Office of Nonproliferation and Verification Research and Development University and Industry Technical Interchange (UITI2011) Review Meeting

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1 Office of Nonproliferation and Verification Research and Development niversity and Industry Technical Interchange (ITI2011) Review Meeting Modeling of SNM Fission Signatures and December 7, 2011 Gennady Miloshevsky and Ahmed Hassanein Purdue niversity December 6-8, 2011

2 Outline Goals & Objectives MONSOL Code pgrade Simulations of Spontaneous & Induced Fission Chains Future Work & Summary 2

3 Principal Investigator: Ahmed Hassanein Co-Investigator: Gennady Miloshevsky Graduate Student: ue Yang Motivation for this project: two- and three-parameter analysis utilized in current neutron detectors: 1) total counts; 2) counts of correlated signal pairs; 3) number of signal events during fixed time interval multivariate statistics of energy, direction, multiplicity and arrival time of neutrons and γ-rays from an SNM source is a new set of many parameter data that can be utilized in novel organic-based neutron detectors such as MCP understanding the physical distinctions in the number-energy energy-direction- time correlations of SNM and cosmic neutrons and γ-rays with the goal to eliminate a non-snm counting in novel detectors 3

4 Overall goals and objectives of the research project: upgrade of our MONSOL code: the current state-of of-the-art of nuclear reactions, cross sections, radiation transport models for neutrons ns and γ-rays joint probability density functions (pdfs( pdfs) ) of the energy, direction, number and arrival time of neutrons and γ-rays evaluated from Monte Carlo (MC) simulations of their spontaneous and induced emissions from SNM sources joint pdfs of the number, energy, time and spatial distributions of neutrons ns and γ-rays produced by cosmic rays at a fission site evaluated from MC simulations probabilistic model to calculate joint pdfs of the number, energy, direction and arrival time of neutrons and γ-rays and uncertainties in SNM signatures due to fluctuations of cosmic-ray induced neutron background 4

5 Deliverables: Modeling of SNM Fission Signatures and MONSOL radiation transport code computer software for evaluations of the joint pdf of the number, energy, direction and arrival time of neutrons and γ-rays project report summarizing research methods and data collected during performance period evidence of workshop participations and peer-reviewed reviewed publications Technical challenges: practical realization, representation, and visualization of many parameter space for identifying, analyzing and understanding the specific features of SNM and non-snm signatures, covariance, and correlations of joint pdfs development of new probabilistic models for quick discrimination n between the characteristic SNM and non-snm signatures in novel detectors 5

6 The time schedule of the project tasks: Year 1 Year 2 Year 3 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Task 1.0 pdate Plan Task 2.0 Confirm personnel roles or hire new personnel Task 3.0 Project finance and accounting activities Task 4.0 MONSOL pgrade Task 5.0 MC simulations of neutron and γ-ray emissions from SNM fission sources Task 6.0 MC simulations of cascade showers generated by cosmic rays Task 7.0 Development of a probabilistic model Task 8.0 Analyze Data Task 9.0 Report on Data 6

7 MONSOL Code: MC radiation transport code developed under contracts ( ) with Electronstandart Institute (St Petersburg, Russia) for prediction of the radiation hardness of microcircuits on spacecrafts due to effects of ions, electrons, positrons, photons s and neutrons used in Efremov Institute (St( Petersburg, Russia) ) for modeling of the bulk energy deposition at the treatment of materials by wide electron beams used in Forschungszentrum Karlsruhe (Germany) to simulate the energy deposition by magnetized runaway electrons into divertor plates in ITER used within the framework of ISTC B23-96 project (Heat & Mass Transfer Institute, Minsk, Belarus) to model the passage of photon-electron and nuclear components of the cascade shower through the Earth atmosphere used in the niversity of New Mexico to study anode material erosion in high-power relativistic magnetrons 7

8 MONSOL Code pgrade: library of nuclear-model parameters, the Reference Input Parameter Library (RIPL-3), required for nuclear data evaluations detailed structure of discrete levels for , 235, 238, 238 P, 239 P, P and 242 integrated coupled-channels channels optical model, ECIS06: total, elastic, reaction, and direct inelastic cross sections, elastic and inelastic scattering angular distributions pre-equilibrium equilibrium particle emission: two-component exciton model equilibrium particle emission: Hauser-Feshbach model fission models: experimental, single- and double-humped fission, and the Wentzel-Kramers Kramers-Brillouin approximation transport of π-mesons: the link between photon-electron and nucleonic- nuclear components of cosmic radiation and also μ-mesons 242 P 8

9 MONSOL Code pgrade: nuclear chain reactions elastic fission elastic fission reactions 235 reactions elastic fission elastic reactions fission 9

10 MONSOL Code pgrade: detailed structure of discrete energy levels of excited states of SNM isotopes angular momentum, parity and isospin: quantum numbers characterizing each excited state of SNM isotopes Needed for accurate modeling: γ-ray decay of an excited state of SNM isotopes based on branching ratios inelastic neutron scattering on discrete energy levels with later decay of an exited state by gamma emission 10

11 MONSOL Code pgrade: neutron cross sections 235 reactions (n, n,γ) ) + (n,n( n,n ) ) + (n,xn+g,p,d,t,h,a( n,xn+g,p,d,t,h,a) 235 fission (n, n,γf) ) + (n,n( n,n f) ) + (n,xnf+g,p,d,t,h,a( n,xnf+g,p,d,t,h,a) 11

12 MONSOL Code pgrade: photon cross sections at photon energies <0.1 MeV, photoelectric absorption on atomic shells and Rayleigh scattering are dominating processes Compton scattering is important in the range 0.1< <3.0 MeV,, and electron-positron pair production on nuclei dominates at higher energies photonuclear absorption is more than order of magnitude lower compared to electron-positron pair production on nuclei 12

13 MONSOL Simulation: neutron and γ-ray tracks a bare ball of highly enriched uranium (HE) with radius of 3.97 cm interrogation by a source of 60 kev neutrons to induce fission chains in HE some long fission chains are only demonstrated in movie: neutron and photon trajectories are in yellow and blue; the burst of fissions is seen at some points 13

14 Multi-dimensional tables of joint-distribution representation: - neutrons - γ-rays - radii of spheres starting from the HE sphere: i = 1,2 I - range of polar angle on each of spheres: j = 1,2 J - range of azimuthal angle on each of spheres: k = 1,2 K - range of energy: l = 1,2 L - time (time gates): m = 0,1,2 M - multiplicity: n = 0,1,2 N 14

15 The post-processing processing code for the multivariate statistics: (under development) joint pdf: simultaneous behavior of six variables their joint observation marginal pdf: integrating out one of variables independence of variables: if joint pdf is a product of marginal pdfs conditional pdf: pdf of one variable when other variables are fixed covariance: degree to which variables move together strength of relation correlation: degree to which variables are linearly associated strength and direction of correlation apply separately to apply jointly to then to and to 15

16 Spontaneous fission of 235 Simulated neutron count from very low multiplying HE ball of radius 3.97 cm very low rate of spontaneous HE fission count rate from HE is much less or comparable to that from cosmic ray induced fission chains (Verbeke( et al., CRL-PROC PROC , 2007) cosmic ray background may fluctuate making passive detection of HE impossible 16

17 Spontaneous fission of 235 Energy spectra of neutrons & photons escaping from the HE ball of radius 3.97 cm; spectra are normalized by the number of escaped particles 17

18 Spontaneous fission of 235 Timelife of neutrons & photons within the HE ball of radius 3.97 cm; the start time is counted from a spontaneous fission event until produced particles leave the HE ball; spectra are normalized by the number of escaped particles 18

19 Interrogation of 235 by 60 kev neutrons Energy spectra of neutrons & photons escaping from the HE ball of radius 3.97 cm; spectra are normalized by the number of escaped particles 19

20 Interrogation of 235 by 7 MeV photons Energy spectra of neutrons & photons escaping from the HE ball of radius 3.97 cm; spectra are normalized by the number of escaped particles 20

21 Future work for the remainder of the project Year 1 Year 2 Year 3 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Task 1.0 pdate Plan Task 2.0 Confirm personnel roles or hire new personnel Task 3.0 Project finance and accounting activities Task 4.0 MONSOL pgrade Task 5.0 MC simulations of neutron and γ-ray emissions from SNM fission sources Task 6.0 MC simulations of cascade showers generated by cosmic rays Task 7.0 Development of a probabilistic model Task 8.0 Analyze Data Task 9.0 Report on Data 21

22 Summary MONSOL code is upgraded and adapted to perform MC simulations of the transport of neutrons and γ-rays from SNM and non-snm sources MC simulations of spontaneous and interrogation-induced induced emissions from SNM sources are partially accomplished; multi-dimensional tables of distributions of the number, energy, angle, and arrival time of neutrons and γ-rays are created development of the post-processing processing software is currently in progress for evaluations of multivariate statistics of joint pdfs of the number, energy, angle and arrival time of neutrons and γ-rays emitted from SNM sources using multi-dimensional tables two manuscripts are in preparation on spontaneous and induced emissions e from SNM sources to be submitted to Nuclear Instruments and Methods in Physics Research A 22