Laboratory and In-Flight Measurements at 10–55 K of InSb Near-Infrared Detector Performance for the Warm Mission of theAKARISatellite

• Published in: Publications of the Astronomical Society of the Pacific 2011-08, Vol.123 (906), p.942-952
• Main Authors: Mori, Tatsuya, Kaneda, Hidehiro, Ishihara, Daisuke, Oyabu, Shinki, Wada, Takehiko
• Format: Article
• Language: eng ; jpn
• ISSN: 0004-6280; 1538-3873
• DOI: 10.1086/661664

The warm mission phase ofAKARI, the Japanese infrared astronomical satellite, has started after its 180 liter liquid helium cryogen was exhausted. Since then, we have conducted near-infrared observations with the Infrared Camera (IRC), while the telescope is slowly warming up. To explore the possibility of continuing observations at higher temperatures, we evaluate the performance of the InSb detector array, a flight backup model for the IRC, in a laboratory at various operating temperatures between 10 K and 55 K. By combining the laboratory measurements with the in-flight measurements of theAKARI/IRC detector array, we consistently derive the changes of relative sensitivity, dark current, total noise, and the number of hot pixels with operating temperature. All of them show small changes in a range of temperature from 10 K to 40 K. However, at temperatures above 40 K, the dark current and the number of hot pixels start to increase rapidly, while the relative sensitivity decreases and the total noise increases gradually. We obtain the dependence of the performance on bias voltages to suggest an optimal operation for a futureAKARIwarmer phase.