为XRISM卫星软X射线成像望远镜Xtend研制的CCD电荷转移效率的实验研究
Experimental studies on the charge transfer inefficiency of CCD developed for the soft X-ray imaging telescope Xtend aboard the XRISM satellite
摘要：
对XRISM卫星软X射线成像望远镜Xtend的电荷耦合器件（CCD）的电荷转移效率（CTI）进行了实验研究。CCD配备有电荷注入（CI）能力，其中周期性地注入牺牲电荷以填充电荷陷阱。通过计算在CI行后面观察到的陷阱电荷的再发射，我们发现至少有三个具有不同时间常数的陷阱种群。具有最短时间常数的陷阱（其等效于大约一个像素的转移时间）主要负责在下一像素中看到的X射线事件的拖尾电荷。在两种时钟模式下的拖尾电荷的比较表明，CTI不仅取决于传输时间，而且取决于面积，即成像或存储区域。我们建立了一个新的CTI模型，同时考虑到传输时间和面积的依赖性。该模型再现了在两种时钟模式下获得的数据一致。我们还研究了没有CI技术观察到的CTI的表观通量依赖性。入射X射线通量越高，CTI值越低。这是由于另一个X射线光子的牺牲电荷效应。当使用CI技术时，发现这种影响可以忽略不计。
英文摘要：
We present experimental studies on the charge transfer inefficiency (CTI) of charge-coupled device (CCD) developed for the soft X-ray imaging telescope, Xtend, aboard the XRISM satellite. The CCD is equipped with a charge injection (CI) capability, in which sacrificial charge is periodically injected to fill the charge traps. By evaluating the re-emission of the trapped charge observed behind the CI rows, we find that there are at least three trap populations with different time constants. The traps with the shortest time constant, which is equivalent to a transfer time of approximately one pixel, are mainly responsible for the trailing charge of an X-ray event seen in the following pixel. A comparison of the trailing charge in two clocking modes reveals that the CTI depends not only on the transfer time but also on the area, namely the imaging or storage area. We construct a new CTI model with taking into account with both transfer-time and area dependence. This model reproduces the data obtained in both clocking modes consistently. We also examine apparent flux dependence of the CTI observed without the CI technique. The higher incident X-ray flux is, the lower the CTI value becomes. It is due to a sacrificial charge effect by another X-ray photon. This effect is found to be negligible when the CI technique is used.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
