标题： Gaia CCD在L2点运行30个月后的辐射效应 显示英文标题

标题： Radiation effects on the Gaia CCDs after 30 months at L2

摘要： 自2013年12月欧洲航天局的盖亚卫星发射以来，机载的106个大型科学CCD一直在L2点运行。 由于任务所需的高精度测量要求和L2点预测的质子环境，非电离辐射损伤对探测器的影响被提前识别为可能对数据的科学价值构成重大限制。 本文比较了飞行前辐射引起的电荷转移效率（CTI）预测与在轨测量结果，特别关注电荷注入诊断，并将这些CTI诊断结果与太阳质子事件数据相关联。 我们显示，自发射以来，面向L2的太阳活动相对较低，辐射损伤（到目前为止）低于最初预期。 尽管如此，地球定向的太阳日冕物质抛射事件与CTI诊断随时间变化的突然变化之间存在明显的相关性。 这些突然的变化叠加在一个相当稳定的CTI增加之上，我们证明这主要是由于设备持续受到高能银河宇宙射线的轰击。 我们检查了CTI低于预期水平的可能原因，以及控制有效载荷加热事件对CTI诊断的影响。 CCD串行寄存器中的辐射引起的CTI以及电离辐射的影响也低于预期，然而这些主题在这里没有详细探讨。 显示英文摘要

摘要： Since the launch of ESA's Gaia satellite in December 2013, the 106 large-format scientific CCDs onboard have been operating at L2. Due to a combination of the high-precision measurement requirements of the mission and the predicted proton environment at L2, the effect of non-ionizing radiation damage on the detectors was early identified pre-launch as potentially imposing a major limitation on the scientific value of the data. In this paper we compare pre-flight radiation-induced Charge Transfer Inefficiency (CTI) predictions against in-flight measurements, focusing especially on charge injection diagnostics, as well as correlating these CTI diagnostic results with solar proton event data. We show that L2-directed solar activity has been relatively low since launch, and radiation damage (so far) is less than originally expected. Despite this, there are clear cases of correlation between earth-directed solar coronal mass ejection events and abrupt changes in CTI diagnostics over time. These sudden jumps are lying on top of a rather constant increase in CTI which we show is primarily due to the continuous bombardment of the devices by high-energy Galactic Cosmic Rays. We examine the possible reasons for the lower than expected levels of CTI as well as examining the effect of controlled payload heating events on the CTI diagnostics. Radiation-induced CTI in the CCD serial registers and effects of ionizing radiation are also correspondingly lower than expected, however these topics are not examined here in detail.