Derivation of V function for LR 115 SSNTD from its sensitivity to 220Rn in a diffusion chamber

Abstract

The sensitivity of the LR 115 detector inside a diffusion chamber to 220Rn gas concentration is dependent on the removed active layer thickness during chemical etching. This dependence is related to the V function for the LR 115 detector (where V is the ratio between the track etch velocity V t and the bulk etch velocity V b) and the geometry of the diffusion chamber. The present paper presents the experimentally determined relationship between the sensitivity of the LR 115 detector inside a Karlsruhe diffusion chamber (determined from the number of etched tracks completely penetrating the active cellulose nitrate layer) and the removed active layer thickness. These data were used to derive the V function for the LR 115 detector, which took the functional form of the Durrani-Green's function, i.e., V = 1 + (a 1 e - a2 R + a 3 e - a4 R) (1 - e - a5 R), with the best-fitted constants as a 1 = 14.50, a 2 = 0.50, a 3 = 3.9 and a 4 = 0.066. © 2006 Elsevier Ltd. All rights reserved.