2026-09-19T18:55:46Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/1395922022-01-15T03:44:48Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023
Danagoulian, Areg
Naqvi, Farheen
Bickus, Jacob E.
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
2022-01-14T15:22:02Z
2022-01-14T15:22:02Z
2021-06
2021-07-08T14:00:03.303Z
https://hdl.handle.net/1721.1/139592
A number of fields in nuclear security require isotopic analysis and identification. Nuclear resonance fluorescence(NRF) has provided a non-intrusive isotope-sensitive measurement technique to detect special nuclear material in cargo [8], and has been proposed to be used as a verification technique in arms control treaty verification [41]. Standard methods of performing NRF involve the use of expensive HPGe detectors to detect a scattered signal to discriminate between isotopes of special nuclear materials. Furthermore these require a continuous wave (CW) beam, which currently can be delivered only by large and static accelerators [40]. We propose a system using an energy-modulating chopper wheel and a simpler, pulsed electron accelerator beam as the radiation source. This work builds upon a concept presented by Kemp et al. [24], with the difference of a measurement of NRF in a scattering mode. In this approach the chopper wheel serves as a switch effectively modulating the beam to include or exclude photons of NRF energies for interrogating the test object. Comparison between the chopper "On" and "Of" will provide a differential signal which upon integration can allow inference of special nuclear materials based on their NRF signals. The approach places integrating calorimetric Cherenkov detectors at a back-scattered angle which will eliminate much of the background typically found in a transmitted spectra. Cherenkov detectors will replace the HPGe detectors in effort to decrease the low energy background. We present a thoroughly tested Monte Carlo model to compare with experimental testing using Cherenkov detectors and nuclear resonance fluorescence to discriminate between isotopes of special nuclear material. Preliminary simulation results show that a uranium interrogation object could not be determined within a 5 minute interrogation.
S.M.
Massachusetts Institute of Technology
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http://rightsstatements.org/page/InC-EDU/1.0/
Monte Carlo Method for Calorimetric NRF Cargo Screening
Thesis
application/pdf
Master
Master of Science in Nuclear Science and Engineering
Publication
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unknown
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<Abstract>A number of fields in nuclear security require isotopic analysis and identification. Nuclear resonance fluorescence(NRF) has provided a non-intrusive isotope-sensitive measurement technique to detect special nuclear material in cargo [8], and has been proposed to be used as a verification technique in arms control treaty verification [41]. Standard methods of performing NRF involve the use of expensive HPGe detectors to detect a scattered signal to discriminate between isotopes of special nuclear materials. Furthermore these require a continuous wave (CW) beam, which currently can be delivered only by large and static accelerators [40]. We propose a system using an energy-modulating chopper wheel and a simpler, pulsed electron accelerator beam as the radiation source. This work builds upon a concept presented by Kemp et al. [24], with the difference of a measurement of NRF in a scattering mode. In this approach the chopper wheel serves as a switch effectively modulating the beam to include or exclude photons of NRF energies for interrogating the test object. Comparison between the chopper "On" and "Of" will provide a differential signal which upon integration can allow inference of special nuclear materials based on their NRF signals. The approach places integrating calorimetric Cherenkov detectors at a back-scattered angle which will eliminate much of the background typically found in a transmitted spectra. Cherenkov detectors will replace the HPGe detectors in effort to decrease the low energy background. We present a thoroughly tested Monte Carlo model to compare with experimental testing using Cherenkov detectors and nuclear resonance fluorescence to discriminate between isotopes of special nuclear material. Preliminary simulation results show that a uranium interrogation object could not be determined within a 5 minute interrogation.</Abstract>
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