Annealing bounds to prevent further Charge Transfer Inefficiency increase of the Chandra X-ray CCDs

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:389

Article

Monmeyran, Corentin¹  Patel, Neil S.¹  Bautz, Mark W.²  Grant, Catherine E.²  Prigozhin, Gregory Y.²  Agarwal, Anuradha³  Kimerling, Lionel C.^1,3 

[1] MIT, Dept Mat Sci & Engn, 77 Massachusetts Ave, Cambridge, MA 02139 USA

[2] MIT, Kavli Inst Astrophys & Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA

[3] MIT, Microphoton Ctr, 77 Massachusetts Ave, Cambridge, MA 02139 USA

关键词: Irradiation;    Point defect;    Chandra;    Charge Transfer Inefficiency;    CCD;    Proton;    Annealing;    Defect reaction;    Interstitial;    Carbon;   

DOI  :  10.1016/j.nimb.2016.11.020

来源: Elsevier

【 摘 要 】

After the front-illuminated CCDs on board the X-ray telescope Chandra were damaged by radiation after launch, it was decided to anneal them in an effort to remove the defects introduced by the irradiation. The annealing led to an unexpected increase of the Charge Transfer Inefficiency (CTI). The performance degradation is attributed to point defect interactions in the devices. Specifically, the annealing at 30 degrees C activated the diffusion of the main interstitial defect in the device, the carbon interstitial, which led to its association with a substitutional impurity, ultimately resulting in a stable and electrically active defect state. Because the formation reaction of this carbon interstitial and substitutional impurity associate is diffusion limited, we recommend a higher upper bound for the annealing temperature and duration of any future CCD anneals, that of -50 degrees C for one day or -60 degrees C for a week, to prevent further CTI increase. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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