Mitigating Charge Transfer Inefficiency in the Chandra X-Ray Observatory Advanced CCD Imaging Spectrometer
Mitigating Charge Transfer Inefficiency in the Chandra X-Ray Observatory Advanced CCD Imaging Spectrometer
复制标题
缓解钱德拉 X 射线天文台先进 CCD 成像光谱仪中电荷转移效率低下的问题
DOI：
10.1086/312672
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
J. Nousek
中科院分区：
文献类型：
--
作者：
L. Townsley;P. Broos;G. Garmire;J. Nousek
The ACIS front-illuminated CCDs on board the Chandra X-Ray Observatory were damaged in the extreme environment of the Earth's radiation belts, resulting in enhanced charge transfer inefficiency (CTI). This produces a row dependence in gain, event grade, and energy resolution. We model the CTI as a function of input photon energy, including the effects of detrapping (charge trailing), shielding within an event (charge in the leading pixels of the 3 × 3 event island protects the rest of the island by filling traps), and nonuniform spatial distribution of traps. This technique cannot fully recover the degraded energy resolution, but it reduces the position dependence of gain and grade distributions. By correcting the grade distributions as well as the event amplitudes, we can improve the instrument's quantum efficiency. We outline our model for CTI correction and discuss how the corrector can improve astrophysical results derived from ACIS data.
