Toxicologie environnementale et analytique

Calibration Factor for LR 115 Type II Detectors Used to Measure Indoor ²²⁰Rn

Abstract

Nguyen Thi Thu Ha, Trinh Van Giap, Nguyen Van Khanh, Le Dinh Cuong, Pham Bao Ngoc and Nguyen Thi Oanh

Major aim of the paper is to determine calibration factor for LR 115 type II detectors used to measure indoor 220Rn . To determine calibration factor, LR 115 detectors were fixed on top and bottom inside urban cup chamber and sent to NIRS, Japan to 220Rn calibration exposure. After detectors have been calibration exposure at NIRS, authors carried out following all steps of procedure, which set up at laboratory in INST, Vietnam. This paper discusses the experimental method that is used in calculating the calibration factor of 220Rn inside the urban cup, calibration factors (CF) were determined by experimental with detectors placed at top and bottom inside urban cup were 0.023 ± 0.004 and 0.038 ± 0.007(tracks.cm-2/Bq.m-3.d), respectively. The curve between integrated 220Rn concentration and tracks density with factor R2=0.96 and 0.97 at top and bottom inside urban cup, respectively. In order to precision evaluation, authors used 20 couple of LR-115 detectors at 8cm detector-source distance with relative standard deviation less than 1.48%.