222Rn detection efficiency and sensitivity coefficient of the LR 115-II nuclear track detector

Radon activity concentrations in air were measured by the Kodak-Pathé LR 115-II nuclear track detector. Using the calibrated sensitivity coefficient of the detector (k = 0.0285 Bq-1 m3 tr cm-2 d-1 = 0.33 cm), the critical detection angle was calculated. In the alpha-particle energy region of 1-3.7 MeV, the detector efficiency for 241Am was near 32% but the 222Rn detector efficiency was 23%. The permeability constant of the detector paper filter was measured in a standard radon atmosphere and a value of 9.08 x 10(-6) cm2 s-1 was obtained.