论文部分内容阅读
长期以来,对高能光子和电子束吸收剂最的测量,是采用~(60)Coγ射线或2MVX射线,对电离室剂量仪表进行照射量校准,再用转换因子(C_λ,C_E)换算成水中某点的吸收剂量。七十年代末,许多物理学家对该法经过研究,提出了质疑。主要有:1.该方法假定,电离室及静电计在国家标准实验室~(60)Co或2MVX射线辐射场中比对后,得出空气中照射量校准因子Nc,在电离室用于体模中“照射量”测量时仍不变。这一假定忽略了电离室在体模中的位置以及辐射质大小所引起的散射线的影响。2.以往规程忽略了C_λ、C_E值所依据的次级电子能
For a long time, the most measurement of high-energy photon and electron beam absorber is to calibrate the irradiation dose of ionization chamber dose meter with ~ (60) Coγ ray or 2MVX ray and then convert it into water by a conversion factor (C_λ, C_E) The point of absorbed dose. In the late seventies, many physicists questioned the law. Mainly include: 1. This method assumes that the ionization chamber and the electrometer in the national standard laboratory ~ (60) Co or 2MVX radiation field comparison, come to the air exposure calibration factor Nc, the ionization chamber for the body Mold “exposure” measurement is still the same. This assumption ignores the ionization chamber in the phantom of the position and the size of the radiation caused by the impact of scattered lines. 2. In the past, the rules neglected the secondary electron energy on which C_λ and C_E values are based