only show the structure of proteins but could also enable snapshots of molecular biological processes to be recorded as they take place. This would allow even more detailed understanding of how the body works, providing yet more strategies for treating disease. New methods of DNA sequencing are being developed all the time, and it is now possible to produce DNA microarrays, which can sequence an entire genome in a single device no bigger than a postage stamp. Some of these methods involve physics — such as the use of “quantum dot” nanocrystals as fluorescent markers, instead of conventional dyes. The inspiration also works in the other direction, from biology to physics, as physicists begin to design nanoscale devices made of DNA that are able to self assemble. These might be used for molecular sensing or intelligent drug delivery, for example. By using synthetic DNA to make nanoparticles known as DNAsomes, researchers have demonstrated a way of delivering a targeted dose of drugs or genes directly to the inside of cells; this method of drug delivery has the potential to target particular kinds of cells, such as cancer cells.

1994 American computer scientist Leonard Adleman proposes the DNA computer.

1994 Affymetrix produces the first DNA microarray, using semiconductor manufacturing techniques.

1997 Dolly the sheep is the first cloned mammal.

2000 Human genome project is completed.

June 2013 Physics: transforming lives

I 43

Physics and DNA

Facts and figures


crimes matched against the UK National DNA Database

1 day the amount of time taken to sequence a human genome

+ organisms have had 180 their genomes sequenced to date

£3.5 bn the value of the global market in genomics,

gene-based services, diagnostics and potential drugs

The inspiration also works in the other direction, from biology to physics, as physicists begin to design nanoscale devices made of DNA that are able to self assemble. These might be used for molecular sensing or intelligent drug delivery, for example.

10 trillion the number of simultaneous

calculations that cubic centimetre-sized DNA computer could theoretically perform

2007 The UK Diamond Light Source starts operation.

44 I IOP Institute of Physics

2012 Early research into using DNA for high-capacity information storage.

2013 Synthetic vaccine for foot-and-mouth disease produced using data obtained from the Diamond Light Source.

Energy efficiency

Physics is providing a multitude of ways toreduce energy use, significantly reducing both costs and carbon-dioxide emissions.

The science Whenever we use energy – to light or heat our homes, or to operate electrical appliances – some of that energy is wasted. No process is 100% efficient but by making use of principles from physics, it is possible to increase energy efficiency considerably, and so reduce the amount of energy that is lost. For example, at least 95% of the electricity consumed by an incandescent light bulb is turned into heat. Light-emitting diode (LED) light bulbs, developed from modern condensed-matter physics, are 10 times more efficient and last much longer. When electricity passes through wires, energy is lost as it encounters resistance. But some special materials, under the right conditions, are able to transmit electricity with no resistance at all. These “superconductors” have the potential to save considerable amounts of energy that is otherwise lost as unwanted heat. How do LEDs work? LEDs are made from electroluminescent crystals, which emit light when an electric current is passed through them. An LED is made of two layers – one that has extra electrons and one that has spare “holes” where electrons can sit. When a current passes through the LED, the extra electrons travel to the holes, releasing a photon – a particle of light of a specific colour, depending on the precise make-up of the material. The first LEDs produced red light, but by adjusting the chemical composition of the electroluminescent crystals it is now possible to produce LEDs of many different colours. White light for LED light bulbs may be obtained from a combination of red, green and blue LEDs. Another more commonly used technique involves coating a blue LED with phosphors, which convert the light into a broad spectrum of white light suitable for both commercial and domestic lighting.

June 2013 Physics: transforming lives

I 45

Energy efficiency

What physics does it rely on? −− Opto-electronics −− Semiconductors −− Condensed-matter physics −− Low temperature physics −− Materials science −− Thin films −− Plasma physics Impact Energy efficiency plays a huge role in both reducing carbon-dioxide emissions and saving money for householders and businesses. Today, 20% of the world’s electricity is used for lighting, and this could be reduced to four per cent with optimal use of LED lighting. In the UK this would result in 40 million tonnes less carbon dioxide being emitted each year – a reduction of around eight per cent of total emissions. In the US, the switchover would result in financial savings of $30 bn a year. Worldwide, the switchover to LEDs would enable the closure of 560 major power plants and result in annual carbon-dioxide savings equal to that emitted by all of the cars on the planet. Other technologies have similarly impressive impacts. In Europe, carbon-dioxide emissions could be reduced by 85 million tonnes per year – 25% of the EU’s current reduction target – through the optimal use of energy efficient glass, which is coated with a thin film to reduce heat loss. It has also been calculated that the EU could reduce carbondioxide emissions by a further 53 million tonnes if high-temperature superconductors were developed for use in power plants. At the same time, sales of energy-efficient products are generating significant income in this rapidly growing market. From 2010 to 2015, the global energy-efficient lighting market is projected to increase from $13.5 bn to $32.2 bn per year. General Electric estimates the potential

1907 H J Rounds of Marconi Labs discovers the phenomenon of electroluminescence.

1911 Dutch physicist Heike Kamerlingh Onnes discovers the phenomenon of superconductivity.

46 I IOP Institute of Physics

1927 Russian scientist Oleg Vladimirovich Losev reports the creation of the first LED.

1962 Nick Holonyak at the General Electric Company reports the first practical visible spectrum (red) LED.

1968 Monsanto mass produce red LEDs using gallium arsenide phosphide.

Today, 20% of the world’s electricity is used for lighting, and this could be reduced to four per cent with optimal use of LED lighting.

worldwide market for superconducting generators in the next decade is worth $20–30 bn. Another burgeoning market, phase-change materials, is expected to grow to $1.5 bn by 2015. Applications LED lighting LED light bulbs are now available to replace any standard household bulb. They use around six times less electricity than an incandescent light bulb, and 70% of the electricity of a compact fluorescent light (CFL) bulb. They can last for around 50,000 hours and have many advantages over CFLs – they use less energy, contain no mercury, have no vacuum, are more compact and can be controlled to produce light of any colour. They are particularly well suited to commercial and hospitality settings, where lights may be on almost continuously – here the payback time can be as short as one to three years. They are also now widely used in car headlights, aircraft lighting and traffic lights. If the UK were to replace all of its 25,000 traffic lights with LED bulbs it could save 50,000 tonnes of carbon dioxide and £16.7 m each year. LEDs are also proving useful for lighting supermarket freezer display cabinets, where they add less heat and perform better than fluorescent lighting, as well as being more attractive to customers. Power plants and transmission lines When electricity is generated in power stations with steam or gas turbines, at least 50%, and often as much as 70%, of the energy is lost as heat; and then yet more is lost (3% to 10%) along the electrical transmission and distribution lines to users. But, unlike copper wire, some materials are superconducting – which means that they transmit electricity with no resistance and no loss of heat. Superconductivity had been thought to occur only at the very lowest of temperatures (less than minus 260°C), but in the 1980s Nobel-prize winning research

1972 M. George Craford invents the first yellow LED and improves the brightness of red LEDs by 10 times.

1986 Georg Bednorz and K. Alex Müller observe high-temperature superconductivity in ceramic materials.

1987 Bednorz and Müller win the Nobel Prize in Physics for the discovery of high-temperature superconductivity.

1993 Shuji Nakamura of Nichia Corporation demonstrates the first high-brightness blue LED based on gallium indium nitride.

June 2013 Physics: transforming lives

I 47

Energy efficiency

led to the discovery of so-called “high-temperature superconductors” (HTSs). These still operate at low temperatures, but now less than minus 140°C, which could, in the future, make them a feasible supplement to traditional copper wire. However, high material costs and the cost of energy required to cool the superconducting transmission lines means they have to date only been used in some cases to replace short lengths of underground high-voltage cables to an installation. To transmit power for electricity over great distances, high-voltage DC (HVDC) power lines are currently one of the best available options. These have lower power losses than conventional AC transmission systems due to their greater capacitance, and take up less space than AC lines. Over long distances lower operating costs from reduced power losses makes HVDC an attractive option. Energy-efficient windows It was first demonstrated in the 1970s that a thin film of metal oxide could be deposited onto glass to make windows much more energy efficient. The technique used is called magnetron sputtering, which was first developed in plasma physics research. The windows have been widely used in the last two decades, and their uptake is growing rapidly, especially for new-build, where they are required by building regulations. In the UK, low emissivity, high solar gain windows are able to reduce heat loss by as much as 40% compared to standard double glazing. They work by transmitting sunshine and visible light, but blocking infra-red frequencies (heat), so reducing the amount of heat leaving a room. Coatings are also available that are more suited to hot climates to help keep homes cool in the summer. Heating and cooling materials The heating and cooling of buildings accounts for one third of all carbon-dioxide emissions globally. Phase-change materials (PCMs) are a recent innovation that is helping to significantly reduce the amount 1996 Nichia Corporation produces the first commercially available white LEDs.

48 I IOP Institute of Physics

2001 Philips Lumileds produces the first commercially available high-power white LED light bulbs for lighting.

2006 Superconducting transmission lines begin supplying power to 70,000 households in New York.

2010 UK-based Converteam install the first superconducting generator in a hydropower plant in Bavaria.

The heating and cooling of buildings accounts for one third of all carbon-dioxide emissions globally. Phase-change materials (PCMs) are a recent innovation that is helping to significantly reduce the amount of energy needed.

of energy needed. For example, a bioPCM gel being used in a new building in the University of Seattle has reduced the amount of energy needed to cool the building by 98%. UK-based Star Refrigeration is using carbon dioxide as a PCM, because it changes from a liquid to gas at a very low temperature, making it ideal for cooling computers in server farms. By piping carbon dioxide through heat exchangers, the company recently demonstrated that it could pull nearly twice as much heat from the computers as the systems used at present. In 2009 the market for PCMs was already worth $300 m. It is growing at a rapid pace and is set to reach $1.5 bn per year by 2015. Future Domestic appliances Advanced PCMs have the potential to help make appliances even more energy efficient. For example, it has been shown that PCMs can store the waste heat produced by a dishwasher in one cycle for use in a later one. Such a process has been shown to make dishwashers 22% more efficient. PCMs could be used to improve the energy efficiency of a wide range of domestic appliances, including dishwashers, washing machines, fridges, freezers and ovens. Smart dust Smart dust is a system of tiny microelectromechanical systems (MEMS) like sensors, each smaller than a snowflake, which can measure their environment and report back on changes. This could include monitoring even the smallest changes to big structures like bridges, or to monitor and automatically adjust lighting and temperature in buildings. Instead of a single thermostat for a whole room, thousands of these tiny devices – each less than a millimetre in size – could gather information from all over the building about where people are, how warm it is, how light it is, and then use this information to control lighting and heating in a smart way. 2012 Researchers at the University of Leipzig claim to have discovered a graphitebased material that is superconducting at room temperature and higher.

2012 Cambridge physicists develop a technique for growing LEDs on silicon, reducing the cost of manufacture five-fold.

June 2013 Physics: transforming lives

I 49

Energy efficiency

Facts and figures

$30 bn

36 mths the time taken historically for the efficiency

potential worldwide market for superconducting generators in the next decade

50,000 hrs

predicted market for phase change materials in buildings by 2020

and light output of LEDs to double

the lifetime of an LED light bulb

$265 bn predicted savings if US moves rapidly to LED lighting by 2027

85 m tonnes of carbon dioxide could be saved each year – 25% of the EU target – through the optimal use of low-emissivity glass by 2020

53 m tonnes potential reduction in carbon-dioxide

emissions in the EU if hightemperature superconductors were used in power plants

50 I IOP Institute of Physics

$1.5 bn

40 m tonnes possible reduction in annual carbon-

dioxide emissions in the UK from the switchover to LED bulbs


Detecting explosives and pollutants How UK-funded particle physics research is able to save lives during conflicts and help protect the environment.

The science Techniques used by physicists for detecting subatomic particles have led to a new chemical-monitoring system. DUVAS (Differential UV Absorption Spectroscopy), developed by Imperial College London physicists John Hassard and Mark Richards, and based on research funded by the UK’s research councils, chiefly the Engineering and Physical Sciences Research Council, and the Science and Technology Facilities Council, can rapidly detect Chemical Warfare Agents (CWAs) and Improvised Explosive Devices (IEDs), and provide real-time monitoring of airborne pollutants. It was commercialised via Imperial College London spin-out Duvas Technologies Ltd. The physics behind DUVAS DUVAS is based on UV spectroscopy, a technique that is able to identify different types of airborne atoms, molecules, and particles because they each absorb different wavelengths of UV light, and so produce dark lines in different places on a spectrum. The DUVAS system also uses special processing methods developed by particle physicists. Computers enable the subatomic particles created in particle-physics experiments to be represented by peaks in a spectrum of different masses, but these particles’ peaks will often overlap in that mass spectrum. Specialised processing separates out these overlapping peaks and so allows physicists to analyse the individual particles that caused them. This processing has to be incredibly fast as particles are created at a very high rate – around 200 m measurements must be taken every second. What physics does it rely on? −− Particle physics −− Molecular physics −− Statistical physics −− Computational physics −− Atmospheric physics −− Optics

June 2013 Physics: transforming lives

I 51

Detecting explosives and pollutants

Impact The DUVAS system can simultaneously detect over 20 different chemicals at a parts-per-billion level every few seconds, while its closest rival takes an average reading of just one type of chemical over a five-minute period. The ability to monitor several airborne chemicals in real time is important, as research suggests that short exposures to high concentrations of pollutants are far more damaging to health than longer exposures to low concentrations. The market for pollution-monitoring devices is significant – air pollution causes around three million deaths per year worldwide (30,000 of which are in the UK), while up to 10% of China’s GDP is lost due to air-pollution-related costs. In 2009, DUVAS’s technology was adopted by a major European defence company for CWA and IED detection. Almost 60% of UK armed forces deaths due to hostile actions since 2001 in Afghanistan have been caused by IEDs or landmines. Several countries have a range of CWAs available to them. Applications Protecting military personnel The DUVAS system can quickly and accurately sense ammonium nitrate explosives, and has passed trials for use in the defence sector detecting IEDs – which are usually made from ammonium nitrate. A major European defence company is now developing CWA detection systems, which will help protect soldiers and civilians from chemical weapons attacks, and is preparing to produce IED detection systems, based on the DUVAS technology platform. Meanwhile, Dutch independent research organisation TNO has validated the technology against a wide range of CWAs, paving the way for more generalised defence-sector sensors.

1996 Imperial College London’s John Hassard and colleagues receive funding from NERC, PPARC and EPSRC to develop the GUSTO system for air quality monitoring based on methods of detecting subatomic particles.

52 I IOP Institute of Physics

1999 The first GUSTO prototype system is created.

2003 Proof of principle established and further development of fixed roadside unit is carried out.

2006 Work starts on development of mobile unit as part of EPSRC funded MESSAGE programme.

The DUVAS system can simultaneously detect over 20 different chemicals at a parts-per-billion level every few seconds, while its closest rival takes an average reading of just one type of chemical over a five-minute period.

Detecting industrial pollutants DUVAS can be tailored to detect toxic industrial chemicals, and is being used by a major oil and gas company in South America for environmental monitoring – with the aim of stopping pollution – around oil pipelines. The system can also monitor for leaks and thus forewarn that action needs to be taken to stop the leakage before it causes an explosion. Duvas Technologies Ltd is also negotiating with two major oil companies for the use of its technology at petrochemical plants in the Middle East North Africa region, and with potential partners and distributors in China. Monitoring air quality Between 2010 and 2012, DUVAS systems monitored for pollutants produced through vehicle emissions at three primary schools in Brighton and Hove before, during, and after “Walk to School” week. The main purpose was to assess what impact Walk to School Week has on traffic emission levels and local ambient air quality. Project data are still being analysed, while several other district councils and municipalities, and the US Environmental Protection Agency, are also evaluating the technology. Future Currently 30 DUVAS air-quality monitors are being used at ports and airports worldwide, with a deal for hundreds of units being negotiated with a South American company in the petrochemical sector. Meanwhile for air-quality monitoring in urban areas, development work in conjunction with Imperial College London’s computing department has enabled DUVAS readings to be displayed over Google Earth maps and potentially be combined with weather and traffic information. The mapping of air-quality could aid town and congestion planning, as well as inform people with respiratory problems.

2008 The first mobile DUVAS system is created and Imperial College London spinout Duvas Technologies Ltd is founded to commercialise this technology.

2009 John Hassard, as founder of Duvas Technologies Ltd, wins the ‘Best of British’ category of the BBC Focus Innovation Awards.

2009 The DUVAS system undergoes testing for IED detection by a major defence company, who subsequently adopt the technology for their IED detection products.

2010 Imperial College London’s Mark Richards begins air quality monitoring projects, including analysing vehicle emissions in school playgrounds and nearby roads as part of the UK’s Walk to School campaign.

June 2013 Physics: transforming lives

I 53

Detecting explosives and pollutants

Facts and figures

± deaths worldwide are 3 m caused by air pollution each year. 30,000 of which are in the UK

< of China’s GDP is 10% lost due to air-pollution-related costs

±of UK armed forces 60% deaths due to hostile actions since 2001 in Afghanistan have been caused by IEDs or landmines

2010 Sales of DUVAS systems to the defence and security sector begin.

54 I IOP Institute of Physics

2012 Orders for hundreds of DUVAS units for the petrochemical sector being negotiated.

The DUVAS system can quickly and accurately sense ammonium nitrate explosives, and has passed trials for use in the defence sector detecting IEDs – which are usually made from ammonium nitrate.


Data storage

The Nobel prize-winning discovery by physicists made it possible to store vast amounts of data in tiny devices – creating the media revolution.

The science In 1988, physicists discovered a totally new phenomenon – “giant magnetoresistance” – in which very weak magnetic changes give rise to major differences in electrical resistance. This turned out to be the perfect tool for reading data from hard disks, converting information stored magnetically into electric current. How GMR increases data-storage capacity Each piece of information on a hard disk is stored as a microscopically small magnetic area. As hard disks get more compact and store ever more data, these magnetic areas get smaller and weaker. The phenomenon of giant magnetoresistance (GMR) enabled the development of ultra-sensitive read-out heads that are able to detect these tiny signals. The phenomenon was discovered thanks to techniques developed in the 1970s to produce very thin layers of matter. GMR only appears in layers of matter that are just a few atoms thick – so GMR is considered to be one of the first applications of nanotechnology. It also makes use of both the spin and the charge of the electron, making it the first application in the emerging field of spintronics. What physics does it depend on? −− Condensed-matter physics −− Quantum electronics −− Semiconductor physics −− Spintronics −− Electrostatic physics Impacts The global market for hard disk drives is currently around $38 bn. The hard drives of the 1980s and 1990s were used principally in computers as the main form of data storage, but, as they shrunk in size, new uses were found. Nowadays, compact hard drives are found in digital audio players (like iPods) and digital video recorders (like Freeview+ and Sky+ boxes), so it can be argued that this technology has brought about the digital media revolution.

June 2013 Physics: transforming lives

I 55

Data storage

Global online music sales are expected to reach $7.7 bn by 2015 as services like iTunes and Spotify gain momentum. Spending on CDs and other physical forms of music is expected to decline to $10 bn in the same period. In the UK, spending on digital music is expected to overtake physical music sales by 2015. The UK is at the forefront of this hard-drive industry, with a major Seagate Technology data storage plant and research and development centre located in Londonderry, Northern Ireland. Applications How have developments in physics increased data storage capacity in the past three decades? The discovery of GMR led to the development of the spin valve readout head, which enabled computer hard drives to store much more data in smaller spaces than had previously been possible. Hard drives were already steadily increasing in storage space, but this new technology led to a trebling in the annual rate of increase in capacity. Tunnel magnetoresistance – an extension of GMR – allows even greater sensitivity, and therefore even more compact hard drives, and has now replaced GMR in modern hard drives. The hard drives of the 1980s and 1990s were used principally in computers as the main form of data storage but as they shrunk in size new uses were found. Nowadays, compact hard drives are found in digital audio players (like iPods) and digital video recorders (like Freeview+ and Sky+ boxes) and games consoles such as a PlayStation. These innovations in turn have led to other transformative technologies. Without the existence of cheap hard drives capable of storing vast amounts of data, free search engines like Google would be impossible, as would free photo – and video-sharing websites such as YouTube,

1970s First techniques developed to produce very thin layers of material – a few atoms thick.

56 I IOP Institute of Physics

1988 Albert Fert and Peter Grünberg discover the phenomenon of GMR.

1989 Stuart Parkin of IBM develops the spin valve, based on the GMR effect.

1997 IBM commercialise the first spin valve read-out head for hard disks, enabling a 1000-fold increase in data density. This quickly becomes the standard technology for hard disks.

Nowadays, compact hard drives are found in digital audio players (like iPods) and digital video recorders (like Freeview+ and Sky+ boxes), so it can be argued that this technology has brought about the digital media revolution.

Flickr and Facebook. Free email with very large or unlimited storage capacity, such as Hotmail, Yahoo, Gmail, would also be impossible. The existence of digital audio players has led to a huge shift in the way that music is bought. Last year in the US, more music was bought online than on CDs for the first time, and the rest of the world is not far behind this trend. Services like iTunes and Spotify, in turn, rely on cheap, compact hard drives with enough capacity to store vast libraries of music. Movie libraries require even more storage capacity, and consumers are increasingly renting movies by downloading them straight to their televisions via video-on-demand services rather than renting DVDs or Blu-rays. Future The search is on for a successor technology that can combine high storage capacity with a high speed of operation. Currently, data is stored on hard drives or “flash memory” (a light-weight type of storage used in most smartphones), while a computer uses a different type – RAM – as its working memory. This is wiped clean when the power is switched off. A new “universal memory” would combine the speed of RAM with the storage capacity and stability of a hard disk and the lightness of flash memory. There are several promising contenders. British physicist Stuart Parkin of IBM, who developed the first spin valve read-out head, has led the development of two of these – magnetoresistive RAM (MRAM) and Racetrack memory. As its name suggests, MRAM also makes use of a magnetoresistance effect. The first commercial MRAMs were developed by Everspin, a Motorola spin-out company which has just brought an STT MRAM to market. This makes use of yet another spintronic effect, Spin Transfer

2004 Stuart Parkin of IBM and Shinji Yuasa of AIST, Japan, independently make junctions using tunnel magnetoresistance (TMR) that have double the capacity of GMR junctions.

2005 The first read-out heads using TMR instead of GMR are sold.

2007 Albert Fert and Peter Grünberg receive the Nobel Prize in Physics for their discovery of GMR.

June 2013 Physics: transforming lives

I 57

Data storage

Torque, to write the magnetic data using pulses of spin-polarised electrical current instead of a magnetic field. Racetrack memory stores information on magnetic nanowires just 15 nm thick. The first prototype Racetrack chip was showcased in December 2011. According to IBM this could lead to a new type of data-centric computing that allows massive amounts of stored information to be accessed in less than a billionth of a second. Other technologies in development that could form the basis of a new universal memory include ferroelectric RAM (FeRAM), phase-change memory (PCM), programmable metallisation cells (PMC) and resistive RAM (ReRAM). Each of these technologies is based on physics research of recent decades.

Facts and figures

$38 bn value of the global market for hard drives in 2012


the annual rate of increase in hard disk storage capacity trebled in the years following the commercialisation of GMR

10,000x more data is now stored on a typical hard drive than those before GMR

4 mb

the capacity of the earliest hard drives, which were the size of a large refrigerator and weighed nearly a tonne

4 tb

(4 million megabytes) the capacity of the latest hard drives, which are 20 cubic centimetres and weigh less than 50 grams


the date when spending on digital music sales is expected to overtake physical music sales

58 I IOP Institute of Physics

Satellite timing and navigation

Einstein’s discoveries underpin technology used by satellite-navigation systems, bringing major benefit to the UK economy.

The science A satellite timing and navigation system uses coded signals transmitted from orbit to radio receivers on Earth to provide accurate and precise timing references that are used to synchronise a variety of civil and military applications – such as financial transactions, control of utilities and determination of position and velocity. There are currently two operational Global Navigation Satellite Systems – the US Global Positioning System (GPS) and the Russian system GLONASS. Systems in China (Beidou) and Europe (Galileo) are under construction and expected to be available in 2015, and will provide improved accuracy and robustness. The physics behind satellite-navigation Accurate and extremely precise time-measurement is crucial to satellite-navigation, and requires the use of atomic clocks. These are the most accurate clocks available, and the first one was built at the UK’s National Physical Laboratory in 1955 by UK physicist Louis Essen. The difference in gravity between the satellite and the receivers on Earth means that timing corrections based on Einstein’s general theory of relativity are needed. Satellite timing and navigation systems use constellations of around 24 satellites in medium Earth orbits (around 22,000 km above the Earth). To pinpoint a location, a measurement of the distance between the user and at least three satellites is required. This is achieved by comparing the relative time of arrival of the three (or more) signals at the receiver by using a complex signal and coding structure. What physics does it rely on? −− Quantum mechanics and atomic physics −− Space science −− Satellite technology −− Atmospheric and solar science −− General relativity

June 2013 Physics: transforming lives

I 59

Satellite Timing and Navigation

Impact The impact of satellite timing and navigation can be quantified on two levels: that generated by companies directly involved in the provision and manufacture of the satellite and receiving technology, and the much wider impact of the many industries that now rely on its capabilities. The satellite-navigation industry itself made a valueadded impact contribution to UK GDP of around £113 m in 2010 and is expected to generate a value-added contribution to the UK worth £1.45 bn between 2011 and 2020. More broadly, the technology is a critical component of 21st-century telecommunications and transport systems, and the UK’s economy is increasingly dependent on satellitenavigation, with the GPS-sensitive portion of UK GDP being around seven per cent – or about £100 bn in 2010 prices. Applications Transport GPS, used for accurate navigation, is pervasive in our society, aiding road, air, sea and rail transport, providing improved safety, and optimised travel and planning. Satellite-navigation systems supporting fleet management contributed £2.3 bn to GDP in the UK in 2010, directly supporting 38,000 jobs and a further 48,000 jobs through the supply chain. Satellite-navigation systems saved the UK aviation industry £1.6 bn in 2010, by reducing delays, saving passenger time and lowering emissions through more efficient network planning. Precision-time measurements With its very reliable time signal, the GPS system is used to provide a very accurate measurement of time for terrestrial applications. Many areas of huge economic importance are dependent upon the GPS time signals – including financial services, computer systems, mobile communication, security and energy supply. Global stock trading

1916 Albert Einstein publishes his general theory of relativity.

1919 British physicist Sir Arthur Eddington observes the bending of light rays, as predicted by general relativity.

60 I IOP Institute of Physics

1955 UK physicist Louis Essen builds the first reliable atomic clock.

1960 The idea of a multi-satellite positioning system for land forces is proposed.

1978 The first GPS satellite is launched, equipped with an atomic clock.

Satellite Timing and Navigation

In 2010 the satellite-navigation industry made a value-added impact contribution of around £113m to UK GDP. It is expected to generate £1.45 bn between 2011 and 2020.

June 2013 Physics: transforming lives

I 61

Satellite Timing and Navigation

depends on precise timing – with shares being sold and bought for customers all around the globe, a fraction of a second of inaccuracy could cost millions as share prices fluctuate. It has been reported that a one-millisecond advantage in trading applications can be worth $100 m a year to a major brokerage firm. Currently, electronic trading comprises more than 80% of all trades. The routing of all internet traffic packets is reliant on GPS timing. Location-based services GPS navigation systems are incorporated into vehicles and built into mobile phones, expanding the potential of the GPS immensely. When combined with internet services, it becomes a significant aid to society and commerce, assisting the rise of personalised advertising services that many business models now depend on. Search-and-rescue operations also benefit substantially, as it can provide near real-time, precise location information between rescue centres and people in distress. It is estimated that the UK market size for location-based services is set to reach around £4 bn by 2020. Future At the request of the European member states, including the UK, the European Space Agency (of which the UK funds a €240 m annual share of the budget) is currently constructing its own fleet of satellites, named Galileo, to work alongside the existing American GPS, Russian GLONASS and the Chinese Beidou systems. With the market for satellite-navigation systems growing quickly, and becoming ever-more interlinked with the provision of services on which quality of life, health and safety depend, the need for an independent satellite-navigation infrastructure is becoming more important by the day. Galileo will help to guarantee the integrity of provision of such services in the future.

1993 The GPS is fully operational, giving worldwide coverage.

2004 A GPS navigation system costs less than £100.

62 I IOP Institute of Physics

2005 The first Galileo satellite, GIOVE-A, built by Surrey Satellite Technology Limited, is launched.

2008 GIOVE-B, is launched.

2008 GPSenabled mobile phones come onto the market.

The UK has been awarded £794 m worth of contracts associated with the Galileo project and stands to significantly benefit from the estimated 100,000 jobs that the programme is creating across the continent.

Galileo is to provide improved resolution on the current systems and is expected to be accurate down to one metre, while current GPS has an accuracy of around 10 m. It is expected that the system will reach initial operational capacity by 2015, with the complete network at full capacity before the end of the decade. The market worth of the Galileo project is expected to be around €10 bn a year. The UK is playing a significant role in Galileo. STFC’s RAL Space Department and Chilbolton Observatory played a significant role in the first two test satellites which were both constructed by UK companies in 2005 and 2008. This enabled UK industry to build all 22 navigation/timing payloads for the operational Galileo constellation. The UK’s ongoing involvement in Galileo has generated significant benefits for firms involved in both the provision and exploitation of satellite-navigation technology. The UK has been awarded £794 m worth of contracts associated with the validation and operational phases of the Galileo project, and stands to significantly benefit from the estimated 100,000 jobs that the programme is creating across the continent. Another Global Navigation Satellite System related project on the horizon is the replacement of the satellites in the current FORMOSAT-3/ COSMIC mission, used to assist with weather forecasting. The British company Surrey Satellite Technology Limited has been contracted to provide up to 22 new satellites, the first of which is intended to be launched in 2013, followed by the remainder through to 2018. The satellites will carry an advanced receiver, and information about the atmosphere will be collected by monitoring how it disturbs GPS signal. With all of its applications, this technology will continue to have a positive impact on the UK and global economy for many years into the future.

2009 Global Navigation Satellite Systems penetration in mobile phones worldwide reaches 15%.

2011 Launch of the first two operational satellites designed to validate the Galileo concept.

2012 Third and fourth operational satellites launched, making possible end-toend testing.

2020 Global Navigation Satellite Systems penetration in mobile phones worldwide expected to reach 65%.

2020 European Space Agency Galileo navigation system expected to reach full operational capacity.

June 2013 Physics: transforming lives

I 63

Satellite Timing and Navigation

The British company Surrey Satellite Technology Limited has been contracted to provide up to 22 new satellites, the first of which is intended to be launched in 2013, followed by the remainder through to 2018. The satellites will carry an advanced receiver and information about the atmosphere will be collected by monitoring how it disturbs GPS signal.

Facts and figures

£113 m

value-added impact contribution to UK GDP by satellite-navigation industry in 2010

£100 bn

GPSsensitive portion of UK GDP, around seven per cent, in 2010 prices

86,000 jobs supported directly and through the supply chain by satellitenavigation systems supporting fleet management

£794 m

value of contracts awarded to the UK associated with the validation and operational phases of the Galileo project

£4 bn

estimated to be the UK Global Navigation Satellite Systems market size for locationbased services by 2020

64 I IOP Institute of Physics

Case studies prepared by the Institute of Physics in partnership with the Engineering and Physical Sciences Research Council and the Science and Technology Facilities Council

For further information contact: Tajinder Panesor 76 Portland Place, London W1B 1NT Tel +44 (0)20 7470 4800 E-mail [email protected] Charity registration number 293851 Scottish Charity Register number SC040092 The report is available to download from our website and if you require an alternative format please contact us to discuss your requirements. The Kitemark is a symbol of certification by BSI and has been awarded to the Institute of Physics for exceptional practice in environmental management systems. Certificate number: EMS 573735