Measurement of the x-ray mass energy-absorption coefficient of air using 3 keV to 10 keV synchrotron radiation
Measurement of the x-ray mass energy-absorption coefficient of air using 3 keV to 10 keV synchrotron radiation
复制标题
使用 3 keV 至 10 keV 同步加速器辐射测量空气的 X 射线质量能量吸收系数
DOI：
10.1088/0031-9155/51/20/004
复制
发表时间：
2006
影响因子：
3.5
通讯作者：
M. Krumrey
中科院分区：
文献类型：
--
作者：
L. Büermann;B. Grosswendt;Kramer Hm;H. Selbach;M. Gerlach;M. Hoffmann;M. Krumrey
首次测量了能量范围为3 keV至10 keV的空气的绝对光子质量能量吸收系数，相对标准不确定度小于1%，明显小于迄今为止为计算数据假设的5%。单色同步辐射被用来测量总的辐射能量通过硅光电二极管校准对低温辐射计和沉积在干燥空气中的辐射能量的一部分，通过自由空气电离室。测量的电离电荷被转换成在空气中吸收的能量，通过计算有效的W值的光子作为其能量的函数的基础上的新的测量的W值在干燥的空气中的电子动能之间的1千电子伏和7千电子伏，也在这项工作中。测得的吸收系数进行了比较，与国家的最先进的计算，并发现同意在0.7%内的数据计算较早的哈贝尔在4千电子伏以上的能量，但发现不同的值高达2.1%，在10千电子伏从最近的计算塞尔策。
For the first time absolute photon mass energy-absorption coefficients of air in the energy range 3 keV to 10 keV have been measured with relative standard uncertainties less than 1%, significantly smaller than those of up to 5% assumed hitherto for calculated data. Monochromatized synchrotron radiation was used to measure both the total radiant energy by means of silicon photodiodes calibrated against a cryogenic radiometer and the fraction of radiant energy that is deposited in dry air by means of a free air ionization chamber. The measured ionization charge was converted into energy absorbed in air by calculated effective W values of photons as a function of their energy based on new measurements of the W values in dry air for electron kinetic energies between 1 keV and 7 keV, also presented in this work. The measured absorption coefficients were compared with state-of-the art calculations and found to agree within 0.7% with data calculated earlier by Hubbell at energies above 4 keV but were found to differ by values up to 2.1% at 10 keV from more recent calculations of Seltzer.