Nuclear Techniques ›› 2018, Vol. 41 ›› Issue (1): 10403-010403.doi: 10.11889/j.0253-3219.2018.hjs.41.010403

• NUCLEAR ELECTRONICS AND INSTRUMENTATION • Previous Articles     Next Articles

Accurate measurement of 131Xem activity concentration by internal gas proportional counting system

LI Qi, WANG Shilian, FAN Yuanqing, ZHAO Yungang, ZHANG Xinjun, JIA Huaimao, LIU Shujiang, CHANG Yinzhong   

  1. CTBT Beijing National Data Centre and Radionuclide Laboratory, Beijing 100085, China
  • Received:2017-10-23 Revised:2017-11-12 Online:2018-01-10 Published:2018-01-06
  • Supported by:

    Supported by Young Scientists Fund of National Natural Science Foundation of China (No.11505082)

Abstract:

Background: Due to the chemical inertness, the noble gases escape more easily from underground nuclear explosions into atmosphere than the fission products in solid form. Among the noble gases, four of radioxenon isotopes, i.e. 131Xem, 133Xem, 133Xe and 135Xe, have high fission yields with half-lives of several hours to several days, which can be detected after long distances diffusion from where they were released. So these four radioxenon isotopes play a key role for underground nuclear test monitoring compliance with comprehensive nuclear-test-ban treaty (CTBT). Accurate measurement of radioxenon isotopes activities is a key technique to identify characteristic of nuclear test from the monitoring data. Purpose: Radioxenon isotopes activities are usually determined using relative measurement methods-HPGe γ spectrometers or β-γ coincidence systems. The detection efficiency calibration of the relative measurement system by standard samples is the critical factor of these relative measurement methods. Methods: This article describes the process and method of accurate measurement of activity concentration of 131Xem by internal gas proportional counting system which adopted length-compensated method. Results: The activity concentration of 131Xem is determined to be (1.75±0.01) Bq·mL–1 using internal gas proportional counters with corrections for dead time, background, discrimination, end effects and wall effects. Conclusion: The activity concentration of 131Xem sample was measured accurately, which can be used to calibrate detection efficiency of relative measurement system as a standard sample.

Key words: Radioxenon isotopes, Activity concentration, Internal gas proportional counter

CLC Number: 

  • TL816.4