Knowledge of the gas gain is important to optimise the design and the operating characteristics of tissue-equivalent proportional counters (TEPCs), especially for simulated sites smaller than 1 µm. TEPC area monitors of the order of centimetres must operate at very low gas pressure to simulate micrometric volumes, consequently the Townsend theory cannot be applied: effects related to the presence of an electric-field gradient become important and must be considered. A detailed description of the electron avalanche formation is complex, but in most practical cases an analytical formula can be used. The so-called gradient-field model includes three characteristic constants of the counting gas, which were already experimentally determined for propane-tissue equivalent (TE) and dimethyl ether (DME) gases. The aim of this work is to measure the gas-dependent parameters for propane gas. Preliminary results obtained with a spherical TEPC are presented.
|Journal||Radiation protection dosimetry|
|State||Published - 2 Feb 2014|
|Event||NEUDOS 2013 -12th Symposium on Neutron and Ion Dosimetry - IRSN- Institut de Radioprotection et de Sûreté Nucléaire, Aix-en-provence|
Duration: 3 Jun 2013 → 7 Jun 2013