FACULTY OF SCIENCE Increasing the Working Capabilities of the Egyptian Scanning Landmine Detectors A thesis Submitted in Partial Fulfillment of the Requirements for the Master Degree of Science in Physics, Division of Nuclear Physics To Department of Physics, Faculty of Science, University of Helwan By Mahmoud Saeed Abdelaziem Mohamed B.Sc. in Science, 2007 2013 Increasing the Working Capabilities of the Egyptian Scanning Landmine Detectors Thesis For M. Sc. Degree in Physics To Department of Physics, Faculty of Science, University of Helwan By Mahmoud Saeed Abdelaziem Mohamed B.Sc. in Science, 2007 Supervisors: 1. Prof. Dr. Rizk Abdel Moneim Rizk Department of Physics, Faculty of Science, Helwan University, Cairo, Egypt 2. Prof. Dr. Riad Mostafa Megahid Reactor Physics Department, Reactors Division, Nuclear Research Centre, Atomic Energy Authority, Cairo, Egypt 3. Dr. Ahmed Mahmoud Osman Reactor Physics Department, Reactors Division, Nuclear Research Centre, Atomic Energy Authority, Cairo, Egypt 4. Dr. Mona Mostafa Ahmed Department of Physics, Faculty of Science, Helwan University, Cairo, Egypt زﯾﺎدة ﻗﺪرات اﻟﻌﻤﻞ ﻓﻰ اﻟﻤﻨﻈﻮﻣﺔ اﻟﻤﺼﺮﯾﺔ ﻟﻠﻜﺸﻒ ﻋﻦ اﻷﻟﻐﺎم اﻷرﺿﯿﺔ رﺳـــﺎﻟﺔ ﻣﻘــــﺪﻣﺔ ﻣﻦ ﻣﺤﻤﻮد ﺳﻌﯿﺪ ﻋﺒﺪ اﻟﻌﻈﯿﻢ ﻣﺤﻤﺪ ﺑﻜﺎﻟﻮرﯾﻮس اﻟﻌﻠﻮم - ٢٠٠٧ إﻟﻰ ﻗﺴﻢ اﻟﻔﯿﺰﯾﺎء – ﻛﻠﯿﺔ اﻟﻌﻠﻮم – ﺟﺎﻣﻌﺔ ﺣﻠﻮان ﻟﻠﺤﺼﻮل ﻋﻠﻰ درﺟﺔ اﻟﻤﺎﺟﺴﺘﯿﺮ ﻓﻲ اﻟﻔﯿﺰﯾﺎء ﺗﺤﺖ إﺷﺮاف ١- أ.د/ رزق ﻋﺒﺪ اﻟﻤﻨﻌﻢ رزق أﺳﺘﺎذ اﻟﻔﯿﺰﯾﺎء اﻟﻨﻮوﯾﺔ – ﻋﻤﯿﺪ ﻛﻠﯿﺔ اﻟﻌﻠﻮم – ﺟﺎﻣﻌﺔ ﺣﻠﻮان. ٢- أ.د/ رﯾﺎض ﻣﺼﻄﻔﻲ ﻣﺠﺎھﺪ أﺳﺘﺎذ ﻓﯿﺰﯾﺎء اﻟﻨﯿﻮﺗﺮوﻧﺎت اﻟﻤﺘﻔﺮغ – ﻣﺮﻛﺰ اﻟﺒﺤﻮث اﻟﻨﻮوﯾﺔ – ھﯿﺌﺔ اﻟﻄﺎﻗﺔ اﻟﺬرﯾﺔ. ٣- د/ أﺣﻤﺪ ﻣﺤﻤﻮد ﻋﺜﻤﺎن ﻣﺪرس اﻟﻔﯿﺰﯾﺎء اﻟﻨﻮوﯾﺔ – ﻣﺮﻛﺰ اﻟﺒﺤﻮث اﻟﻨﻮوﯾﺔ – ھﯿﺌﺔ اﻟﻄﺎﻗﺔ اﻟﺬرﯾﺔ. ٤- د/ ﻣﻨﻰ ﻣﺼﻄﻔﻰ أﺣﻤﺪ ﻣﺪرس اﻟﻔﯿﺰﯾﺎء اﻟﻨﻮوﯾﺔ – ﻛﻠﯿﺔ اﻟﻌﻠﻮم – ﺟﺎﻣﻌﺔ ﺣﻠﻮان. ﻛﻠﯿﺔ اﻟﻌﻠﻮم زﯾﺎدة ﻗﺪرات اﻟﻌﻤﻞ ﻓﻰ اﻟﻤﻨﻈﻮﻣﺔ اﻟﻤﺼﺮﯾﺔ ﻟﻠﻜﺸﻒ ﻋﻦ اﻷﻟﻐﺎم اﻷرﺿﯿﺔ رﺳـــﺎﻟﺔ ﻣﻘــــﺪﻣﺔ ﻛﻤﺘﻄﻠﺐ ﺟﺰﺋﻰ ﻟﻠﺤﺼﻮل ﻋﻠﻰ درﺟﺔ اﻟﻤﺎﺟﺴﺘﯿﺮ ﻓﻰ اﻟﻔﯿﺰﯾﺎء ﺗﺨﺼﺺ اﻟﻔﯿﺰﯾﺎء اﻟﻨﻮوﯾﺔ ﻣﻦ ﻣﺤﻤﻮد ﺳﻌﯿﺪ ﻋﺒﺪ اﻟﻌﻈﯿﻢ ﻣﺤﻤﺪ ﺑﻜﺎﻟﻮرﯾﻮس اﻟﻌﻠﻮم - ٢٠٠٧ إﻟﻰ ﻗﺴﻢ اﻟﻔﯿﺰﯾﺎء – ﻛﻠﯿﺔ اﻟﻌﻠﻮم – ﺟﺎﻣﻌﺔ ﺣﻠﻮان ﻟﻠﺤﺼﻮل ﻋﻠﻰ درﺟﺔ اﻟﻤﺎﺟﺴﺘﯿﺮ ﻓﻲ اﻟﻔﯿﺰﯾﺎء 20١٣ ACKNOWLEDGMENTS I have the pleasure to express my deep gratitude to Prof. Dr. Rizk Abdel Moneim Rizk, Professor of Radiation Physics, and Dean of Faculty of Science, Helwan University, for his Kind supervision, guidance and valuable advice. I am deeply indebted to Prof. Dr. Riad Mostafa Megahid, Professor of Neutron Physics, and Former Head of Reactors Division, Nuclear Research Centre, Atomic Energy Authority, for proposing the research topics and supervising all steps of the present work. Also, I appreciate much his constructive comments, fruitful discussions and continuous support. Sincere thanks to Dr. Ahmed Mahmoud Osman, lecture of Neutron Physics, Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, for direct encouragement and help during the execution of this work. My deep thanks to Dr. Mona Mostafa Ahmed, lecture of Nuclear Physics, Department of Physics, Helwan University, for his guidance and kind supervision. I would like to thank Dr. Victor Bom, Section of Radiation Detection and Matter, Faculty of Applied Science, Delft University of Technology, Netherlands for his kind cooperation. I feel deeply thankful to all the members of Laboratories for Landmine and Illicit Materials Detection, NRC, Atomic Energy Authority, for their valuable helps during this work. Thanks are due to the Reactor Physics Department, Nuclear Research Center, Atomic Energy Authority for their continuous help during the performed measurements. LIST OF TABLES Page No. Table 2.1. Characteristics of Be (α, n) neutron sources. 10 Table 2.2. Neutron cross sections of common materials. 17 Table 2.3. Moderating properties of materials. 19 Table 2.4. Exothermic reactions used for neutron detection. 23 Table 2.5. Properties of certain inorganic scintillators. 33 Table 3.1. Elemental composition of some common explosives materials. 40 Table 3.2. Gamma-ray emission and their relative intensities 14 15 from N(nth,γ) N reaction. 55 Table 3.3. Moderating properties of various nuclei. 58 Table 4.1. Properties of the examined landmines. 86 Table 5.1. NBS count rate for various reflector shapes. 98 Table 5.2. Description of objects. 112 x LIST OF FIGURES Page No. Figure 2.1. Low-energy total neutron cross section of boron. 15 Figure 2.2. Low-energy total neutron cross section of cadmium. 15 Figure 2.3. A typical gas-filled detector: (a) the direct current produced in the circuit is measured; (b) individual pulses are detected. 20 Figure 2.4. (a) Schematic of a cylindrical proportional counter. (b) Cross-sectional view of a cylindrical proportional counter. The thin central wire acts as the anode while the outer wall acts the cathode. 21 Figure 2.5. Expected pulse height spectra from BF3 tube. (a) spectrum from a large tube in which all reaction products are fully absorbed. (b) Additional continuum due to the wall effect. 26 Figure 2.6. Expected pulse height spectrum from a ³He tube counter. 26 Figure 2.7. Photon cross sections as a function of energy for carbon and lead. 28 Figure 2.8. Photoelectric effect in a free atom. 29 Figure 2.9. Compton scattering of a photon having energy Eγ0 = hc/λ0 from a bound electron. 30 Figure 3.1. Section diagram of a PMN mine. 36 Figure 3.2. Section of an anti-tank mine showing the main charge wrapped around a red booster charge, and the secondary fuse well on the side of the mine. 37 Figure 3.3. Over-view of some common explosive structures. 39 Figure 3.4. Fully man point stick method for detection of landmines. 41 Figure 3.5. Typical Electromagnetic Induction System. 42 v Figure 3.6. Typical hand-held metal detector. 42 Figure 3.7. Basic schemes of the SQUID magnetometer electronics: (a) a flux transformer with “flux- nulling” feedback; (b) a flux transformer with 45 “current-nulling” feedback. Figure 3.8. Diagram of GPR System 47 Figure 3.9. Demining dogs. 48 Figure 3.10. High-volume sampling in a test minefield using a Nomadics battery-powered pump. 49 Figure 3.11. Principle of γ-rays backscattered imaging method. 52 Figure 3.12. Schematic view of NQR detection. 14N spin inside a landmine explosive is excited by RF wave, and then emits NQR signal 56 Figure 3.13. Schematic view of the mine detection arrangement using MNBRP. 60 Figure 3.14. FNSA Schematic 61 Figure 3.15. DT Pulsed neutron generator and its time sequence. 62 Figure 3.16. Schematic diagram of Associated Particle Technique using sealed tube neutron generator. 64 Figure 4.1. Schematic diagram for NBS detector array while scanning over a landmine. 66 Figure 4.2. Spatial distribution of backscattered thermal neutron fluxes and reconstructed 2D-images using two sources placed at 60 cm apart distance measured (a) with 16 tubes, (b) with 8 tubes. 68 Figure 4.3. Photographs of ESCALAD system arrangement (a) Side view (b) Front view. 69 Figure 4.4. Photographs of ESCALAD system arrangement after some modifications (a) Detectors fixed on arms in one bank. (b) Detectors fixed on sledges vi as two banks. (c) Detectors dragged on ground in two banks. 70 Figure 4.5. An overview of the two different types fast neutron scatterers. 71 Figure 4.6. Overview of neutron reflector. 72 Figure 4.7. A photograph of the designed reflector for ESCALAD system. 72 Figure 4.8. A photograph of the new designed reflector for ESCALAD system. 73 Figure 4.9. Experimental arrangement for (n, γ) technique. 74 Figure 4.10. Photographs of (a) boron carbide sheet. (b) semicircular shadow bar. 75 Figure 4.11. A photograph of ESCALAD system after some modifications on elemental analysis device. 75 Figure 4.12. A photograph of the rectangular like shape shadow bar. 76 Figure 4.13. A photograph of ESCALAD system with the modified bar used for elemental analysis. 76 Figure 4.14. Measured neutron spectrum from Pu-α-Be source. 77 Figure 4.15. Block diagram of electronic units used to measure NBS signals. 78 Figure 4.16. A schematic diagram shows the relation between count rate and scanning time using the old DIO board and the new DIO board. 79 Figure 4.17. Schematic diagrams show the reconstructed 2D images with different pixel size. 82 Figure 4.18. Overview of detection system: NaI(Tl) detector, pulse processing, and measuring PC. 85 Figure 4.19. Impressions from our test area and the soil vii surface. 87 Figure 5.1. Spatial distribution of backscattered thermal neutron fluxes and reconstructed 2D-images using two sources placed at 60 cm apart distance measured (a) with 16 tubes, (b) with 8 tubes. 90 Figure 5.2. Spatial distribution and reconstructed 2D-images of backscattered thermal neutrons, (a) with cylindrical scatterer, (b) with pyramidal scatterer, (c) with both scatterers. 92 Figure 5.3. Spatial distribution and reconstructed 2D-images of backscattered thermal neutrons without reflector. 93 Figure 5.4. Spatial distribution and reconstructed 2D-images of backscattered slow neutrons using a pyramid- like steel reflector. 94 Figure 5.5. Spatial distribution and reconstructed 2D-images of backscattered thermal neutron fluxes from sources placed at 60 cm apart with pyramid-like shape scatterer. 94 Figure 5.6. ATM with 2.5 kg explosive buried at zero depth using a pyramid-like shape reflector. 95 Figure 5.7. Spatial distribution and reconstructed 2D-images of backscattered thermal neutrons for a modified pyramid-like shape reflector. 96 Figure 5.8. ATM buried at zero depth using a modified pyramid-like shape reflector. 96 Figure 5.9. Spatial distribution and reconstructed 2D-images of backscattered thermal neutrons for open window pyramid-like steel reflector. 97 Figure 5.10. ATM buried at zero depth using open window pyramid-like shape reflector. 98 Figure 5.11. APM with 150 g explosive buried at zero depth. 99 Figure 5.12. APM buried at 10 cm depth. 100 viii Figure 5.13.