Moro D, Chiriotti S, Colautti P, Conte V
Laboratori Nazionali di Legnaro, INFN-LNL, Legnaro, Italy
Laboratori Nazionali di Legnaro, INFN-LNL, Legnaro, Italy Belgian Nuclear Research Centre, SCK•CEN, Mol, Belgium Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain (UCL), Brussels, Belgium.
Radiat Prot Dosimetry. 2014 Oct;161(1-4):459-63. doi: 10.1093/rpd/ncu005. Epub 2014 Feb 2.
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.
了解气体增益对于优化组织等效正比计数器（TEPC）的设计和运行特性非常重要，特别是对于模拟小于1 µm的区域。面积为厘米量级的TEPC面积监测器必须在非常低的气压下运行以模拟微米级体积，因此汤森理论不适用：与电场梯度存在相关的效应变得很重要，必须加以考虑。电子雪崩形成的详细描述很复杂，但在大多数实际情况下可以使用一个解析公式。所谓的梯度场模型包括计数气体的三个特征常数，这些常数已经通过实验确定了丙烷-组织等效（TE）和二甲醚（DME）气体的相关值。这项工作的目的是测量丙烷气体的气体相关参数。本文展示了使用球形TEPC获得的初步结果。
