Nuclear Track Detectors for Relativistic Nuclear Fragmentation Studies: Comparison with Other Competitive Techniques

Mukhtar Ahmed Rana, Gul Sher, Shahid Manzoor, Fariha Malik, Kanwal Naz

Informatics Complex, H-8, Islamabad, Pakistan.
Isotope Applications Division, PINSTECH, Islamabad, Pakistan.
Materials Division, Directorate of Technology, PINSTECH, Islamabad, Pakistan.
Physics Department, COMSATS Institute of Information Technology (CIIT), Islamabad Campus, Islamabad, Pakistan.
The Pakistan Strategist Company, An SPD Project, PINSTECH-Admin Blk., Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad, Pakistan;Physics Department, University of Balauchistan, Quetta, Pakistan;National Tokamak Plasma and Fusion Project, NILOP, PAEC, Islamabad, Pakistan.

DOI: 10.4236/mi.2013.23008                

Abstract

The potential of the high resolution nuclear track detector (NTD) CR-39 is examined carefully for the measurement of relativistic nuclear projectile fragmentation cross sections and studies of related processes using the experience of many years of such measurements. The charge resolution and the charge resolving power of CR-39 detectors for the measurements of 158 A GeV ²⁰⁷Pb projectiles and their fragments are presented. Exposures of target-detector stacks, the chemical etching procedure and the nuclear track measurements are described in detail discussing precautions and possible errors. The procedures discussed are also valid for other NTDs. A comparison with electronic active detectors is also made considering important detection and measurement aspects. An experimental design proposing the co-use of NTDs with in-use active detectors is described.

Keywords

Nuclear Track Detection Methodology (NTDM); CR-39 Detectors; Nuclear Fragmentation; Charge Resolution; Fragmentation Cross Sections

1. Introduction

Fragmentation properties of shielding materials can affect protection of astronauts seriously. Radiations have also an adverse effect on microelectronic devices employed in the control systems of high altitude commercial aviation aircrafts and spacecrafts, leading to the failure of such devices [1]. Nuclear fragmentation cross sections are crucial to issues of radiation transport through shielding materials and resulting shielding effect [2]. Nuclear fragmentation cross sections also give information about collision dynamics of high energy heavy nuclei like lead and uranium. Various techniques [3-8] have been employed for studies of nuclear fragmentation and other reactions, including solid state nuclear track detector (NTD) [9-18]. Here, we discuss experimental methods and related problems for the measurement of fragmentation cross sections using NTDs. The present paper is based on the results from several investigations on the methodology of nuclear tracks [19-21] and the use of NTDs in nuclear fragmentation studies [22-25]. Present paper addresses two issues: 1) Concise description of experiments to detect fragments of exotic nuclear reaction with CR-39 and other nuclear track detectors and 2) evaluation of experimental methods for the measurement of relativistic charged particles by passive and active detectors. The study of such processes is important for fundamental physics reasons and technical applications in fusion plasma, dosimetry in space and heavy ion therapy. Due to these reasons, the present study is interesting for several scientists in nuclear physics and their application.

2. High Sensitivity High Resolution Detector CR-39

An NTD is a solid material (normally plastic, glass or a crystal), when exposed to a single charged radiation, a damaged trail of diameter 2 - 10 nm is produced which, through chemical etching, can be amplified to microscopically observable conical shapes. The main advantages over other radiation detectors are the detailed information available on individual particles, the persistence of the tracks allowing measurements to be made over long periods of time, and the simple, cheap and robust construction of the detector. A material commonly known and used as an NTD is CR-39. Its chemical name is polyallyl diglycol carbonate (PADC). It is a transparent and rigid plastic material with the chemical formula C₁₂H₁₈O₇. Etching is usually performed in solutions of caustic alkalis such as sodium or potassium hydroxide at temperatures of 60˚C ± 30˚C from few minutes to several hours. CR-39 is the most sensitive and the highest resolution NTD. It is sensitive to a wide range of charges down to Z = 1-6e (depending on the Z/β of the incident particle. Its charge resolution of 0.05e for precisely designed exposure and etching experiments. CR-39 was used to search for exotic particles, like Magnetic Monopoles and Strange Quark Matter (SQM) to study cosmic ray composition and for environmental studies [26].

3. Experimental Methodology

3.1. Target-Detector Assemblies and Exposures

Nuclear track detectors can be employed for the measurement of fragmentation cross sections of relativistic projectiles using appropriate target-stack designs. We have employed CR-39 detectors (prepared by Intercast Europe Company of Parma, Italy) for fragmentation studies of relativistic projectiles on various targets. The method of these experiments is the measurement of the beam incident on the target and after the target where are present the survived beam and the fragments or seconddary particles produced in the interaction of the incident beam with the target.

The design of target-detector assemblies and exposure geometry are shown in Figure 1. Several such stacks of CR-39 detectors and targets were exposed to 158 A GeV ²⁰⁷Pb beams at the CERN SPS facility. The target thicknesses were chosen in such a way that multiple interactions were negligible, but still appropriate to produce sufficient fragments. The CR-39 detector plates were 11.5 × 11.5 cm² in size and 600 μm in thickness. CR-39 detectors upstream of the targets were used for the determination of the total number of incident Pb ions. The density of lead beam ions was around 1500 ions/cm². The beam then passed through a target of thickness typically half of the mean free path of the Pb ions in the

Figure 1. Schematic showing (a) Stack of NTDs and (b) exposure geometry.

given target. CR-39 foils downstream of the target recorded both the survived Pb ions and their fragments produced in targets. NTD based experiments are very simple compared to those which employ multi wire proportional chambers (MWPCs), ionization chambers (ICs) and Cherenkov detectors (CDs) [27,28]. The later experiments necessitate an online data acquisition whereas NTDs provide the possibility of offline data acquisition and are attractive for research groups which do not have direct access to high energy accelerator facilities.

3.2. Chemical Etching

Chemical etching is an essential step for NTD experiments. Etching amplifies the nanometer diameter particle trails in NTDs to microscopic dimensions appropriate for observations with optical microscopes. Nuclear track etching involves a number of factors without precisely quantized control. Most important factors are concentrations of active etching species or molecules in etchant, temperature control and stability. The variation in etching behavior of the detector material causes uncertainty in experimental etching results. The variation in the etching temperatures was not more than ±1˚C. A standardized process was used during etching of exposed CR-39 detectors. An efficient and stable level of stirring was maintained. Concentration of etchant was kept effectively constant under specific etching conditions by minimizing the water evaporation from the etching solution. Exposed CR-39 detectors were etched in 4N KOH water solution at a temperature of 45˚C for 72 h. An average thickness of about 8 μm was removed from both sides of the detector with an average bulk etch rate of 0.112 ± 0.021 μm/h. The refractive index of the CR-39 was experimentally determined as 1.561 which was later used for the determination of the total height of the etched cones.

3.3. Track Measurements

Measurement of track parameters is an extremely slow process if it is done manually. All the track measurements at the PINSTECH laboratory were done manually. Manual measurements are very slow compared with automatic scanning systems, but provide visual insights of track forming particles. Discrimination between real events and background or erroneous events is more trustworthy in manual measurements compared to the discrimination made by an automatic nuclear track scanning. The measurement of cone heights of tracks in three CR-39 foils for the case of each target used, one set of foils for each target used, one set of foils before every target and two after, were measured with an optical microscope manually (more than 6000 etched cones were measured in each foil). It was observed that the cone length increased with increasing ion charges. Measurements of nuclear fragmentation were made with observations of change in cone heights. Zeiss optical microscope with a magnification of 40× was used for these measurements. Cone heights of Pb projectiles and fragments were measured by the top view using the depth measuring system coupled with the microscope. Difference of readings on depth measuring instrument, one when track diameter at the detector surface is focused and other when endpoint of etchable range is focused in the microscope, gives the cone height of a track. Track length measurement resolution or least count of the optical microscope used was ±0.5 μm.

4. Fragmentation Results

4.1. Detector Observations

Figure 2 shows the etched cone distribution for tracks of lead projectiles (a), and fragments produced in the interaction of Pb ions on stationary CR-39 (b), Al (c) and Cu (d) targets, observed with CR-39 detector. In each plot, each peak can be designated with a charge Z as most of the projectile energy is deposited in a solid (CR-39 here) through Coulomb interaction. In all the three cases of Pb projectile fragmentation in different targets (b, c and d), fragments down to Z value of 63 are observable in CR-39. Counts in each peak are a measure of production cross section of the corresponding fragment. So, each peak represents production yield of fragments with a specific Z. Well-defined and separated peaks mean precise measurements. It is worth mentioning that detector, beam and etching conditions were same for all plots, but range of etched cone height is different for the case of Al (C) from other three cases. Major differences are difference in brands of KOH used and different chemical etching equipment. Major differences in etching equipment include difference in size and different magnitudes of stirring during etching.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	M. Zmeck, J. Phang, A. Bettiol, T. Osipowicz, F. Watt, L. Balk, F.-J. Niedernostheide, H.-J. Schulze, E. Falck and R. Barthelmess, “Analysis of High-Power Devices Using Proton Beam Induced Charge Microscopy,” Microelectronics Reliability, Vol. 41, No. 9-10, 2001, pp. 1519-1524. doi:10.1016/S0026-2714(01)00159-7
[2]	J. W. Wilson, J. L. Shinn, L. W. Townsend, R. K. Tripathi, F. F. Badavi and S. Y. Chun, “NUCFRG2: A Semiempirical Nuclear Fragmentation Model,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 94, No. 1-2, 1994, pp. 95-102. doi:10.1016/0168-583X(94)95662-6
[3]	C. Scheidenberger, et al., “Charge-Changing Interactions of Ultrarelativistic Pb Nuclei,” Physical Review C, Vol. 70, No. 1, 2004, Article ID: 014902. doi:10.1103/PhysRevC.70.014902
[4]	L. Y. Geer, J. Klarmann, B. S. Nilsen, C. J. Waddington, W. R. Binns, J. R. Cummings and T. L. Garrard, “Charge-Changing Fragmentation of 10.6 GeV/Nucleon 197Au Nuclei,” Physical Review C, Vol. 52, No. 1, 1995, pp. 334-335. doi:10.1103/PhysRevC.52.334
[5]	W. R. Weber, J. C. Kish and D. A. Schrier, “Total Charge and Mass Changing Cross Sections of relativistic nuclei in Hydrogen, Helium, and Carbon Targets,” Physical Review C, Vol. 41, No. 2, 1990, pp. 520-532. doi:10.1103/PhysRevC.41.520
[6]	W. R. Weber, J. C. Kish and D. A. Schrier, “Individual Charge Changing Fragmentation Cross Sections of Relativistic Nuclei in Hydrogen, Helium, and Carbon Targets,” Physical Review C, Vol. 41, No. 2, 1990, pp. 533-546. doi:10.1103/PhysRevC.41.533
[7]	C. Zeitlin, S. Guetersloh, L. Heilbronn, J. Miller, A. Fukumura, Y. Iwata, T. Murakami, L. Sihver and D. Mancusi, “Fragmentation Cross Sections of Medium-Energy 35Cl, 40Ar, and 48Ti Beams on Elemental Targets,” Physical Review C, Vol. 77, No. 3, 2008, Article ID: 034605. doi:10.1103/PhysRevC.77.034605
[8]	K.-H. Schmidt , A. Kelic and M. V. Ricciardi, “Experimental Evidence for the Separability of Compound-Nucleus and Fragment Properties in Fission,” Europhysics Letters, Vol. 83, No. 3, 2008, Article ID: 32001. doi:10.1209/0295-5075/83/32001?
[9]	G. Giacomelli, et al., “Extended Calibration of a CR39 Nuclear Track Detector with 158 A GeV. 207Pb Ions,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 411, No. 1, 1998, pp. 41-45. doi:10.1016/S0168-9002(98)00270-8
[10]	S. Cecchini, et al., “Fragmentation Cross Sections of Fe26+, Si14+ and C6+ Ions of 0.3 -10 A GeV on Polyethylene, CR39 and Aluminum Targets,” Nuclear Physics A, Vol. 807, No. 3-4, 2008, pp. 206-213. doi:10.1016/j.nuclphysa.2008.03.017
[11]	S. Manzoor, et al., “Nuclear Track Detectors for Environmental Studies and Radiation Monitoring,” Nuclear Physics B—Proceedings Supplements, Vol. 172, 2007, pp. 92-96. doi:10.1016/j.nuclphysbps.2007.07.017
[12]	S. Balestra, et al., “Bulk Etch Rate Measurements and Calibrations of Plastic Nuclear Track Detectors,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 254, No. 2, 2007, pp. 254-258. doi:10.1016/j.nimb.2006.11.056
[13]	W. Heinrich, et al., “High Energy Heavy Ion Interactions Studied with SSNTDs,” Radiation Measurements, Vol. 25, No. 1-4, 1995, pp. 203-218. doi:10.1016/1350-4487(95)00075-P
[14]	S. Kodaira, N. Yasuda, H. Kawashima, M. Kurano, N. Hasebe, T. Doke, S. Ota, T. Tsuruta, H. Hasegawa, S. Sakai, T. Nishi and K. Ogura, “Characteristics of the Copolymerized CR-39/DAP Track Detector for the Observation of Ultra Heavy Nuclei In Galactic Cosmic Rays,” Radiation Measurements, Vol. 44, No. 9-10, 2009, pp. 775-778. doi:10.1016/j.radmeas.2009.10.050
[15]	P. B. Price and Y. D. He, “Behavior of Nuclear Projectile Fragments Produced in Collisions of 14.5 A GeV 28Si with Pb and Cu Targets,” Physical Review C, Vol. 43, No. 2, 1991, pp. 835-848. doi:10.1103/PhysRevC.43.835
[16]	M. Giacomelli, L. Sihver, J. Skvarc, N. Yasuda and R. Ilic, “Projectilelike Fragment Emission Angles in Fragmentation Reactions of Light Heavy Ionsin the Energy Region <200 MeV/Nucleon: Modeling and Simulations,” Physical Review C, Vol. 69, No. 6, 2004, Article ID: 064601. doi:10.1103/PhysRevC.69.064601?
[17]	A. N. Golovchenko, J. Skvarc, R. Ilic, L. Sihver, V. P. Bamblevski, S. P. Tretyakova, D. Schardt, R. K. Tripathi, J. W. Wilson and R. Bimbot, “Fragmentation of 200 and 244 MeV/u Carbon Beams in Thick Tissue-Like Absorbers,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 159, No. 4, 1999, pp. 233-240. doi:10.1016/S0168-583X(99)00546-7?
[18]	A. N. Golovchenko, L. Sihver, S. Ota, J. Skvarc, N. Yasuda, S. Kodaira, G. N. Timoshenko and M. Giacomelli, “Fragmentation of 370 MeV/n 20Ne and 470 MeV/n 24Mg in Light Targets,” Radiation Measurements, Vol. 454, No. 7, 2010, pp. 856-860. doi:10.1016/j.radmeas.2010.03.006?
[19]	M. A. Rana, “Nuclear Tracks: Defect Structure of Latent Tracks, Chemical Etching and Future Directions,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 268, No. 2, 2010, pp. 165-171. doi:10.1016/j.nimb.2009.10.171
[20]	M. A. Rana, “On Problems in Trustworthy Predictions of Etched Track Parameters,” Radiation Measurements, Vol. 43, No. 9-10, 2008, pp. 1546-1549. doi:10.1016/j.radmeas.2008.09.002
[21]	M. A. Rana, E. U. Khan, M. I. Shahzad, S. Manzoor, G. Sher and I. E. Qureshi, “Characteristics of Antiproton Tracks in CR-39,” Radiation Measurements, Vol. 42, No. 2, 2007, pp. 125-129. doi:10.1016/j.radmeas.2006.12.002
[22]	S. Manzoor, I. E. Qureshi, M. A. Rana, M. I. Shahzad, G. Sher, M. Sajid, H. A. Khan, G. Giacomelli, M. Giorgini, G. Mandrioli, L. Patrizii, V. Popa, P. Serra and V. Togo, “Charge Identification in CR-39 Nuclear Track Detector Using Relativistic Lead Ion Fragmentation,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 453, No. 3, 2000, pp. 525-529. doi:10.1016/S0168-9002(00)00470-8
[23]	I. E. Qureshi, M. I. Shahzad, M. T. Javed, S. Manzoor, G. Sher, F. Aleem and H. A. Khan, “Study of Projectile Fragmentation in the Reaction (158 A GeV) Pb + Pb Using CR-39,” Radiation Measurements, Vol. 40, No. 2-6, 2005, pp. 437-441. doi:10.1016/j.radmeas.2004.11.013
[24]	M. A. Rana and S. Manzoor, “Examining the Fragmentation of 158 A GeV Lead Ions on Copper Target: Charge-Changing Cross Sections,” Radiation Measurements, Vol. 43, No. 8, 2008, pp. 1383-1389. doi:10.1016/j.radmeas.2008.05.004
[25]	G. Sher, M. I. Shahzad and M. Hussain, “Fragmentation of (158 A GeV) Pb Ions with Bi Target,” Radiation Measurements, Vol. 42, No. 10, 2007, pp. 1692-1695. doi:10.1016/j.radmeas.2007.09.006
[26]	M. Giorgini, “The Nuclear Track Detector CR39: Results from Different Experiments,” Nuclear Physics B—Proceedings Supplements, Vol. 197, No. 1, 2009, pp. 66-69. doi:10.1016/j.nuclphysbps.2009.10.036
[27]	C. Leroy, “Review of Radiation Detectors,” AIP Conference Proceedings, Vol. 1204, 2009, p. 49.
[28]	C. Leroy and P. G. Rancoita, “Principles of Radiation Interaction in Matter and Detection,” World Scientific, Singapore, 2004.
[29]	E. V. Benton and W. G. Nix, “The Restricted Energy Loss Criterion for Registration of Charged Particles in Plastics,” Nuclear Instruments and Methods, Vol. 67, No. 2, 1969, pp. 343-347. doi:10.1016/0029-554X(69)90471-6
[30]	S. Balestra, et al., “Bulk Etch Rate Measurements and Calibrations of Plastic Nuclear Track Detectors,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 254, No. 2, 2007, pp. 254-258. doi:10.1016/j.nimb.2006.11.056
[31]	N. U. Khattak, M. Akram, M. A. Khan and H. A. Khan, “Emplacement Time of the Loe-Shilman Carbonatite from NW Pakistan: Constraints from Fission-Track Dating,” Radiation Measurements, Vol. 43, Suppl. 1, 2008, pp. S313-S318. doi:10.1016/j.radmeas.2008.03.038
[32]	B. Jurado, C. Schmitt, K.-H. Schmidt, J. Benlliure, T. Enqvist, A. R. Junghans, A. Kelic and F. Rejmund, “Transient Effects in Fission from New Experimental Signatures,” Physical Review Letters, Vol. 93, No. 7, 2004, Article ID: 072501. doi:10.1103/PhysRevLett.93.072501
[33]	T. Kunert and R. Schmidt, “Excitation and Fragmentation Mechanisms in Ion-Fullerene Collisions,” Physical Review Letters, Vol. 86, No. 23, 2001, pp. 5258-5261. doi:10.1103/PhysRevLett.86.5258
[34]	A. D. Boozer, “Simulating a One-Dimensional Plasma,” American Journal of Physics, Vol. 78, No. 6, 2010, pp. 580-584. doi:10.1119/1.3290442
[35]	T. Siemiarczuk and P. Zielinski, “Fragmentation of Xenon Nuclei Induced by 9 GeV/c Negative Pions and the Possibility of Shock Wave Propagation in Nuclei,” Physical Review C, Vol. 13, No. 6, 1976, pp. 2439-2443. doi:10.1103/PhysRevC.13.2439
[36]	M. A. Rana, S. Manzoor and G. Sher, “Charge and Mass Changing Cross-Sections of 158 A GeV Pb Projectiles on Al, Cu, Bi, and Pb Targets: Fragmentation Processes,” International Journal of Modern Physics E, Vol. 19, No. 10, 2010, p. E19. doi:10.1142/S0218301310016466
[37]	H. Thomas, G. E. Morfill, V. Demmel, J. Goree, B. Feuerbacher and D. M?hlmann, “Plasma Crystal: Coulomb Crystallization in a Dusty Plasma,” Physical Review Letters, Vol. 73, 1994, pp. 652-656.
[38]	C.-R. Du, K. R. Sütterlin, A. V. Ivlev, H. M. Thomas and G. E. Morfill, “Model Experiment for Studying Lane Formation in Binary Complex Plasmas,” Europhysics Letters, Vol. 99, No. 4, 2012, Article ID: 45001.
[39]	W. Masood, H. Rizvi, H. Hasnain and Q. Haque, “Rotation Induced Nonlinear Dispersive Dust Drift Waves Can be the Progenitors of Spokes,” Physics of Plasmas, Vol. 19, No. 3, 2012, pp. 32112-32118. doi:10.1063/1.3688077
[40]	M. A. Rana, “How to Achieve Precision and Reliability in Experiments Using Nuclear Track Detection Technique?” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 592, No. 3, 2008, pp. 354-360. doi:10.1016/j.nima.2008.04.025
[41]	M. Ambrosio, et al., “The MACRO Detector at Gran Sasso,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 486, No. 3, 2002, pp. 663-707. doi:10.1016/S0168-9002(01)02169-6
[42]	M. Ambrosio, et al., “Final Results of Magnetic Monopole Searches with the MACRO Experiment,” The European Physical Journal C: Particles and Fields, Vol. 25, No. 4, 2002, pp. 511-522. doi:10.1140/epjc/s2002-01046-9
[43]	M. Ambrosio, et al., “Magnetic Monopole Search with the MACRO Detector at Gran Sasso,” Physics Letters B, Vol. 406, No. 3, 1997, pp. 249-255. doi:10.1016/S0370-2693(97)00684-9
[44]	P. B. Price, L. M. Cook and A. Markert, “Phosphate Glasses for Identification of Heavy Ions,” Letters to Nature, Vol. 325, 1987, pp. 137-138. doi:10.1038/325137a0
[45]	D. Zhou, E. Semones, D. O’Sullivan, N. Zapp, M. Weyland, G. Reitz, T. Berger and E. R. Benton, “Radiation Measured for MATROSHKA-1 Experiment with Passive Dosimeters,” Acta Astronautica, Vol. 66, No. 1-2, 2010, pp. 301-308. doi:10.1016/j.actaastro.2009.06.014
[46]	E. R. Benton, E. V. Benton, A. L. Frank and M. F. Moyers, “Characterization of the Radiation Shielding Properties of US and Russian EVA Suits Using Passive Detectors,” Radiation Measurements, Vol. 41, No. 9-10, 2006, pp. 1191-1201. doi:10.1016/j.radmeas.2006.04.030
[47]	E. R. Benton and E. V. Benton, “Space Radiation Dosimetry in Low-Earth Orbit and Beyond,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 184, No. 1-2, 2001, pp. 255-294. doi:10.1016/S0168-583X(01)00748-0
[48]	J. L. Pinfold, “Searching for the Magnetic Monopole and Other Highly Ionizing Particles at Accelerators Using Nuclear Track Detectors,” Radiation Measurements, Vol. 44, No. 9-10, 2009, pp. 834-839. doi:10.1016/j.radmeas.2009.10.062
[49]	G. Sher, M. Rana and M. Shahzad, “Lead Projectile Fragmentation on Aluminum Target: Improved Experimental Results,” World Journal of Nuclear Science and Technology, Vol. 1, 2011, pp. 13-19. doi:10.4236/wjnst.2011.11003
[50]	S. Eman, S. Nageeb and A. El-Sersy, “U and Th Determination in Natural Samples Using CR-39 and LR-115 Track Detectors,” World Journal of Nuclear Science and Technology, Vol. 2, 2012, pp. 36-40. doi:10.4236/wjnst.2012.21006
[51]	M. Abd-Elzaher, M. Badawi, A. El-Khatib and A. Thabet, “Determination of Full Energy Peak Efficiency of NaI(Tl) Detector Depending on Efficiency Transfer Principle for Conversion Form Experimental Values,” World Journal of Nuclear Science and Technology, Vol. 2, 2012, pp. 65-72. doi:10.4236/wjnst.2012.23011
[52]	R. Pleskac, et al, “The FIRST Experiment at GSI,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 678, 2012, pp. 130-138. doi:10.1016/j.nima.2012.02.020
[53]	B. Braunn, et al., “Nuclear Reaction Measurements of 95 MeV/u 12C Interactions on PMMA for Hadrontherapy,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 269, No. 22, 2011, pp. 2676-2684. doi:10.1016/j.nimb.2011.08.010