Nuclear Techniques ›› 2014, Vol. 37 ›› Issue (05): 50205-050205.doi: 10.11889/j.0253-3219.2014.hjs.37.050205

• LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS • Previous Articles     Next Articles

Monte Carlo simulation of polycrystalline airborne γ-ray spectrometer for ground radiation monitoring

GONG Chunhui1,2 ZENG Guoqiang1 GE Liangquan1 TANG Xiaobin2 TAN Chengjun1   

  1. 1(College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China) 2(Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
  • Received:2013-12-19 Revised:2014-01-29 Online:2014-05-10 Published:2014-05-08

Abstract:

Background: Airborne γ-ray spectrometer has been used extensively over several decades for mineral exploration and geological mapping purposes to look for the peaks of potassium, uranium and thorium. And the low-energy ray is ignored. Purpose: In order to provide a basis for obtaining effective environmental radioactivity measurement results, Minimum detectable activity (MDA) values in monitoring ground radiation of the polycrystalline airborne γ-ray spectrometer need to be calculated. Methods: MDA is related with the detection efficiency. A Monte Carlo simulation was performed using the MCNP5 code for different radionuclides in the ground environment. Equivalent mass thickness was proposed to reduce variance, and the secondary source was used in the MCNP5 input. Results: The pulse height distributions of external detectors and internal detectors for 137Cs and 131I at different heights were obtained, which represent the counting rate decreased as the altitude increases. And the MDA of external detectors is better than that of internal detectors. Conclusion: The external detector is suggested to adopt in flight measurement for enhancing MDA.

Key words: Polycrystalline airborne gamma-ray spectrometer, Monte Carlo, Gaussian broadening, Minimum detectable activity (MDA)