This paper describes a simple method to reduce the radon background component applied in environmental studies using gamma spectrometry. The radon component can be reduced by introducing either nitrogen gas or clean air into the detector chamber in order to create a positive pressure and further minimize radon intrusion from outside. | Science & Technology Development, Vol 19, Improvement of the detection limit by radon background reduction method Tran Thien Thanh Chau Van Tao University of Science, VNU-HCM Laurent Ferreux Marie Christine Lépy CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB) (Received on 3rdMarch 2016, accepted on 2th December 2016) ABSTRACT This paper describes a simple method to radon intrusion from outside. This method shows reduce the radon background component applied that we can minimize the influence of radon in environmental studies using gamma daughter background such as 214Pb, 214Bi and 210 spectrometry. The radon component can be Pb (from 238U), 212Pb, 212Bi and 208Tl (from 232 reduced by introducing either nitrogen gas or Th). By the way, the detection limit of the clean air into the detector chamber in order to gamma spectrometry is discussed. create a positive pressure and further minimize Keywords: gamma spectrometry, limit detection, background INTRODUCTION There are many efforts to the issues such as to look for the proper shielding materials for better detector housing and so on. Techniques developed so far for rare event research, dark matter search in particle and nuclear physics research are well known. In this research we would like to investigate the most suitable and sensitive technique for fixing the background origin in the materials. To improve the detection limits in low level activity measurements, the background has to be reduced as much as possible. The background spectrum of a germanium detector is due to a combination of different components such as environmental gamma radiation, radioactivity in the construction material of the detector, radio impurities in the shield, cosmic rays and radon gas. The first three contributions can be reduced drastically by means of a suitable passive shielding made of old or very low – activity lead and by a careful selection of materials Trang 126 surrounding the crystal. The .
