Development status of non-destructive assay of nuclear material by using laser Compton scattered gamma-rays

Transcription

1 Development status of non-destructive assay of nuclear material by using laser Compton scattered gamma-rays Ryoichi Hajima Japan Atomic Energy Agency IZEST Tokyo 2013 Nov. 18, 2013

2 Collaborators Quantum Beam Science Directorate, JAEA Gamma-ray NDA Group T. Hayakawa, T. Shizuma, C. Angell, M. Sawamura, R. Nagai, N. Nishimori, S. Matsuba Advanced Laser Dev. Group M. Mori, A. Kosuge, H. Okada, K. Nagashima Integrated Support Center for Nuclear Nonproliferation and Nuclear Security, JAEA M. Seya KEK H. Kawata, Y. Kobayashi, J. Urakawa and the cerl team Kyoto Univ. H. Ohgaki Osaka Univ. M. Fujiwara 2

3 Laser Compton Scattered gamma-ray at KEK-ATF -ray Supercavity Laser Electron bunch Courtesy of J. Urakawa 3

4 Nuclear Resonance Fluorescence (NRF) Energy [kev] Nuclear Resonance Fluorescence (NRF) Tunable Flux of gamma-rays / / Am Absorption Emission Absorption Emission 237 Np 239 Pu U U fingerprint W A N T E D MeV for U-238 NRF signal U MeV E E/E < 1% detector target E -ray beam Photon Energy (MeV) R. Hajima et al., J. Nucl. Sci. Tech. 45, (2008) Photon energy (MeV) 4

5 Experimental Demonstration nondestructive detection of isotope Pb block shielded by 15mm-thick iron box 5512 kev Pb-208 Position and shape of the Pb block were clearly identified. ~ 10 AIST N. Kikuzawa et al., Applied Physics Express 2, (2009). 5

6 Flux and Brightness of LCS sources Flux : photons/s F total 16 3 N e N electrons laser photons L f r w electron classical radius collision spot size collision frequency Spectral Brightness: photons/s/mm 2 /mrad 2 /0.1%BW B F total 2 2 n 0.1% for the higher brightness higher collision density higher repetition rate smaller emittance 6

7 Analytical evaluation of on-axis brightness peak brilliance (ph/mm 2 /mrad 2 /s/0.1%bw) 1e+18 n =1.0mm-mrad 8e+17 6e+17 4e+17 2e gamma-ray energy (kev) peak brilliance (ph/mm 2 /mrad 2 /s/0.1%bw) 5e+19 4e+19 n =0.1mm-mrad 3e+19 2e+19 1e gamma-ray energy (kev) calculation by using a formula in [1]. [1] F.V. Hartemann et at. Phys. Rev. ST AB 8, (2005). 7

8 Concept of a high-flux -ray source by using ERL High-repetition, high-density collision of e-beam and laser. Small emittance e-beam laser enhancement cavity -ray Supercavity Laser Electron bunch Energy Recovery Linac laser photons are recycled high-flux -ray Electron beam = 350 MeV, 13 ma Laser intracavity = 700 kw LCS ~2MeV, 1x10 13 ph/s 0.1 ph/ev/s 10^7 ph/ev/s AIST ERL electron energy is recycled Acceleration Deceleration R. Hajima et al., NIM-A608 (2009) 8

9 Measurement of Pu in spent fuels For detection of diversion of fuel pins from a spent nuclear fuel Spent Fuel Assembly ~ 25 m Next Generation ERL (350 MeV) Gamma-ray detectors Lase Enhanced Cavity LCS Gamma-rays with Energy 2-3 MeV This system could be used for precise quantitative measurements of all of Pu/U isotopes in each fuel rods using 2-3 MeV gamma-rays. 9

10 LCS -ray for Fukushima Measurement of Pu in the melted fuel necessary for nuclear nonproliferation! removal of debris from the core ~2021 Slab Debris Small Rock-Debris Debris of Melted Fuel Energy-Recovery Linac (350 MeV) -ray detectors -ray generation -ray beam pipe 10

11 Scattering Method Slab Debris Water-filled Case Scan NRF gamma-ray from Pu-239 LCS Gamma-rays Scan Detector 3 Detector U kev Detector 1 Detector 2 Measurements of position of depth 60 Count/ch Energy (kev) 11

12 Witness Plate = Resonance Transmission Absorption is proportional to amount of Pu-239 NRF rate at witness plate is proportional to amount of flux at Pu-239 energy. Energy spectra of LCS -ray Flux Measured Pu-239 NRF Gamma-rays Flux Pu-239 NRF energy Energy NRF Gamma-rays Energy Incident LCS gamma-rays Slab debris containing Pu-239 Witness plate with Pu-239 Ge detector Estimated Pu-239 NRF Gamma-rays with incident LCS Gamma-ray 12

13 Integral Resonance Transmission Sodium Iodide (scintillator) γ ray detectors Witness plate ( 239 Pu) Sample (a fuel assembly in this case) Gamma-ray beam Wall and/or beam collimator Measure the reduction in NRF scattering from all states Integrate entire signal in 238 U NRF region of beam energy: 2-3x Increase Enables use of higher efficiency scintillator detectors. C. Angell et al., Proc. INMM (2012) Figure from Hammond et al. Phys. Rev. C (2012) 13

14 Performance of the melted fuel measurement Time s (8 hrs) Flux ph/s Aerial density of assembly 64 g/cm 2 (assuming 99% U) Pu mass fraction 1% Thickness of witness plate 1 cm (Pu 239 metal) Beam Energy 2.4 MeV 3.5% 239 Pu Mass Uncertainty 3.0% 2.5% 2.0% 1.5% 1.0% 0.5% Statistical error = 0.13% 0.0% Single Resonance Integral Resonance Photofission Single resonance Integral resonance Photofission C. Angell et al., Proc. INMM (2012) 239 Pu Assay: 1% in about 8 mins! 14

15 R&D Program Funded from MEXT ( ) Demo-Experiment at the Compact ERL Installation of a LCS chamber Generation of LCS gamma-rays Demo-Experiment of NRF measurement Building superconducting accelerator (9-cell x 2 cavity) electron gun LCS experimental rooms LCS gamma-rays LCS chamber 1-loop Electron beam = 35 MeV, 10 ma LCS flux ~ 1x10 11 ph/s 15

16 Critical Components for LCS -ray Electron Gun Generation of an electron beam with small emittance and large current Superconducting accelerator Laser & enhancement cavity Acceleration of an e-beam and energy recovery e-beam laser Store laser pulses coherently 16

17 500-kV photocathode DC gun for ERL injector guard rings R. Nagai et al. Rev. Sci. Instr. 81, (2010) field emission support rod ceramic applied Voltage [-kv] high-voltage of 500 kv had been applied for 8 hours without any discharge time [hour] 50 0 current [ A] 17

18 Goals of the Compact ERL The Compact ERL Demonstrate reliable operations of our R&D products (guns, SRF,...) Demonstrate the generation and recirculation of ultra-low emittance beams Parameters of the Compact ERL Parameters Beam energy (upgradability) Injection energy Average current Acc. gradient (main linac) Normalized emittance Bunch length (rms) RF frequency 35 MeV 125 MeV (single loop) 245 MeV (double loops) 5 MeV 10 ma (100 ma in future) 15 MV/m 0.1 mm mrad (7.7 pc) 1 mm mrad (77 pc) 1-3 ps (usual) ~ 100 fs (with B.C.) 1.3 GHz 18

19 Major Components for the cerl DC photo Gun (500-kV, 10mA) Injector SRF (2-cell x 3 cavity) Liq. He plant (600W@4K, 80W@2K) Main Linac SRF (9-cell x 2 cavity) 19

20 Major Components for the cerl 300 kw, 30 kw Kly. 20 kw IOT FPGA-based LLRF Gun drive laser (1.3 GHz fiber laser) Radiation shield (1.5-m thick side, 1-m thick top) See for detail Proc. IPAC-2013, WEPWA015 (Sakanaka et al.) and references therein 20

21 1 st beam operation of cerl injector 1 st beam operation of cerl:april 2013 Buncher 500kV DC gun Diagnostic beamline Merger Injector Cryomodule Parameters of the Compact ERL Injector Gun voltage Beam energy Beam current Normalized rms emittance n = ( ) Bunch length (rms) 500 kv 5 10 MeV ma 1 mm mrad (77 pc/bunch) 0.1 mm mrad (7.7 pc/bunch) 1 3 ps ( mm) At the 1 st beam operation Beam current < 1 A (Gun drive laser with macro pulse mode) 21

22 Increasing the Beam Current (26, April) Beam current increased from 150 pa to 200 na (macropulse 1 s 1.6 ms) Successful beam transport to the dump without any beam loss. MS7 Dump MS6 B-mag MS5 MS4 MS3 Exit of SRF MS2 Entrance of SRF MS1 Gun Dump current(2.5 mv 200 na) FC current(2.5 mv 200 na) 22

23 Measurement of electron beam emittance We have confirmed a small emittance electron beam ( n < 1mm-mrad), which is essential to the high-brightness LCS gamma-ray. Further improvement seems possible by precise alignment of the electron beam in the injector accelerating cavities. S. Sakanaka et al., Proc. ERL

24 Requirements of the laser High-average power High-repetition rate Narrow bandwidth Precise synchronization 100W 81.25(162.5)MHz / 0 <10-3 <1ps Jitter Yb-fiber CPA laser is one of the most promising candidate 24

25 100W / MHz rep. rate yb-fiber CPA laser 2.6ps/nm 130ps/nm Target Courtesy of M. Mori 25

26 Laser Enhancement Cavity Several cavities have been developed at KEK for X-ray and -ray 4-mirror cavity at ATF 4-mirror cavity at STF T. Akagi et al., Proc. IPAC mirror cavity at LUCX Enhancement factor ~ 1000 is becoming reasonably achievable We are designing a cavity for cerl W laser x 1000 = 100 kw K. Sakaue et al., NIM A637 (2011) 26

27 Return loop is under construction (July - November, 2013) Schedule S. Sakanaka et al., Proc. ERL-2013 Jul. - Nov., 2013 : Construction of return loop Nov. (2nd half) : Conditioning of SC cavities Dec : Commissioning of cerl Dump Main linac Gun 1st arc 2nd arc South straight section st arc South straight section Alignment of magnets

28 LCS Experiment at the Compact ERL Upgrade for U-238 measurement (Just a Plan) Reinforcement of superconducting accelerator Addition of the 2 nd loop electron gun LCS experimental rooms Two superconducting accelerator (9-cell x 8 cavity) LCS gamma-rays on LCS chamber 238 U 2-loop Electron beam = 245 MeV, 10 ma Gamma-ray flux = 1x10 13 ph/s 28

29 Summary We have proposed non-destructive assay and detection of nuclear material by using laser Compton scattered gamma-rays. LCS demo. experiment is scheduled at the Compact ERL, a test facility of Energy Recovery Linac. Mode-locked laser of high-average power and enhancement cavity are critical components. We appreciate contributions from the laser community. 29