Contrabands detection with a low energy electron linac driven photoneutron source

Transcription

1 Contrabands detection with a low energy electron linac driven photoneutron source Yigang Yang Tsinghua University, Beijing, China yangyigang@mail.tsinghua.edu.cn

2 Outline 1. Research motivation 2. e-linac based contrabands detection 3. Summary 2 /24

3 MV X-ray images constant in MeV region I ln I 0 D N D m t m t m 3 /24

4 More information is needed In the traditional MV X-ray imaging system, mass-thickness is the only acquired information, which is not enough to indicate the existence of contrabands. Explosives, Drugs, and Special Nuclear Materials Fusion of different technologies is needed to locate and identify various contrabands from different aspects. Integrating different physics within one system can reduce the system complexity. 4 /24

5 Outline 1. Research motivation 2. e-linac based contrabands detection 1 High-Z materials detection with photons 2 High-Z materials detection with photoneutrons 3 Explosives or Drugs detection 3. Summary 5 /24

6 Dual-energy X-ray imaging / -cm 2 /g 1 Pb 0 Fe E1 E2 C Al Fe Pb R 曲线 PE Al Fe Pb -1-2 Al C B E-MeV 82 Pb 26 Fe 13 Al 6 C 5 B R = lnt H / lnt L / T H 6 /24

7 none count rate PE Al Ti Fe Cu Zn Zr Sn Gd W Pb Scattering X-ray analysis 1 Z Photoelectric absorption 7 MeV e K X-ray Z 2 W target Scattered photoelectron n 1 Z Bremsstrahlung photon Zr Lead Ti Fe Cu Al Inspected matter Lead Compton scattering Recoiled electron is scattered by Compton scattering photon coulomb field Incident photon Bremsstrahlung photon scattering photon Lead Zn 3inch Sn W LaBr (Ce) 3 Gd Pb Rayleigh scattering The interactions that cause the loss of incident photon Energy(MeV) compton scattering annhilation photon bremsstrahlung photon transmitted photon 1E-4 1E-5 14bit 120MHz ADC Pair production positron 511keV Bremsstrahlung photon 511keV annihilation CsI array for X-ray imaging Algorithm Energy(MeV) to reconstruct scattering spectra scattered electron /24

8 by analyzing the scattering X-ray spectra, Z information can be acquired R A/C Frequency R A/C Al Ti Fe Cu Zn Zr Sn Gd W Pb DU light or mediumweight metals heavy metals U R B/C R B/C R B/C Yigang.Yang, Weiqi Huang, and Yuanjing Li, "Measurement of Atomic Number by MV X-Ray Scattering Spectra Analysis," IEEE TRANSACTIONS ON NUCLEAR SCIENCE, vol. 60, p. 5, Z 8 /24

9 Outline 1. Research motivation 2. e-linac based contrabands detection 1 High-Z materials detection with photons 2 High-Z materials detection with photoneutrons 3 Explosives or Drugs detection 3. Summary 9 /24

10 Fermion and neutral particle Neutron: Neutral particle: Penetrating capability Fermion: Pauli exclusion principle Nuclei Structure gamma-rays with characteristic energies More information about contrabands can be provided by neutron related reactions. /24

11 Why e-linac driven neutron source? neutron flux isotopic 12 neutron flux n/gamma 8 neutron flux 12 7~8 ~ n/s fixed cost 12 6 n/gamma 8 fixed cost 6 ~~15 n/s 4 neutron generator Photoneutron source n/gamma fixed cost 6 life-span life-span operation cost operation cost 4 2 deployable deployable 0 neutron flux reactor ~ 17n/s/MW 12 neutron flux spallation > 17n/s/MW 12 n/gamma 8 fixed cost n/gamma 6 fixed cost life-span Low operation cost Relocatable life-span 8 operation cost life-span operation cost deployable deployable deployable 11 /24

12 Cross sections (barns) Cross sections (Barns) Cross sections (Barns) photoatomic or photonuclear reactions 2 H 9 Be 1 photoatomic reactions (PE, Rayleigh, Compton, PP) 1 photoatomic reactions (PE, Rayleigh,Compton,PP) (,n) reaction (,n) reaction 1E Energy of photons (MeV) E-4 photoatomic reactions (PE, Rayleigh, Compton, PP) Energy of photons (MeV) 238 U 1 photonuclear reactions (,n) (,fission) Energy of photons (MeV) 12 /24

13 Photons Neutrons Angular distribution of X-ray 0.034% X-ray detector array 20kg D 2 O D p n 2.6kg 9 Be photoneutron yield of e-linac 7MeV/0W : n/s MeV/20kW : n/s 9 Be 2 n 13 /24

14 7MV X-ray attenuation Photoneutron attenuation PhotoNeutron X-ray Radiography (PNXR) L=5.3 m neutron collimator inspected materials 1mm Cd Multi- Channel Scaler 1 7MeV e - pulse W 20kg D 2 O photoneutron pulse 17.8 MV X-ray pulse incident X-ray X-ray collimator 7MV X-ray attenuation 1 3 He with polyethylene or boron doped polyethylene penetrated X-ray CsI(Tl) detector photoneutron attenuation Polyethylene Aluminium Iron Copper Lead Mass thickness(g/cm 2 ) Polyethylene Melamine Urea Sugar Aluminum Iron Copper Lead 1 0 Mass thickness (g/cm 2 ) 14 /24

15 V(t) Fused X-ray image and Photoneutron image X-ray image Photoneutron image 1 In() t ln( ) I (0) n( t) t n( t) n( E ( )) () n n t V t I X () t ln( ) X ( t) t X( t) X( EX ( t)) I (0) DU Plywood Melamine Urea Sugar Paper Cloth Al Fe Cu Pb X 1 0 t (g/cm 2 ) pb 15 /24

16 Neutron count rate ratio (sample / air) Beta-delayed neutrons detection W Pb DU Existence of fissionable material is confirmed 1 Background line delayed neutrons of U Time delay after each X-ray pulse ( s) Group T1/2 (s) 55.72± ± ± ± ± ±0.025 W. H. Yigang Yang, Yuanjing Li, "The integration of Photon and Neutron method for contrabands detection with a 7MeV Linac," 2011 IEEE Nuclear Science Symposium Conference Record, p. 3, /24

17 1.0 Ag 1.0 Ho 1.0 Er transmission transmission * *Concentration (barns*ev) transmission Isotopes identification through photoneutron resonant attenuation Sb 5.19 ev 1 0 E n (ev) W ev 3.91 ev 1 0 E n (ev) Ta 0.46 ev 0.58 ev 5.99 ev 1 0 E n (ev) Nd 6.24 ev 1 0 E n (ev) Tb 7.64 ev 4.15 ev ev 1 0 E n (ev) ev.34 ev E n (ev) high-z simulants 235 U 238 U 186 W ev eV 3.34 ev 00 9 Ag 181 Ta 165 Ho 167 Er 159 Tb 181 Ta 165 Ho Er 159 Tb 182 W 121 Sb E n (ev) E n (ev) Er 145 Nd 183 W 1 17 /24

18 Steps for locating and identifying SNMs step1: <2 minutes step2: seconds to 1 minute step3: 19 minutes or more Inspected by X-ray and photoneutron penetration Vt () Heavy metal? Yes Beta-delayed neutron analysis No clearance & go-ahead Neutorn _ count > threshold Yes Neutron resonance analysis No clearance & go-ahead 235 U _ abundance >93% 235 U Yes SNM No Depleted or low enriched Uranium Yigang Yang*,Zhi Zhang,Huaibi Chen,Yulan Li,Yuanjing Li. Identification of high-z materials with photoneutrons driven by a low-energy electron linear accelerator. IEEE Transactions on Nuclear Science (accepted on Dec. 12, 2016, in press DOI: 19/TNS ) 18 /24

19 Outline 1. Research motivation 2. e-linac based contrabands detection 1 High-Z materials detection with photons 2 High-Z materials detection with photoneutrons 3 Explosives or Drugs detection 3. Summary 19 /24

20 (n, γ) analysis for explosives or drugs 1 N 0 v spectrum No Y. Yigang, L. Yuanjing, W. Haidong, L. Tiezhu, and W. Bin, Explosives detection using photoneutrons produced by X- 20 /24 rays, Nuclear Inst. and Methods in Physics Research, A, vol. 579 (2007), pp

21 Fusion of X-ray image and elemental concentration distribution H N Cl Fe Yigang Yang, Jianbo Yang and Yuanjing Li, "Fusion of X-ray Imaging and Photoneutron Induced Gamma Analysis for Contrabands Detection," IEEE TRANSACTIONS ON NUCLEAR SCIENCE, vol. 60, p. 6, /24

22 Drugs or explosives detection system 22 /24

23 3.Summary An e-linac can produce both X-rays and photoneutrons. Properties of the photoneutron source: 1 High neutron yield 2 Long life-span & Robustness 3 Relocatable and suitable for the field use 4 Pulsed mode, enabling the energy selective methods The philosophy of one-source, two-radiation, multi-physics can be supported by the e-linac driven photoneutron source to enhance the contrabands detection capability. 23 /24

24 one-source, two-radiation, multi-physics for the contrabands detection Atomic number analysis by analyzing the scattered MV X-ray spectrum Photoneutron production Photoneutron resonant analysis Photoneutron and X-ray radiography Photoneutroninduced gamma-ray analysis Beta-delayed neutron measurement 970 s electron pulse n ~ 2000 s ~ 6250 s 4250 s electron pulse n ns 5 s 30 s En 200eV En 00 s 6eV 2000 s 6250 s time MV X-ray imaging for the mass-thickness measurement or dual energy inspection 24 /24

25 Thanks for your attention & Questions please 25 /24

26 26 /24

27 1. Research motivation In the traditional MV X-ray imaging system, mass-thickness is the only acquired information, which is not enough to indicate the existence of contrabands. Explosives, Drugs, and Special Nuclear Materials Fusion of different technologies is needed to locate and identify various contrabands from different aspects. Integrating different physics within one system can reduce the system complexity. 27 /24

28 Frequency Al Ti Fe Cu Zn Zr Sn Gd W Pb DU R B/C Organic materials 28 /24