Share Email Print
cover

Proceedings Paper • new

Snowballs in Euclid and WFIRST detectors
Author(s): Analia N. Cillis; David A. Cottingham; Augustyn Waczynski; Robert J. Hill; Yiting Wen; Roger Foltz; Edward Cheng; Stephanie A. Cheung; Benjamin Cho; Gregory S. Delo; Ali R. Feizi; Michael Hickey; Tsuwei Hwang; Emily Kan; Eric Kan; Wayne B. Landsman; Jonathan S. Mah; Lane A. Meier; Chris Merchant; Laddawan Miko; Jhabvala D. Murzy; Dino Rossetti; Kyle A. Turck
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Snowballs are transient events observed in HgCdTe detectors with a sudden increase of charge in a few pixels. They appear between consecutive reads of the detector, after which the affected pixels return to their normal behavior. The origin of the snowballs is unknown, but it was speculated that they could be the result of alpha decay of naturally radioactive contaminants in the detectors, but a cosmic ray origin cannot be ruled out. Even though previous studies predicted a low rate of occurrence of these events, and consequently, a minimal impact on science, it is interesting to investigate the cause or causes that may generate snowballs and their impact in detectors designed for future missions. We searched for the presence of snowballs in the dark current data in Euclid and Wide Field Infrared Survey Telescope (WFIRST) detectors tested in the Detector Characterization Laboratory at Goddard Space Flight Center. Our investigation shows that for Euclid and WFIRST detectors, there are snowballs that appear only one time, and others than repeat in the same spatial localization. For Euclid detectors, there is a correlation between the snowballs that repeat and bad pixels in the operational masks (pixels that do not fulfill the requirements to pass spectroscopy, photometry noise, quantum efficiency, and/or linearity). The rate of occurrence for a snowball event is about 0.9 snowballs/hr. in Euclid detectors (for the ones that do not have associated bad pixels in the mask), and about 0.7 snowballs/hr. in PV3 Full Array Lot WFIRST detectors.

Paper Details

Date Published: 6 July 2018
PDF: 16 pages
Proc. SPIE 10698, Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave, 106983A (6 July 2018); doi: 10.1117/12.2312666
Show Author Affiliations
Analia N. Cillis, Univ. of Maryland, Balitmore County, NASA Goddard Space Flight Ctr. (United States)
David A. Cottingham, Conceptual Analytics (United States)
Augustyn Waczynski, NASA Goddard Space Flight Ctr. (United States)
Robert J. Hill, Conceptual Analytics (United States)
Yiting Wen, NASA Goddard Space Flight Ctr. (United States)
Roger Foltz, NASA Goddard Space Flight Ctr. (United States)
Edward Cheng, Conceptual Analytics (United States)
Stephanie A. Cheung, AS and D, Inc. (United States)
Benjamin Cho, AS and D, Inc. (United States)
Gregory S. Delo, AS and D, Inc. (United States)
Ali R. Feizi, AK Aerospace Technology Corp. (United States)
Michael Hickey, NASA Goddard Space Flight Ctr. (United States)
Tsuwei Hwang, AS and D, Inc. (United States)
Emily Kan, NASA Goddard Space Flight Ctr. (United States)
Eric Kan, NASA Goddard Space Flight Ctr. (United States)
Wayne B. Landsman, ADNET Systems, Inc. (United States)
Jonathan S. Mah, Conceptual Analytics (United States)
Lane A. Meier, Conceptual Analytics (United States)
Chris Merchant, Global Science & Technology, Inc. (United States)
Laddawan Miko, NASA Goddard Space Flight Ctr. (United States)
Jhabvala D. Murzy, NASA Goddard Space Flight Ctr. (United States)
Dino Rossetti, Conceptual Analytics (United States)
Kyle A. Turck, Global Science & Technology, Inc. (United States)


Published in SPIE Proceedings Vol. 10698:
Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave
Makenzie Lystrup; Howard A. MacEwen; Giovanni G. Fazio; Natalie Batalha; Nicholas Siegler; Edward C. Tong, Editor(s)

© SPIE. Terms of Use
Back to Top