标题： SVOM任务上微通道X射线望远镜的光谱性能 显示英文标题

标题： Spectral performance of the Microchannel X-ray Telescope on board the SVOM mission

摘要： 微通道X射线望远镜（MXT）是SVOM天文任务上一种创新的紧凑型X射线仪器，专门用于研究瞬变现象，如伽马射线暴。 在3周内，我们在Panter X射线测试设施中，在MXT在轨期间将经历的常规温度和真空条件下对MXT飞行模型进行了测试。 我们在一系列特征能量下收集了数据，以探测整个MXT能量范围，从0.28 keV到9 keV，并针对多个光源位置进行测量，其中点扩散函数（PSF）的中心位于探测器视场（FOV）内和外。 我们将PSF位于FOV外的位置数据叠加，以获得均匀照明的矩阵，并使用专用的数据处理管道对所有数据集进行了降噪处理。 我们通过优化的数据处理方法确定了MXT的最佳光谱性能，特别是针对能量校准以及像素低能阈值引起的电荷共享效应。 我们的结果表明，MXT符合关于能量分辨率（1.5 keV时小于80 eV）、低能和高能阈值以及能量校准精度（$\pm$20 eV）的仪器要求。 我们还确定了探测器的电荷转移效率（~$10^{-5}$），并在MXT在轨寿命期间将经历的辐照之前对其随能量的变化进行了建模。 最后，我们测量了能量分辨率与光子能量的关系。 我们确定了MXT探测链的等效噪声电荷为4.9$\pm$0.2 e- rms，以及在208 K时硅中的Fano因子为0.131$\pm$0.003，这与之前的研究结果一致。 这次测试确认了MXT在任务期间能够提供的有前景的科学性能。 显示英文摘要

摘要： The Microchannel X-ray Telescope (MXT) is an innovative compact X-ray instrument on board the SVOM astronomical mission dedicated to the study of transient phenomena such as gamma-ray bursts. During 3 weeks, we have tested the MXT flight model at the Panter X-ray test facility under the nominal temperature and vacuum conditions that MXT will undergo in-flight. We collected data at series of characteristic energies probing the entire MXT energy range, from 0.28 keV up to 9 keV, for multiple source positions with the center of the point spread function (PSF) inside and outside the detector field of view (FOV). We stacked the data of the positions with the PSF outside the FOV to obtain a uniformly illuminated matrix and reduced all data sets using a dedicated pipeline. We determined the best spectral performance of MXT using an optimized data processing, especially for the energy calibration and the charge sharing effect induced by the pixel low energy thresholding. Our results demonstrate that MXT is compliant with the instrument requirement regarding the energy resolution (<80 eV at 1.5 keV), the low and high energy threshold, and the accuracy of the energy calibration ($\pm$20 eV). We also determined the charge transfer inefficiency (~$10^{-5}$) of the detector and modeled its evolution with energy prior to the irradiation that MXT will undergo during its in-orbit lifetime. Finally, we measured the relation of the energy resolution as function of the photon energy. We determined an equivalent noise charge of 4.9 $\pm$ 0.2 e- rms for the MXT detection chain and a Fano factor of 0.131 $\pm$ 0.003 in silicon at 208 K, in agreement with previous works. This campaign confirmed the promising scientific performance that MXT will be able to deliver during the mission lifetime.