Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2015, Vol. 26 ›› Issue (2): 020402 doi: 10.13538/j.1001-8042/nst.26.020402


Variance analysis for passive neutron multiplicity counting

CHEN Li-Gao (陈利高),1, 2 GONG Jian (龚建),1, y WANG Kan (王侃),2 XIE Qi-Lin (谢奇林),1 LIU Xiao-Bo (刘晓波),1 BAI Zhong-Xiong (白忠雄),1 LU Yi (鲁艺),1 RONG Ru (荣茹),1 and YIN Yan-Peng (尹延朋)1   

  1. 1Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
    2Department of Engineering Physics, Tsinghua University, Beijing 100084, China
  • Contact: GONG Jian
  • Supported by:

    Supported by the National Natural Science Foundation of China
    (No. 11375158), Science and Technology Development Foundation of
    CAEP (No. 2013B0103009)

CHEN Li-Gao, GONG Jian, WANG Kan, XIE Qi-Lin, LIU Xiao-Bo, BAI Zhong-Xiong, RONG Ru, and YIN Yan-Peng . Variance analysis for passive neutron multiplicity counting.Nuclear Science and Techniques, 2015, 26(2): 020402     doi: 10.13538/j.1001-8042/nst.26.020402


Passive neutron multiplicity counting is widely used as a nondestructive assay technique to quantify mass of
plutonium material. One goal of this technique is to achieve good precision in a short measurement time. In
this paper, we describe a procedure to derive mass assay variance for multiplicity counting based on the threeparameter
model, and analytical equations are established using the measured neutron multiplicity distribution.
Monte Carlo simulations are performed to evaluate precision versus plutonium mass under a fixed measurement
time with the equations. Experimental data of seven weapons-grade plutonium samples are presented to test
the expected performance. This variance analysis has been used for the counter design and optimal gate-width
setting at Institute of Nuclear Physics and Chemistry.

Key words: Arms control and disarmament, Neutron multiplicity counting, Variance analysis, Plutonium, Neutron counting