Improvement of a cryogenic radiometer for XFEL absolute intensity measurement
Improvement of a cryogenic radiometer for XFEL absolute intensity measurement
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DOI：
10.1016/j.nima.2011.08.039
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发表时间：
2011-12-11
影响因子：
1.4
通讯作者：
Shiraiwa, S.
中科院分区：
文献类型：
--
作者：
Tanaka, T.;Kato, M.;Shiraiwa, S.
改进了低温辐射计，用于测量超短脉冲强辐射X射线自由电子激光的绝对辐射功率。基于蒙特卡罗程序EGS5的模拟结果，研制了一种新型的低温辐射计空腔吸收体。模拟结果表明，新的空腔吸收体实现了吸收率接近1的硬X射线高达40键的光子能量。通过对两种不同类型的硅光电二极管的校准，证实了新腔吸收体的优异性能，以及新腔和前腔之间的一致性。校准结果在其相对扩展的不确定度范围内一致。为了确认新的腔体吸收器在高辐射功率区域的性能，还比较了用低温辐射计和X射线束监视器获得的辐射功率。获得了两个探测器之间的强相关性。与新的腔吸收体，绝对辐射功率的XFEL光子能量高达40千电子伏，低不确定性预计将被测量。(C)2011 Elsevier B.V.保留所有权利。
A cryogenic radiometer was improved for measurements of the absolute radiant power of x-ray Free Electron Laser, which provides intense radiation with an ultra-short pulse duration. Based on simulation results obtained by the Monte Carlo program EGS 5 code, a new cavity absorber of the cryogenic radiometer was developed. The simulation results show that the new cavity absorber achieves absorptance close to unity for hard x-rays up to photon energies of 40 key. The excellent performance of the new cavity absorber, as well as the consistency between the new and the former cavity, was confirmed by calibrating two different types of silicon photodiodes. The calibration results agreed well within their relative expanded uncertainties. To confirm the performance of the new cavity absorber in the high radiant power region, the radiant powers obtained with the cryogenic radiometer and an x-ray beam monitor were also compared. A strong correlation between the two detectors was obtained. With the new cavity absorber, the absolute radiant power of XFEL for photon energies of up to 40 keV with low uncertainties is expected to be measured. (C) 2011 Elsevier B.V. All rights reserved.