Abstract

Ultralow background gamma-ray measurement system was installed to measure and analyze gamma-rays emitted from environmental and swipe samples. The background reduction techniques applied on this system are the passive shielding to surround the HPGe detector, an active external anticosmic shield to shield cosmic-rays and the nitrogen gas supply to minimize the introduction of ubiquitous radon decay nuclei. The performance test result showed that the system background at energies between 50 keV and 2 MeV is reduced about $10^{-2}$ order and the MDA is so low as to be suitable for the environmental sample analysis. But it is appeared that the neutron produced by cosmic-ray increases the background at low energy region.

Keywords

• Ultralow background gamma-ray measurement system;
• Anticoincident;
• Environmental sample;
• Cosmic-ray

• 극피준위 백그라운드 감마선 측정시스템;
• 역동시;
• 환경시료;
• 우주선;

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