Gaia Data Release 1 On-orbit performance of the Gaia CCDs at L2
Gaia Data Release 1 On-orbit performance of the Gaia CCDs at L2
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Gaia 数据版本 1 L2 的 Gaia CCD 在轨性能
DOI：
10.1051/0004-6361/201628990
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发表时间：
2016
影响因子：
6.5
通讯作者：
Crowley C
中科院分区：
文献类型：
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作者：
Crowley C
欧洲航天局的盖亚卫星于2013年12月发射进入L2轨道，其有效载荷包含106个大型科学ccd。该任务的主要目标是在五年的时间里反复获得10亿颗恒星的高精度天文测量和光度测量。下行链路数据的科学价值，以及机载自主检测链的运行，都依赖于探测器的高性能。当卫星缓慢旋转并扫描天空时，ccd在线路时钟速率和卫星旋转自旋速率同步的模式下连续工作。名义任务操作于2014年7月开始，第一次数据发布正在准备中，将于2016年夏末发布。在本文中，我们概述了焦平面，探测器系统，以及系统的在轨性能监测策略。然后介绍性能结果，这是基于对从有效载荷开启开始的两年窗口期间获得的数据的分析。给出了读出噪声和电子偏移行为等参数的结果，并特别关注了L2辐射环境对器件的影响。清晰地诊断出（平行）扫描方向上辐射引起的电荷转移效率（CTE）下降；然而，外推表明，任务结束时的电荷转移效率低下（CTI）效应将比飞行前预测的低一个数量级。结果表明，串行寄存器（水平方向）中的CTI仍然由制造过程中固有的陷阱主导，并且迄今为止辐射引起的退化仅占百分之几。我们还介绍了电离辐射损伤和热像素演化跟踪的结果。最后，我们总结了一些在轨道上发现的仍在研究中的探测器效应。
The European Space Agency’sGaiasatellite was launched into orbit around L2 in December 2013 with a payload containing 106 large-format scientific CCDs. The primary goal of the mission is to repeatedly obtain high-precision astrometric and photometric measurements of one thousand million stars over the course of five years. The scientific value of the down-linked data, and the operation of the onboard autonomous detection chain, relies on the high performance of the detectors. AsGaiaslowly rotates and scans the sky, the CCDs are continuously operated in a mode where the line clock rate and the satellite rotation spin-rate are in synchronisation. Nominal mission operations began in July 2014 and the first data release is being prepared for release at the end of Summer 2016. In this paper we present an overview of the focal plane, the detector system, and strategies for on-orbit performance monitoring of the system. This is followed by a presentation of the performance results based on analysis of data acquired during a two-year window beginning at payload switch-on. Results for parameters such as readout noise and electronic offset behaviour are presented and we pay particular attention to the effects of the L2 radiation environment on the devices. The radiation-induced degradation in the charge transfer efficiency (CTE) in the (parallel) scan direction is clearly diagnosed; however, an extrapolation shows that charge transfer inefficiency (CTI) effects at end of mission will be approximately an order of magnitude less than predicted pre-flight. It is shown that the CTI in the serial register (horizontal direction) is still dominated by the traps inherent to the manufacturing process and that the radiation-induced degradation so far is only a few per cent. We also present results on the tracking of ionising radiation damage and hot pixel evolution. Finally, we summarise some of the detector effects discovered on-orbit which are still being investigated.