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Title: In-depth evaluation of 252 Cf absolute calibration by passive neutron correlation counting method

Abstract

252Cf neutron sources are particularly convenient, and therefore widely used, to characterize and calibrate many kinds of neutron detectors for both scientific and technological applications. An emerging interest is the use of 252Cf to calibrate neutron correlation counters for the verification and assay of Pu-items as part of the international effort to safeguard nuclear materials. Passive neutron correlation counting (PNCC) methods, combined with knowledge of the fission neutron multiplicity distribution, can be used as an absolute technique to determine the neutron emission rate of 252Cf sources. This means that common equipment used by the safeguards community can, in principle, be used to self-certify, to high accuracy, the strength of physically small 252Cf sealed sources for use in calibration. This is the first step in using 252Cf in place of extensive Pu reference materials for experimental calibration by the safeguards community. The theoretical foundation is already clear but the present work presents the first systematic attempt at demonstrating the practical utility of the concept across a variety of typical instruments. We compare four emission rate estimators for four detector configurations on a common source previously certified by the MnSO 4-bath technique. We find that the estimator based on the singles tomore » doubles rate ratio provides consistent and precise results across all of the instruments and that these agree with the MnSO 4-bath technique within combined uncertainties. This success suggests that the absolute PNCC method could become a technically defensible and commonly used, method capable of sub 1% accuracy for routine calibration work.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1544724
Report Number(s):
LA-UR-18-27775
Journal ID: ISSN 0026-1394
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Accepted Manuscript
Journal Name:
Metrologia
Additional Journal Information:
Journal Volume: 56; Journal Issue: 1; Journal ID: ISSN 0026-1394
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS

Citation Formats

Henzlova, Daniela, Favalli, Andrea, and Croft, Stephen. In-depth evaluation of 252 Cf absolute calibration by passive neutron correlation counting method. United States: N. p., 2019. Web. doi:10.1088/1681-7575/aaf5a4.
Henzlova, Daniela, Favalli, Andrea, & Croft, Stephen. In-depth evaluation of 252 Cf absolute calibration by passive neutron correlation counting method. United States. doi:10.1088/1681-7575/aaf5a4.
Henzlova, Daniela, Favalli, Andrea, and Croft, Stephen. Fri . "In-depth evaluation of 252 Cf absolute calibration by passive neutron correlation counting method". United States. doi:10.1088/1681-7575/aaf5a4. https://www.osti.gov/servlets/purl/1544724.
@article{osti_1544724,
title = {In-depth evaluation of 252 Cf absolute calibration by passive neutron correlation counting method},
author = {Henzlova, Daniela and Favalli, Andrea and Croft, Stephen},
abstractNote = {252Cf neutron sources are particularly convenient, and therefore widely used, to characterize and calibrate many kinds of neutron detectors for both scientific and technological applications. An emerging interest is the use of 252Cf to calibrate neutron correlation counters for the verification and assay of Pu-items as part of the international effort to safeguard nuclear materials. Passive neutron correlation counting (PNCC) methods, combined with knowledge of the fission neutron multiplicity distribution, can be used as an absolute technique to determine the neutron emission rate of 252Cf sources. This means that common equipment used by the safeguards community can, in principle, be used to self-certify, to high accuracy, the strength of physically small 252Cf sealed sources for use in calibration. This is the first step in using 252Cf in place of extensive Pu reference materials for experimental calibration by the safeguards community. The theoretical foundation is already clear but the present work presents the first systematic attempt at demonstrating the practical utility of the concept across a variety of typical instruments. We compare four emission rate estimators for four detector configurations on a common source previously certified by the MnSO4-bath technique. We find that the estimator based on the singles to doubles rate ratio provides consistent and precise results across all of the instruments and that these agree with the MnSO4-bath technique within combined uncertainties. This success suggests that the absolute PNCC method could become a technically defensible and commonly used, method capable of sub 1% accuracy for routine calibration work.},
doi = {10.1088/1681-7575/aaf5a4},
journal = {Metrologia},
number = 1,
volume = 56,
place = {United States},
year = {2019},
month = {1}
}

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Works referenced in this record:

International key comparison of measurements of neutron source emission rate (1999–2005): CCRI(III)-K9.AmBe
journal, January 2011


Determining 252Cf source strength by absolute passive neutron correlation counting
journal, June 2013

  • Croft, S.; Henzlova, D.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 714
  • DOI: 10.1016/j.nima.2013.02.002

Coincidence Gate Utilization Factors for Neutron Correlation Counters With Up to Three Components in the Die-Away Profile
conference, May 2009

  • Croft, S.; McElroy, R. D.; Kane, S. C.
  • The 11th International Conference on Environmental Remediation and Radioactive Waste Management, 11th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B
  • DOI: 10.1115/ICEM2007-7173