VanMeter P, Delgado-Aparicio L F, Reusch L, Pablant N, Maddox J, Rissi M, Luethi B, Donath T, Schulze-Briese C, Hill K, Den Hartog D
Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Princeton Plasma Physics Laboratory (PPPL), Princeton, New Jersey 08540, USA.
Rev Sci Instrum. 2018 Oct;89(10):10G119. doi: 10.1063/1.5037347.
A multi-energy soft x-ray pin-hole camera based on the PILATUS3 100 K x-ray detector has recently been installed on the Madison Symmetric Torus. This photon-counting detector consists of a two-dimensional array of ∼100 000 pixels for which the photon lower-threshold cutoff energy can be independently set for each pixel. This capability allows the measurement of plasma x-ray emissivity in multiple energy ranges with a unique combination of spatial and spectral resolution and the inference of a variety of important plasma properties (e.g., , , ). The energy dependence of each pixel is calibrated for the 1.6-6 keV range by scanning individual trimbit settings, while the detector is exposed to fluorescence emission from Ag, In, Mo, Ti, V, and Zr targets. The resulting data for each line are then fit to a characteristic "S-curve" which determines the mapping between the 64 possible trimbit settings for each pixel. The statistical variation of this calibration from pixel-to-pixel was explored, and it was found that the discreteness of trimbit settings results in an effective threshold resolution of Δ < 100 eV. A separate calibration was performed for the 4-14 keV range, with a resolution of Δ < 200 eV.
一台基于PILATUS3 100K X射线探测器的多能量软X射线针孔相机最近已安装在麦迪逊对称环面装置上。这种光子计数探测器由一个约100000像素的二维阵列组成，每个像素的光子低阈值截止能量可独立设置。这种能力使得能够在多个能量范围内测量等离子体X射线发射率，具备独特的空间和光谱分辨率组合，并能推断出各种重要的等离子体特性（例如， ， ， ）。通过扫描各个微调位设置，在探测器暴露于银、铟、钼、钛、钒和锆靶的荧光发射时，对1.6 - 6 keV能量范围内每个像素的能量依赖性进行校准。然后将每行的所得数据拟合到一条特征“s曲线”，该曲线确定每个像素64种可能的微调位设置之间的映射关系。研究了这种校准在像素间的统计变化，发现微调位设置的离散性导致有效阈值分辨率Δ < 100 eV。对4 - 14 keV能量范围进行了单独校准，分辨率为Δ < 200 eV。
