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

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 + (a₁ e^{- a2 R} + a₃ e^{- a4 R}) (1 - e^{- a5 R}), with the best-fitted constants as a₁ = 14.50, a₂ = 0.50, a₃ = 3.9 and a₄ = 0.066. © 2006 Elsevier Ltd. All rights reserved.