Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
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Neutron Induced Capture Gamma Spectroscopy Sonde Design and Response Analysis Based on Monte Carlo Simulation

Monte Carlo 시물레이션에 기초한 포획모드 중성자-감마 스펙트럼 존데 설계 및 반응 분석

  • Won, Byeongho (Heesong Geotek Co., Ltd.) ;
  • Hwang, Seho (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Shin, Jehyun (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Kim, Jongman (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Kim, Ki-Seog (Heesong Geotek Co., Ltd.) ;
  • Park, Chang Je (Department of Nuclear Engineering, Sejong University)
  • 원병호 ((주)희송지오텍) ;
  • 황세호 (한국지질자원연구원 지구환경연구본부) ;
  • 신제현 (한국지질자원연구원 지구환경연구본부) ;
  • 김종만 (한국지질자원연구원 지구환경연구본부) ;
  • 김기석 ((주)희송지오텍) ;
  • 박창제 (세종대학교 원자력공학과)
  • Received : 2015.08.05
  • Accepted : 2015.08.21
  • Published : 2015.08.31
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Abstract

For efficiently designing neutron induced gamma spectroscopy sonde, Monte Carlo simulation is employed to understand a dominant location of thermal neutron and classify the formation elements from the energy peak of capture gamma spectrum. A pulsed neutron generator emitting 14 MeV neutron particles was used as a source, and flux of thermal neutron was calculated from the twelve detectors arranged at each 10 cm intervals from the source. Design for reducing borehole effects using shielding materials was also applied to numerical sonde model. Moreover, principal elements and quantities of numerical earth models were verified through the energy spectrum analysis of capture gamma detected from a gamma detector. These results can help to enhance the signal-to-noise ratio, and determine an optimal placement of capture gamma detectors of neutron induced gamma spectroscopy sonde.

본 연구에서는 중성자-감마 스펙트럼검층 존데 설계를 목적으로 Monte Carlo 시물레이션을 이용하여 열중성자 반응의 우세한 영역 파악 및 포획감마 스펙트럼의 에너지피크 값에 기초한 지층 구성 원소 구분을 수행하였다. 14 MeV 에너지준위의 중성자를 방출하는 중성자발생장치를 선원으로 이용하여 선원으로부터 10 cm 간격으로 12개의 중성자 검출기들을 배열함으로써 거리에 따른 열중성자 양을 측정하였다. 시추공 영향 저감을 위해 존데모형에 차폐재를 적용하여 보다 정확한 열중성자 측정을 수행하여 열중성자 반응이 우세한 위치를 분석한 뒤, 이 위치에서 검출된 포획감마 에너지 스펙트럼을 분석하여 지층을 구성하는 주요 원소 및 그 양을 확인하였다. 본 연구 결과는 중성자-감마 스펙트럼검층 존데의 신호대잡음 비 향상과 포획감마 검출기 최적 위치 선정에 도움이 될 것으로 판단된다.

Keywords

References

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