Large area bismuth absorbers for X-ray microcalorimeters
Large area bismuth absorbers for X-ray microcalorimeters
复制标题
X 射线微量热计用大面积铋吸收体
DOI：
10.1016/j.nima.2003.11.231
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
C. Stahle
中科院分区：
文献类型：
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作者：
J. Vaillancourt;C. Allen;R. Brekosky;A. Dosaj;M. Galeazzi;R. Kelley;D. Liu;D. McCammon;F. Porter;L. Rocks;W. Sanders;C. Stahle
使用大面积（2 mm ×2 mm）铋吸收体进行微量热测量所面临的两个挑战是铋的热容的不确定性以及由于吸收体的大尺寸而引起的横向热传导和位置依赖性的影响。我们测量了三个Bi样品在100 mK时的热容为0.3 - 0.6 J K-1 m-3。这些吸收体还表现出响应变化，因为在吸收体边缘处由X射线事件产生的声子将比在吸收体中心处的声子花费更长的时间传播到温度计附接点。如果与温度计时间常数相比，传播时间不是很短，则这种效应可能会降低检测器的能量分辨率。我们发现，最大的吸收体的响应变化的0.4%，在其整个区域。
Two challenges facing the use of large area (2 mm ×2 mm ) bismuth absorbers for microcalorimetry are uncertainties in the heat capacity of bismuth and the effects of lateral heat conduction and position dependence due to the absorber's large size. We have measured the heat capacity of three Bi samples to be 0.3−0.6 J K−1m−3at 100 mK . These absorbers also exhibit response variations as phonons created by an X-ray event at an absorber edge will take longer to propagate to the thermometer attachment point than those at the absorber center. This effect may degrade the detector's energy resolution if the propagation time is not very short compared to the thermometer time constant. We show that the response of the largest absorber varies by ∼4% across its area.