Charge-coupled device (CCD)-based technologies exposed to high-energy radiation are susceptible to the formation of stable defects within the charge transfer channel that defer signal to subsequent pixels and limit the lifetime of the detector. Performance degradation due to these defects depends upon the interplay between the clock timings used to operate the device and the properties of defects introduced by irradiation. Characterization of both the type and number of post-irradiation defects makes it possible to minimize charge loss though the appropriate selection of clock timings for a given operating temperature. This technique has the potential to increase nominal mission lifetimes by several years for CCD-based instruments and is of particular significance to electron multiplying charge-coupled devices (EMCCDs) for photon counting applications where the effect of charge traps on low signal levels is expected to be most severe. We present a study of charge traps within CCDs, specifically within EMCCDs irradiated at room temperature to proton fluences up to and including 1.45 × 1010 p + / cm2 (74 MeV). Defects are characterized through the “single-trap pumping” technique, with clocking schemes specifically designed for the 2-phase pixel architecture of the EMCCD. Five dominant trap species are thought to be introduced by the irradiation, the Si-E center, Si-A center, double and single acceptor charge states of the silicon divacancy (VV − − , VV − ), and an as yet unidentified defect referred to here as the Si-U center (the “unknown” trap). Energy-level and cross-section values are presented that allow inference of the defect landscape for a range of proton fluences and operating temperatures. While the study focuses specifically on EMCCDs, in more general terms, the results for trap properties are interpreted as being applicable to all CCD types following irradiation and can serve as a foundation for future charge loss correction and optimization techniques.

中文翻译：

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电子倍增电荷耦合器件中质子诱导的陷阱

暴露于高能量辐射下的基于电荷耦合器件（CCD）的技术易于在电荷传输通道中形成稳定的缺陷，这些缺陷会将信号延迟到后续像素，并限制了检测器的使用寿命。由于这些缺陷而导致的性能下降取决于用于操作该器件的时钟时序与辐射所引入的缺陷的性质之间的相互作用。的类型和辐照后的缺陷数量的表征使得能够最小化虽然时钟定时对于给定的操作温度下适当的选择电荷损失。这种技术有可能使基于CCD的仪器的标称任务寿命增加数年，并且对于光子计数应用中的电子倍增电荷耦合器件（EMCCD）尤其重要，在这种应用中，电荷陷阱对低信号电平的影响有望达到最严重。我们目前对CCD中的电荷陷阱进行研究，特别是在室温下辐照至质子通量达到和包括1.45×1010 p + / cm2（74 MeV）的EMCD中的电荷陷阱。缺陷通过“单阱泵浦”技术进行表征，并采用专门为EMCCD的2相像素架构设计的时钟方案。认为通过辐照会引入五种主要的陷阱种类：Si-E中心，Si-A中心，硅空位（VV--，VV-）的双受主和单受主电荷态，还有一个尚未确定的缺陷，这里称为Si-U中心（“未知”陷阱）。给出了能级和横截面值，可以推断出一系列质子通量和工作温度下的缺陷态势。尽管该研究专门针对EMCCD，但从更笼统的意义上讲，陷阱性质的结果被解释为适用于辐照后的所有CCD类型，并可作为将来电荷损耗校正和优化技术的基础。