Organic scintillation detector response simulation using non-analog MCNPX-PoliMi

Conference · Sun Jul 01 00:00:00 EDT 2012

OSTI ID:22105839

Prasad, S.; Clarke, S. D.; Pozzi, S. A.; Larsen, E. W. ^[1]

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1. Univ. of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48109 (United States)

Organic liquid scintillation detectors are valuable for the detection of special nuclear material since they are capable of detecting both neutrons and gamma rays. Scintillators can also provide energy information which is helpful in identification and characterization of the source. In order to design scintillation based measurement systems appropriate simulation tools are needed. MCNPX-PoliMi is capable of simulating scintillation detector response; however, simulations have traditionally been run in analog mode which leads to long computation times. In this paper, non-analog MCNPX-PoliMi mode which uses variance reduction techniques is applied and tested. The non-analog MCNPX-PoliMi simulation test cases use source biasing, geometry splitting and a combination of both variance reduction techniques to efficiently simulate pulse height distribution and then time-of-flight for a heavily shielded case with a {sup 252}Cf source. An improvement factor (I), is calculated for distributions in each of the three cases above to analyze the effectiveness of the non-analog MCNPX-PoliMi simulations in reducing computation time. It is found that of the three cases, the last case which uses a combination of source biasing and geometry splitting shows the most improvement in simulation run time for the same desired variance. For pulse height distributions speedup ranging from a factor 5 to 25 is observed, while for time-of-flights the speedup factors range from 3 to 10. (authors)

• Research Organization: American Nuclear Society, Inc., 555 N. Kensington Avenue, La Grange Park, Illinois 60526 (United States)
• OSTI ID: 22105839
• Resource Relation: Conference: PHYSOR 2012: Conference on Advances in Reactor Physics - Linking Research, Industry, and Education, Knoxville, TN (United States), 15-20 Apr 2012; Other Information: Country of input: France; 7 refs.
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
22 GENERAL STUDIES OF NUCLEAR REACTORS
CALCULATION METHODS
CALIFORNIUM 252
DESIGN
GAMMA RADIATION
GEOMETRY
LIQUID SCINTILLATION DETECTORS
NEUTRON DETECTORS
NEUTRONS
PHOSPHORS
PROLIFERATION
PULSES
RADIOACTIVE MATERIALS
SCINTILLATIONS
SIMULATION
TIME-OF-FLIGHT METHOD