Chiriotti S, Moro D, Colautti P, Conte V, Grosswendt B
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 Laboratori Nazionali di Legnaro, INFN-LNL, Legnaro, Italy
Laboratori Nazionali di Legnaro, INFN-LNL, Legnaro, Italy.
Radiat Prot Dosimetry. 2015 Sep;166(1-4):242-6. doi: 10.1093/rpd/ncv293. Epub 2015 May 4.
A tissue-equivalent proportional counter (TEPC) simulates micrometric volumes of tissue if the energy deposited in the counter cavity is the same as that in the tissue volume. Nevertheless, a TEPC measures only the ionisations created in the gas, which are later converted into imparted energy. Therefore, the equivalence of the simulated diameter (Dρ) in two gases should be based on the equality of the mean number of ions pairs in the gas rather than on the imparted energy. Propane-based tissue-equivalent gas is the most commonly used gas mixture at present, but it has the drawback that its composition may change with time. From this point of view, the use of pure propane offers practical advantages: higher gas gain and longer stability. In this work, microdosimetric measurements performed with pure propane, at site sizes 0.05 mg cm(-2) ≤ Dρ ≤ 0.3 mg cm(-2), demonstrate that the response of a propane-filled detector in gamma and in neutron fields is almost the same if an appropriate gas density is used.
如果沉积在计数管腔中的能量与组织体积中的能量相同，那么组织等效正比计数器（TEPC）就能模拟微米级的组织体积。然而，TEPC仅测量气体中产生的电离，这些电离随后被转换为授予能量。因此，两种气体中模拟直径（Dρ）的等效性应基于气体中离子对平均数的相等，而不是授予能量。丙烷基组织等效气体是目前最常用的气体混合物，但它有一个缺点，即其成分可能随时间变化。从这一角度来看，使用纯丙烷具有实际优势：更高的气体增益和更长的稳定性。在这项工作中，使用纯丙烷在0.05 mg cm(-2) ≤ Dρ ≤ 0.3 mg cm(-2)的场点尺寸下进行的微剂量测量表明，如果使用适当的气体密度，充丙烷探测器在γ和中子场中的响应几乎相同。
