Seminar April 12 / 2011, ANSTO. Principle of AMS for 14C. Sample, ion beam.
14C ..... Thesis: Matthias Ruff. Combustion in Elemental. Analyzer. Sample wheel
.
Ion Beam Physics
From large AMS facilities to table size instruments Martin Suter Ion Beam Physics, ETH Zurich, Switzerland
ETH 2011
Rochester MP-Tandem, 1977 Mc Master University, 1977
Voltage: Energy: Length: Costs:
6-10 MV 30-50 MeV 40 m 10 M€
Seminar April 12 / 2011, ANSTO
Voltage: Energy: Length: Costs:
0.04 MV 0.04 MV 2.0 m 0.8 M€
Martin Suter
∼ 200 x ∼ 1000x ∼ 20 x ∼ 12 x
Page 1
Ion Beam Physics
AMS development at ETH Zürich Tandy: 0.55 MV Pelletron (NEC)
EN 6MV-Accelerator built 1960-1964
Multi-isotope
3x4m
1995-2009 10Be, 14C,26Al,41Ca,129I,Pr,236U,
2000-2010 ETH/PSI: MICADAS, 200 kV, 14C
Pu;
2010-2014 ETH Zurich Radiocarbon MS, 45 keV
Modified for AMS 1979-1984 10Be,14C,26Al,32Si,36Cl,41Ca,129I
Seminar April 12 / 2011, ANSTO
2x2m
Martin Suter
Page 2
Ion Beam Physics
Organisation of the Laboratory of Ion Beam Physics
Physics-Department Institute of Particle Physics
Application groups
Scientific Board with representatives from
D-PHYS, IPP, D-ERDW, EAWAG, EMPA, PSI
Head LIP Scientist, D-PHYS
Ion Beam Physics Instrumentation
Materials Research with Ion Beams
Seminar April 12 / 2011, ANSTO
AMS Applications
Martin Suter
Technical Support Page 3
Ion Beam Physics
Laboratory of Ion Beam Physics (LIP) Physics Department, ETHZ Staff working on instrumentation
Head: Dr. Hans-Arno Synal Research Scientists: 7 Post. Docs: 4 PhD Students: 3 Techn. Staff 13 Administration 1 Retired (Scienists) 2 ___________________________ Total ~30 ========================== Guests 0-4 Students 0-3
Seminar April 12 / 2011, ANSTO
Compact Radiocarbon 40- 200 kV
Tandy 550 kV
Technical staff for instrumentation: 10
Martin Suter
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Ion Beam Physics
Sample Statistics LIP
~7500 in 2010
with 3 accelerators, 6 MV, 550 kV, 200kV Seminar April 12 / 2011, ANSTO
Martin Suter
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Ion Beam Physics
1979 - 1991: 1991 - 2008: May 2008 2008- 2011
AMS at ETH Head of Laboratory of Ion Beam Physics, Professor in Department of Physics Early retirement Participating in some projects at ETH
Martin Suter
Sevilla, Spain 6 months
AMS Vienna, Austria 2 months AMS Peking University China 2 weeks Aster, Aix, France 3 months
Seminar April 12 / 2011, ANSTO
Martin Suter
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Ion Beam Physics
My interest and my dreams
-Smaller -Cheaper -More reliable -High performance -Universal
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 7
Ion Beam Physics
Computer development (1970-2010) PDP-15, 1970
Memory: 64 kB Harddisk : 5 MB Clock: 20 MHz Volume: 0.8 x 2 x 4 =6.4 m3 Seminar April 12 / 2011, ANSTO
2010
Memory: 64 GB, Clock:1GHz Volume: 0.0006 m2 Martin Suter
Page 8
Ion Beam Physics
Moore‘s Law
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 9
Ion Beam Physics
AMS: Reduction of Energy Destruction of molecules by collisions, 1+,2+
Energy 14C-Measurements: 1977 40 MeV 1984 9 MeV 1998 1 MeV 2002 0.4 MeV 2011 0.045 MeV
He-Stripping
t1/2=3.5 years
Voltage (Stripping Energy) 1977 8.0 MV 4+ 1984 2.2 MV 3+ 1998 0.5 MV 1+ 2002 0.22 MV 1+ 2011 0.045 MV 1+
Energy 10Be 1980 40 MeV 1984 5.3 2008 0.75
Seminar April 12 / 2011, ANSTO
Martin Suter
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Ion Beam Physics
How can we make better and smaller Instruments for AMS? Physics
Physis of AMS: Existing models Not good enough ! Existing data Not good enough!
Technologies Ideas
⇒ Better models ⇒ New data
New technologies: Materials (SiN-foils) Components (pumps) Power supplies Electronics
Ideas: New concepts New methods New designs Improved Methods
Finances + Infrastructure => New Instruments/ better performance/ cheaper/ smaller AMS-12- Topic: Technical Advances, Non-standard AMS isotopes (NOT PHYSICS) Seminar April 12 / 2011, ANSTO
Martin Suter
Page 11
Ion Beam Physics
What kind of physics? Ion Beam Physics (keV - MeV) Ion- Atom Collisions: Scattering, Ionisation, Electron transfer
Ion- Molecule Collisions
Ion gas & solid interactions
Ion interaction with electric and magnetic fields (ion optics) Seminar April 12 / 2011, ANSTO
Martin Suter
Page 12
Ion Beam Physics
Principle of AMS for 14C 100 Atoms/sec of 14C
2 10+14 Atoms/sec, 32 μA of C Sample, ion beam
14C
14C
14C
14C
14C
Filter
Filter
Filter
Filter
Filter
Negative Ion source Isobar Separation
Seminar April 12 / 2011, ANSTO
Massspectrometer mass separation
Particle Accelerator destruction of molecules
Massspectrometer mass separation
Martin Suter
Detector isobar separation
Page 13
Ion Beam Physics
Tandem accelerators: Size and Voltage 16
12
Length m
~ Price in M€
14
10
Power Supply (Tandtron, HV) Pelletron, NEC
8
Large and Extra Large
6 4 2
Medium Small and extra small 2
Seminar April 12 / 2011, ANSTO
4 6 Terminal Voltage in MeV
8
Martin Suter
10
Page 14
Ion Beam Physics
Charge state yield and accelerator size Carbon in Ar
1+
2+
3+ 4+
q > 2 molecules unstable q < 3 molecules stable
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 15
Ion Beam Physics
Destruction of molecules in the stripping process 13CH, 12CH
2,
7Li
2
1) Stripping to q >2:
complete destruction
2) Stripping to q < 3 Destruction in collisions: Reduction of intensity Number of detected ions @ mass 14 amu
1'000'000
100'000
I=I0 e-σd
10'000
Jacob Lee
1'000
100
10
A.E. Litherland, NIM B5(1984)100; Lee NIM B5 (1984)208
1 0.00
0.20
0.40 0.60 0.80 1.00 Stripper thickness / µg /cm2
1.20
Intensity of CH+ has to be reduced by 11 orders ! Seminar April 12 / 2011, ANSTO
Martin Suter
Page 16
Ion Beam Physics
Construction of a compact AMS facility by ETH/PSI In collaboration with NEC (accelerator company, USA) 1999: Carbon dating is possible at 0.4 to 0.5 MV Nucl. Instr. and Meth. B172 (2000) 1 (IBA-19 )
4m Background: 14C/12C = 0.1 - 0.6 *10-14 Accuracy: 0.3-0.5 % Transmission: 40 -50 % =>
Almost equivalent in performance compared to larger facilities (2-6 MV)
6m
Other developments at the same time: Newton Scientific , HVEE Seminar April 12 / 2011, ANSTO
Martin Suter
Page 17
Ion Beam Physics
Further developments : 2000-2010
Smaller instruments for radiocarben
Compact multi isotope Instruments: 10Be, 26Al, 41Ca, 129I, 236U, 239,240 Pu
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 18
Ion Beam Physics
Is a „universal“ AMS system with compact 500 kV possible? 1) Problems: small angle scattering 2) Yield (Stripping, Scattering) 3) Detection identification of isobars
Examples:
10Be-10B 238,239Pu
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 19
Ion Beam Physics
Prinziple of an Ionizations Chamber used in AMS HV ~ 100 V
d Settings \suter \My Documents \Jan04 \DPGMü nchen \be
00
ΔE
Eres Anode(s)
80
60
40
20
0 0
20
40
60
80
100
Multichannelanalyser E ∼ Q = q x (E / EI) EI = 20 – 40 eV for Gases EI = 3.6 eV for Si
Entrance foil
Cathode
Seminar April 12 / 2011, ANSTO
(Frisch-)-Grid
Signals are factor 10 smaller 1 MeV → 2 - 4 10+4 Electrons Martin Suter
Page 20
Ion Beam Physics
Detector development 1) Energy reduction in entrance window 2) Energy resolution 3) Pulse height (and defect) 4) Isobar separation
Isobar separation at low energies : 10Be- 10B 240Pu3+ - 160Dy2+, 80Se1+ M/q Ambiguities :
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 21
Ion Beam Physics
Detector development Entrance window SiN-foil 34 nm (2002)
Detector resolution: 1) Entrance window 2) Electronics 3) Gas 4) Geometry, field configuration
Electronics Low Noise Cooled FET (2005)
Design Compact Good shielding 2005
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 22
Ion Beam Physics
Energy straggling in foil: 34 nm Si3N3.1: Results and Model
Energies: 0.4 MeV 0.8 MeV 1.2 MeV 1.6 MeV
Yang model is in good agreement with the experiments ! Seminar April 12 / 2011, ANSTO
Martin Suter
Page 23
Ion Beam Physics
Energy resolution for light ions (m light element ? Nobel gases?
- Destruction of molecules ?
=> light element???
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 50
Ion Beam Physics
Stripping yield of C on He
?
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 51
Ion Beam Physics
SRIM- Simulations Transmission for 12C in N2,He (point source)
30 mrad
15 mrad
Seminar April 12 / 2011, ANSTO
C in He (30 mrad) C in He (15 mrad) C in N2 (30 mrad) C in N2 (15 mrad)
Martin Suter
Page 52
Ion Beam Physics
Destruction of CH and CH in He and N2
Tim Schulze-König Ph.D. Thesis (2010)
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 53
Ion Beam Physics
First results of MS of 14C (Feasibility study)
Stripping yield: Overall transmission: Background: Reproducibility (mod C):
75 % 35-40% 0.5 pMC 1.2 %
Also studied - Background sources - Charge changing cross sections
45 keV Seminar April 12 / 2011, ANSTO
- Beam phase space
Martin Suter
Page 54
Ion Beam Physics
Developing of Radiocarbon MS Optimizing Stripper Optimizing Optics Optimizing Pumping Optimizing Apertures Optimizing Detector
Seminar April 12 / 2011, ANSTO
Instrument for routine operation in 2-5 years
Martin Suter
Page 55
Ion Beam Physics
He-stripping of heavy ions
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 56
Ion Beam Physics
Advantages of He stripping for U
37%
3.3 x
11%
1) Higher yield at low energies 2) Lower scattering losses Seminar April 12 / 2011, ANSTO
Martin Suter
Page 57
Ion Beam Physics
Mean charge Width of distribution
Folien
Gase
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 58
Ion Beam Physics
Angular distribution for U in He based on SRIM Simulations Scattering Limit: 16.8 mrad = mHe/mU= 4/238
Seminar April 12 / 2011, ANSTO
Thickness μg/cm2 0.02 0.08 0.12 0.2 0.6
Martin Suter
Page 59
Ion Beam Physics
Charge State Distribution of U in He What is the highest yield ?
Wittkower ETH
Estimate for the maximum: 46-48 % at 500-600 keV
Seminar April 12 / 2011, ANSTO
Martin Suter
Page 60
Ion Beam Physics
Compact multi-isotope AMS 600 kV compared to large facilities) ETHZ Isotope Beam Background10-14 Trans/Yield (%) Energy ETHZ 5-8 MV ETHZ 5-8 MV ETHZ 5-8 MV ok 10Be
BeO
0.1
