ISSN 00204412, Instruments and Experimental Techniques, 2014, Vol. 57, No. 1, pp. 1–10. © Pleiades Publishing, Ltd., 2014. Original Russian Text © A.V. Kantsyrev, A.A. Golubev, A.V. Bogdanov, V.S. Demidov, E.V. Demidova, E.M. Ladygina, N.V. Markov, V.S. Skachkov, G.N. Smirnov, I.V. Rudskoy, A.P. Kuznetsov, A.V. Khudomyasov, B.Yu. Sharkov, S.V. Dudin, S.A. Kolesnikov, V.B. Mintsev, D.N. Nikolaev, V.Ya. Ternovoi, A.V. Utkin, D.S. Yuriev, N.S. Shilkin, V.E. Fortov, V.I. Turtikov, V.V. Burtsev, M.V. Zhernokletov, N.V. Zavialov, S.A. Kartanov, A.L. Mikhailov, A.V. Rudnev, M.V. Tatsenko, D.V. Varentsov, L.M. Shestov, 2014, published in Pri bory i Tekhnika Eksperimenta, 2014, No. 1, pp. 5–14.
NUCLEAR EXPERIMENTAL TECHNIQUES
TWACITEP Proton Microscopy Facility A. V. Kantsyreva*, A. A. Golubeva, A. V. Bogdanova, V. S. Demidova, E. V. Demidovaa, E. M. Ladyginaa, N. V. Markova, V. S. Skachkova, G. N. Smirnova, I. V. Rudskoya, A. P. Kuznetsova, A. V. Khudomyasova, B. Yu. Sharkova, b, S. V. Dudinc, S. A. Kolesnikovc, V. B. Mintsevc, D. N. Nikolaevc, V. Ya. Ternovoic, A. V. Utkinc, D. S. Yurievc, N. S. Shilkinc, V. E. Fortovc, V. I. Turtikovd, V. V. Burtseve, M. V. Zhernokletove, N. V. Zavialove, S. A. Kartanove, A. L. Mikhailove, A. V. Rudneve, M. V. Tatsenkoe, D. V. Varentsov f, and L. M. Shestov f a
Institute for Theoretical and Experimental Physics (ITEP), ul. Bol’shaya Cheremushkinskaya 25, Moscow, 117218 Russia *email:
[email protected] bFacility for Antiproton and Ion Research (FAIR) in Europe GmbH, Planckstrasse 1, Darmstadt, 64291 Germany cInstitute of Problems of Chemical Physics, Russian Academy of Sciences, pr. Akademika Semenova 1, Chernogolovka, 142432 Russia dFoundation for the Development of the Center for Elaboration and Commercialization of New Technologies (Skolkovo Foundation), Krasnopresnenskaya nab. 12, Moscow, 123610 Russia eRussian Federal Nuclear Center, AllRussia Research Institute of Experimental Physics, pr. Mira 37, Sarov, Nizhni Novgorod oblast, 607188 Russia f GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, Darmstadt, 64291 Germany Received May 7, 2013
Abstract—A proton radiography facility with the use of magnetic optics (PUMA proton microscope) has been developed at the TWACITEP accelerator–accumulator facility (the ITEP terawatt accumulator) for measuring the substance density distribution inside static and dynamic objects using the proton beam with an energy of 800 MeV. The proton radiographic image of an object of investigation placed in the object plane of the setup is formed in the plane of the detector with magnification K = 4 with the aid of the magnetooptical system consisting of four quadrupole lenses on permanent magnets. The PUMA facility is intended for mea suring objects with an areal density of up to 20 g/cm2 with a field of vision as large as 20 mm in diameter. The spatial resolution of radiographic images depends strongly on the areal density of the object of investigation. For the PUMA facility, the spatial resolution varies from 60 to 115 µm at an areal density of 0.46–17 g/cm2, respectively. The dynamical state of substance can be investigated in four consecutive radiographic images, since the time structure of the proton beam consists of four pulses, each with a duration of 47 ns (full width at half maximum (FWHM)) and an interval of 250 ns between them. This article is devoted to the description of the proton microscope construction. The main metrological characteristics of the facility are described using experiments with static and dynamic objects as an example. DOI: 10.1134/S0020441214010151
INTRODUCTION
The aim of this work is to develop a proton radiog raphy facility with magnetic optics (proton micro scope PUMA) at the proton accelerator of the ITEP. This facility will be used to measure the density distri bution in static and dynamic objects while carrying out basic and applied research in the fields of high energy density physics, radiobiology, and materials science.
Radiographic facilities existing at proton accelera tors in the United States [1, 2] and Russia [3–5] have vividly demonstrated the advantages of the proton radiography method over the traditional radiographic diagnostic techniques in investigations of dense objects, particularly, in dynamic experiments. The best spatial resolution for proton radiography has been obtained at facilities with the image magnification, which embody the proton microscope principle [2]. By the present time, there have been no analogs of such facilities in Russia.
A MAGNETOOPTICAL SYSTEM OF THE PROTON MICROSCOPE The scheme of the proton microscope comprising quadrupole lenses based on permanent magnets (the 1
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2
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Sample under investigation
4
I
Fourier plane
5
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T C Matching system
Image formation system
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Fig. 1. Layout of the magnetic elements and the beam trajectory of the PUMA proton microscope.
permanent magnetic quadrupoles) was implemented for the first time at the LANSCE accelerator (United States) [2]. The PUMA proton microscope was built on the fast proton beamline at the TWACITEP accelerator– accumulator facility [6]. It is a part of the multipur pose experimental complex PRIMA. The design of the PUMA facility had to solve the problem of disposing the proton microscope components on the same beamline in which the first dynamic experiments were formerly performed using the proton radiography facility with the quadrupole electromagnetic lenses [3]. For this problem to be solved, it was proposed using permanent magnet quadrupoles (PMQs) featur ing a high magnetic field gradient at small geometrical sizes. The magnetic optics of the entire facility is a system of seven magnetic quadrupole lenses (see Fig. 1). Three МЛ15 electromagnetic quadrupole lenses 1–3 ensure optimal parameters of the proton beam (its size and angular characteristics) in the plane T of the object under investigation and partially compensate aberrations of the facility. A system of four PMQs 4–7 is used to form and magnify the image of an object in imaging plane I. The image sharpness is tuned by longitudinal PMQ dis placement. The magnetic optics of the proton micro scope has been designed so that socalled Fourier plane C is formed in the middle of the measuring sec tion, between lenses 5 and 6. It is in this plane that intermediate beam focusing proceeds, along with spa tial separation (by the distance from the beam axis) of protons that acquired different angles of multiple Coulomb scattering (MCS) in the analyzed sample. A collimator improving the sharpness of recorded images or an anticollimator selecting protons with a certain MCS angle is placed at this point. The density inside the sample under investigation is determined after processing radiographic images obtained by recording, using CCD cameras, and light emitted by the scintillator located in the detection plane. The procedure of proton radiographic image processing is presented in Fig. 2. At the first stage of processing, the “black background” (the image
recorded by the CCD camera in the absence of the beam) is subtracted from the recorded proton radio graphic image. This allows defects of the image due to operation of the CCD camera to be compensated. In what follows, we divide a recorded image into the “white field” image obtained in the absence of the beam, from which the black background image was also subtracted. This allows us to eliminate the contri bution made to the resultant image by defects in the scintillator and the optical imaging system and by irregularities in the transverse section of the beam. As a result, we obtain an image of the object of investigation in terms of the proton beam transmis sion. Its value in the detection plane is determined by the processes of nuclear interaction and MCS inside the object. The beam transmission dependent on the nuclear interaction processes can be presented by the expression [1]:
Tnucl = e −x / λc ,
(1)
where x [g/cm2] is the areal density of the object of investigation, and λc is the nuclear interaction length. The equation for the beam transmission deter mined by the processes of Coulomb scattering in the object of investigation can be written in the form [1]
Tmcs = 1 − e
−θ2c 2θ2
,
(2)
where θс is the angular acceptance of the facility deter mined by the collimator diameter, θ is the mean MCS angle, the value of which is determined by the expres sion [7]:
θ=
13.6 MeV x ⎡ ⎤ 1 + 0.038 ln x ⎥ , ⎢ pβ c x0 ⎣ x0 ⎦
(3)
where х0 is the radiation interaction length, p is the beam particle momentum, βс is the proton beam velocity with reference to speed of light с. The resultant beam transmission in the measure ment plane is
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Black background
–
=
Subtraction
/
=
Division
“While field”
Proton beam transmission
Fig. 2. Procedure for radiographic image processing.
θc pβ c x0 ⎞ ⎛ ( ) ⎜1 − e 13.6 2x ⎟ . ⎜ ⎟ ⎝ ⎠ 2
T =e
−x / λc
(4)
Parameters λc and х0 depend on the chemical com position of the sample. Parameter θc helps tune the optimum sharpness of images by varying the collima tor diameter. Therefore, measuring the beam trans mission, we can determine areal density x of the sam ple from Eq. (4) with allowance for the knowledge of its chemical composition. If the geometry of the sam ple is known, it is possible, using the x value, to calcu late the volume density of the object.
CALCULATING THE ION OPTICS OF THE PROTON MICROSCOPE The magnetic optics of the microscope was calcu lated in [3] using the COSY INFINITY program [8]. The proton microscope was tuned to magnification K = 4. The direction of the fields in the quadrupole lenses alternates in the following sequence: D – F – D – F – D – F – D, where F and D denote the proton beam focusing and defocusing by the quadrupole lenses in the vertical plane. The matrix formalism of magnetic optics system representation is used to describe the quadrupole lens scheme. For the beam particles with momentum spread Δ = dp/p in the plane of the sample with initial
Vacuum chamber with the sample under investigation Scintillator
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Sliders
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Computer САМ01
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Fig. 3. Hardware scheme of the PUMA proton microscope. INSTRUMENTS AND EXPERIMENTAL TECHNIQUES
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Linear manipulator
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Fig. 4. External appearance of the facility—the PUMA proton microscope.
coordinates (x, ϕ), the final coordinate in the mea surement plane is
x f = M 11 x + M 12ϕ + T116 x Δ + T126ϕΔ ,
(5)
where M11, M12, T116, and T126 are the transport matrix coefficients; M 11 is the magnification of the radio graphic facility; M 12 = 0 is the imaging condition in the measurement plane; and T116 and T126 determine the chromatic aberrations of the magnetooptical sys tem of the facility. The effect of the term T116 xΔ (“the transverse chro matism”) is excluded from Eq. (5) by using the match ing system (lenses 1–3 in Fig. 1), which ensures the angular correlation [3] of the original proton beam: ϕ = wx + θ, where w = −T116 / T126. In this case, Eq. (5) is transformed so that
x f = M 11 x + T126θΔ .
The dot gain in the measurement plane, which is directly related to the spatial resolution of radio graphic images, is
(6)
Δx f =
xf T − x = 126 θΔ . M11 M11
(7)
Coefficient T126 (the “longitudinal chromatism”) should be minimized in the course of calculation by the COSY INFINITY program. From Eq. (7), it is apparent that development of a proton radiography facility with the magnification (of its proton micro scope) makes it possible to substantially improve the spatial resolution of radiographic images. HARDWARE OF THE EXPERIMENTAL FACILITY A lutetium silicate (LSO) scintillator with a thick ness of 4 mm and a diameter of 80 mm is used as a
Permanent magnets
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Yoke
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Fig. 5. (a) Isolated module of the quadrupole lens for the proton microscope and (b) ready PMQs for the proton microscope. INSTRUMENTS AND EXPERIMENTAL TECHNIQUES
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beam detector and a means for radiographic imaging. The temporal profile of the proton beam consists of four pulses, each with a duration of 47 ns (FWHM) and an interval between pulses of 250 ± 5 ns. The spill frequency is ≤0.25 Hz. This allows as many as four images to be obtained in the investigation of the dynamic process. A fourpattern recording system was developed for storing radiographic images. This sys tem is based on fast digital CCD cameras (CAM05– CAM08 in Fig. 3) S2C077FOG (NTTs SILAR, St. Petersburg) with electronic shutters (dynamic range, 14 bit; exposure time, 100 ns). The position and transverse profile of the beam are measured using SDU285 CCD cameras (Spets teletekhnika, Moscow) CAM01–CAM04 with Bicron BC412 scintillators remotely installed on the beam axis. A Bergoz FCT08205:1 fast current transformer is used to measure the temporal profile of the proton beam pulse and control synchronization of triggering of the recording channels. The PMQs are moved by a system of four linear manipulators consisting of NB BG2602A300H/A5CLB linear actuators and FL42STH step motors featuring an accuracy of 50 μm. Four PMQs are installed on a common rail and are displaced by the linear actuators mounted on both sides of the rail. The range of displacement of each magnetic quadrupole lens is 250 mm, and the speed is 1 mm/s. A controller based on an LCARD E14140 USB module is used to control the PMQ manipulators. The PROTOM program has been developed in the Delphi environment to control PMQ movement from a per
G, T/m 30 20 10 0
Radiographic image of the static target
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0 z, m
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Fitting with the polynomial of the fourth degree (Calculating coefficients А, B1–B4)
SDUITER/DiCam Program for reading out images from the CCD camera
PROTOM Program for moving the PMQs
Constructing the profile Minuit Minimizing by HFWHM with variation in the tuning beam energy value
Fitting with the Gaussian function
Fig. 7. System of automatic focusing of radiographic images. INSTRUMENTS AND EXPERIMENTAL TECHNIQUES
0.08
sonal computer. This program allows fixing of the PMQs in a required position both manually and in the automatic mode. Triggering of the data acquisition channels is syn chronized from the Stanford DG645 and DG535 dig ital delay and pulse generators. A threecoordinate vacuum manipulator has been developed for position ing objects of investigation relative to the beam with an accuracy of 10 μm. The manipulator design is based on linear and rotary translators from Standa. A vac uum manipulator has been designed for placing colli mators with different diameters at the beam axis. Data readout and control of all facility components are per formed from remote personal computers using the complex experiment automation system [6]. A vac
Differentiating
(a)
–0.04
IG, T 2.4 2.0 1.6 1.2 0.8 0.4 0
Fig. 6. Longitudinal distribution of gradient G and gradient integral IG of the magnetic field of an assembly composed of two quadrupole modules (the total length is 80 mm).
Calculating the PMQ positions in the COSY INFINITY program (Obtaining the dependence of the PMQ positions on the tuning beam energy)
Beam Control Program controlling the beam spill
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330
340
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360 x, μm
Fig. 8. Proton radiographic image profile (in terms of transmission) of an edge of 550µmthick brass plate recorded by the PUMA proton microscope.
uum explosionproof chamber has been produced for experiments with dynamic objects, tested, and certi fied for multiple uses of explosives. The external appearance of the developed PUMA proton micro scope is shown in Fig. 4.
magnets are inserted directly in the magnet yoke made from magnetically soft iron. Taking into account the vacuum system design, the resultant aperture of the proton microscope is 32 mm. The distribution of the magnetic field and the main characteristics of the PMQs were measured using the scanning test bench produced on the basis of the com plex experiment automation system at the PRIMA setup [6]. A Hall sensor (ПХЭ 606118A) connected to the Agilent 34970A highprecision data acquisition and switch unit was used to measure the magnetic field. The sensor was moved by means of Standa 8MT175 linear stages and 8MR151 rotation stages. The accuracy of the sensor’s linear displacement is 2.5 μm, and the angular accuracy is 0.6´. The field was scanned both over the cylindrical surface near the lens aperture radius with the aim of determining the whole field pattern inside the aperture, and along the lens axis at two identical distances from it in order to deter mine the gradient characteristics of the modules. The magnetic field measurement accuracy is 0.1%. Figure 6 presents the measured values of field gradient G and integral of the gradient IG of the magnetic induction in the paraxial region (±2 mm from the axis) of the assembly composed of two modules with a total length of 80 mm. The reduced value of the field at the PMQ pole is 0.578 T, the PMQ field gradient is G = 28 T/m. AUTOMATIC FOCUSING SYSTEM OF RADIOGRAPHIC IMAGES
PERMANENT MAGNET QUADRUPOLES OF THE PROTON MICROSCOPE The dimensions of the PMQs used in the imaging system are as follows: the length of lenses 4 and 7 (Fig. 1) is 160 mm, the length of two inner lenses 5 and 6 is 320 mm, the aperture is 40 mm, and the magnetic field at the pose is 0.6 T. The PMQs used in the proton microscope consist of identical modules. Each mod ule is a 40mmlong quadrupole (Fig. 5a) composed of permanent magnets (Nd–Fe–B). The permanent
(a)
(b)
In the course of proton radiography experiments, it is necessary that precise tuning of the ion–optical sys tem be performed in accordance with the areal density of analyzed samples and the beam energy. In this case, the proton microscope is tuned so that the highest sharpness of radiographic images is attained. To accel erate the process of proton microscope tuning and obtain the highest spatial resolution, an automated system of radiographic image focusing has been devel oped.
(c)
Fig. 9. (a) Photo of the “cube with slits” brass sample 20 mm thick and radiographic images of the sample obtained (b) at the facility without the magnification and (c) at the PUMA proton microscope. INSTRUMENTS AND EXPERIMENTAL TECHNIQUES
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Stainless steel
Brass
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Proton beam Reconstructed image of the transverse section
ART Rotating manipulator
Fig. 10. External appearance of the cylindrical sample (left), layout of the experiment on the threedimensional reconstruction of the internal structure of a static object (at the center), and transverse section of the cylinder reconstructed by 90 radiographic projections (right).
This system uses three firmware modules [6], which include the following programs: PROTOM for transportation of the PMQs; SDUITEP [6] for read ing radiographic images from the SD285 CCD cam eras and their processing; and BeamControl [6] for controlling beam spills. The firmware modules are integrated into a unified ring computing network with the use of the TCP/IPSockets network protocol. The diagram of program interactions in the system of auto matic focusing of radiographic images is shown in Fig. 7. The automatic focusing system operates as follows: —prior to beginning an experiment, optimal posi tions of all four PMQs are calculated using the COSY INFINITY code for several tuning values of the beam energy at the exit from the sample, which corresponds to several values of the mass thickness of the object; —based on the calculated dependences of the PMQ coordinates on the tuning energy, the fitting function is calculated in the form of a polynomial of the fourth degree xi = Pi 4 (E ), where xi is the PMQ coordinate, i is the PMQ number, and E is the tuning energy. The type of the function is selected by the best coincidence with the initial data of the coordinates and energies. The calculated coefficients of the poly (a)
TNT
nomials are entered into the PROTOM program. Using the values of the input proton energy, the PRO TOM program calculates the initial PMQ coordinates. Using the linear manipulators, the PMGs are set in positions with these coordinates; —the mode of automatic beam spill control is acti vated in the BeamControl program, and the beam is spilled from the accelerator; —in the SDUITEP program, the radiographic image of the object is read out, the scintillator emis sion profile at the sharp edge of the object is plotted (the object is vacuum), the plotted profile is differenti ated and fitted with the Gaussian function, and the full width at half maximum HFWHM is calculated; —using the Minuit script [9], HFWHM parameter is minimized by cyclically changing the tuning proton beam energy in the PROTOM program and processing the obtained profiles of the radiographic images. The process of PMQ tuning and attaining of the best spatial resolution requires ~30 beam spill itera tions (~10–15 min) and proceeds completely in the automatic mode. This accelerates the procedure for tuning the proton microscope substantially, more than 10 times.
(b)
(c)
V = 6.9 km/s
∅10 mm
Detonation wave
Fig. 11. Radiographic images of the detonation wave in the cylindrical TNT charge 10 mm in diameter: (a) static image of the sample and (b, c) images of the charge upon detonation for two sequential beam bunches with a 250ns difference in time. INSTRUMENTS AND EXPERIMENTAL TECHNIQUES
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1.9 1.8 1.7 1.6 1.5 1.4
4
6
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10 12 14 Vertical coordinate, mm
Fig. 12. Profiles of the detonation wave front in the TNT sample obtained from two radiographic images recorded with a 250ns time interval.
EXPERIMENTAL RESULTS Static Objects The limiting resolution of the PUMA facility was measured at pressure P < 10–4 Torr in the vacuum chamber of the facility for a static object—a brass plate 550 μm thick (its areal density is 0.46 g/cm2) placed perpendicularly to the proton beam. By the spatial resolution of the facility, we mean smearing of a sharp boundary of the sample–vacuum image, which is described by the width of the fitting Gaussian distribution. The radiographic image profile of the plate edge is shown in Fig. 8. The fit of the profile with the integral of the Gaussian function is presented with a curve. The obtained resolution of the PUMA facility that embodies the proton microscope principle with magnification K = 4 is σ = 60 ± 5 μm for an aerial density of 0.46 g/cm2. For comparison, Fig. 9 presents examples of radio graphic images obtained with the PUMA proton microscope at the radiographic facility without the magnification [4]. For a brass cube 20 mm thick (its areal density is 17 g/cm2), the spatial resolution is σ = 115 ± 5 μm, which is significantly better than the lim iting resolution of 300 μm obtained at the radiographic facility without the image magnification (K = 1) [3, 4]. A set of experiments aimed at studying the internal structure of test biological samples were carried out at the PUMA proton microscope [10]. Their results demonstrated the applicability of the proton radiogra phy technique for therapeutic irradiation of tumors with highenergy protons. Data of these experiments will be used in development of the PRIOR proton
radiography facility as a part of the Facility for Anti proton and Ion Research (FAIR; Darmstadt, Ger many) project [11]. Experiments were also conducted on threedimen sional reconstruction of the internal structure of the static cylindrical sample (the simulator of a fuel ele ment for a nuclear reactor), which was a brass cylinder with a diameter of 9.2 mm and a set of longitudinal holes 0.3, 0.4, 0.5, 0.8, and 1.0 mm in diameter. The cylinder was enclosed in a stainless steel shell with a 0.3mmthick wall. The sample was mounted on the rotary manipula tor Standa 8MR151 in the vacuum chamber of the radiographic facility. The rotation accuracy was 0.6´, and the pitch was 2°. At each angle of the sample loca tion, the sample was irradiated with the proton beam and, simultaneously, the radiographic projection of the sample was recorded and processed. The internal structure of samples was restored using the algebraic reconstruction technique (ART) [12] by twodimensional proton radiography images. The external appearance of the cylindrical sample and the result of its cross cut reconstruction using the ART by 90 projections of the sample are shown in Fig. 10. The spatial resolution of the cylindrical sample image reconstructed by the sample projections is σ = 220 ± 80 μm. Dynamic Objects When investigating the evolution of fast dynamic processes, 3mmthick aluminum windows were installed in the proton beamline immediately ahead of electromagnetic lens 1 (Fig. 1) and in front of the LSO scintillator. These windows are needed for protecting the vacuum system of the facility in dynamic experi ments with the fragmentation. Accumulation of abra sion products of dynamic samples cause the ultimate vacuum in the facility to deteriorate, which results in degradation of the utmost spatial resolution of the radiographic facility (in view of the scattering in the protective windows) down to σ = 123 ± 2 μm. The detonation wave was experimentally investi gated in a cylindrical charge of pressed trinitrotoluene (TNT) with a diameter of 10 mm and a density of 1.63 g/cm3. Figure 11 presents the proton radiography images of the charge in statics and in two sequential instants of time upon detonation of explosives. For easier visualization, images in Fig. 11 are in the inverse form. Figure 12 shows the profiles of the radiographic image of the detonation wave in TNT at the axis of the charge for two sequential instants of time correspond ing to two bunches of the beam with an interval of 250 ns. The profiles were taken for the regions marked with vertical rectangles in Fig. 11.
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The stationary detonation speed was measured for the described TNT charge by the shift of the detona tion wave positions between two radiographic images. This value appeared to be V = 6.9 ± 0.2 km/s, which coincides (with the measurement accuracy) with the data in [13]. The duration of the wave front calculated by the recorded profiles shown in Fig. 12 with allow ance for the measured detonation speed appeared to be ~150 ns, which is comparable in value with the duration of the entire zone of the chemical reaction for similar highdensity TNT charges [13]. Therefore, instead of a sharp density step and its subsequent smooth decrease (i.e., the “chemical peak”), smooth increase in the TNT density up to the maximum value is observed in this region. This maximum value appears to be lower than the expected maximum amplitude of the chemical peak. Such “smearing” of the detonation wave front is caused both by the spatial resolution of radiographic images and by the displacement of the object of inves tigation (the detonation wave) during the exposure of a single radiographic image. Nevertheless, a good qualitative and quantitative agreement with the avail able experimental data is observed on the profiles in the region of the subsequent discharge [13]. The PUMA proton microscope was also used to experimentally investigate the shock compressibility and the structure of detonation waves in emulsion explosives [14]. Experiments were also carried out with the aim of investigating (using the proton radiog raphy and laser interferometry techniques) the pro cesses of slabbing destruction and jet formation upon shockwave loading of the metal plates [15]. CONCLUSIONS The PUMA proton microscope has been designed by the ITEP for carrying out proton radiography investigations of static objects with a field of vision of 20 mm and a spatial resolution of 60–115 μm at aerial densities of objects ranging from 0.46 to 17 g/cm2, respectively. A set of experiments has been performed with the aim of studying static [10] and dynamic [14] objects with an aerial density as high as 20 g/cm2. The characteristics of the spatial resolution—σ = 60 μm at a field of vision of 20 mm and a proton energy of 800 MeV—of the PUMA facility are on par with the characteristics of the proton microscope at LANSCE (Los Alamos, United States)—σ = 30 μm at a field of vision of 17 mm and σ = 65 μm at a field of vision of 44 mm for a proton energy of 800 MeV [16]. Experimental data obtained at the PUMA facility will be used in development of the PRIOR precision proton microscope for the FAIR project in Darmstadt (Germany) [11]. INSTRUMENTS AND EXPERIMENTAL TECHNIQUES
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ACKNOWLEDGMENTS This work was supported by the State Atomic Energy Corporation Rosatom (state contract nos. N.4e.45.90.10.1055 and N.4e.45.90.11.1058), Rus sian Foundation for Basic Research (grant no. 1102 01530a), and the FRRC–FAIR Russia Research Centre of Helmholtz Association (youth grant no. IK RU002). REFERENCES 1. King, N.S.P., Ables, E., Adams, K., Alrick, K.R., Amann, J.F., Balzar, S., Barnes, P.D., Crow, M.L., Cushing, S.B., Eddleman, J.C., Fife, T.T., Flores, P., Fujino, D., Gallegos, R.A., Gray, N.T., Hartouni, E.P., Hogan, G.E., Holmes, V.H., Jaramillo, S.A., Knuds son, J.N., Lobdon, R.K., Lopez, R.R., Mcdonald, D T.E., Mcclelland, J.B., Merrill, F.E., Morley, K.B., Morris, C.L., Naivar, F.J., Parker, E.L., Park, H.S., Pazuchan ics, P.D., Pillai, C., Ridel, C.M., Sarracino, J.S., Shel ley, F.E., Stacy, H.L., Takala, B.E., Thomson, R., Tucker, H.E., Yates, G.J., Ziock, H.J., and Zumbro, J.D., Nucl. Instrum. Methods Phys. Res., A, 1999, vol. 424, no. 1, p. 84. 2. Mottershead, T., Barlow, D., Blind, B., et al., Proc. 2003 Particle Accelerator Conference, Portland, Oregon, 2003, p. 702. 3. Golubev, A.A., Demidov, V.S., Demidova, E.V., Kats, M.M., Kolerov, S.B., Skachkov, V.S., Smir nov, G.N., Turtikov, V.I., Fertman, A.D., and Shar kov, B.Yu., At. Energ., 2008, vol. 104, no. 2, p. 99. 4. Golubev, A.A., Demidov, V.S., Demidova, E.V., Dudin, S.V., Kantsyrev, A.V., Kolesnikov, S.A., Min tsev, V.B., Smirnov, G.N., Turtikov, V.I., Utkin, A.V., Fortov, V.E., and Sharkov, B.Y., Tech. Phys. Lett., 2010, vol. 36, no. 2, p. 177. 5. Antipov, Yu.M., Afonin, A.G., Vasilevskii, A.V., Gusev, I.A., Demyanchuk, V.I., Zyat’kov, O.V., Ignashin, N.A., Karshev, Yu.G., Larionov, A.V., Maksi mov, A.V., Matyushin, A.A., Minchenko, A.V., Mikheev, M.S., Mirgorodskii, V.A., Peleshko, V.N., Rud’ko, V.D., Terekhov, V.I., Tyurin, N.E., Fedo tov, Yu.S., Trutnev, Yu.A., Burtsev, V.V., Volkov, A.A., Ivanin, I.A., Kartanov, S.A., Kuropatkin, Yu.P., Mikhailov, A.L., Mikhailyukov, K.L., Oreshkov, O.V., Rudnev, A.V., Spirov, G.M., Syrunin, M.A., Tatsen ko, M.V., Tkachenko, I.A., and Khramov, I.V., Instrum. Exp.Tech., 2010, vol. 53, no. 3, p. 319. 6. Kantsyrev, A.V., Bakhmutova, A.V., Golubev, A.A., Demidov, V.S., Demidova, E.V., Ladygina, E.M., Markov, N.V., Smirnov, G.N., Turtikov, V.I., Fert man, A.D., Shestov, L.M., and Khudomyasov, A.V., Instrum. Exp. Tech., 2010, vol. 53, no. 5, p. 663. 7. http://pdg.web.cern.ch/pdg/2011/reviews/rpp2011rev passageparticlesmatter.pdf 8. Makino, K. and Berz, M., Nucl. Instrum. Methods Phys. Res. A, 2005, vol. 558, no. 1, p. 346. 9. http://wwwasdoc.web.cern.ch/wwwasdoc/minuit/min main.html 10. Varentsov, D., Bogdanov, A., Demidov, V.S., Golu bev, A.A., Kantsyrev, A., Lang, P.M., Nikolaev, D.N., Vol. 57
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Translated by N. Goryacheva
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