Calibration of VELC detectors on-board Aditya-L1 mission

• Published in: arXiv.org
• Main Authors: Mishra, Shalabh, K Sasikumar Raja, Sanal Krishnan V U, Narra, Venkata Suresh, Bhavana Hegde S, Utkarsha, D, Muthu, Priyal V, Pawan, Kumar S, Natarajan, V, Raghavendra, Prasad B, Singh, Jagdev, Umesh, Kamath P, Kathiravan, S, Vishnu, T, Suresha, Savarimuthu, P, Desai, Jalshri H, Kumaran, Rajiv, Sagar, Shiv, Kumar, Sumit, Inderjeet Singh Bamrah, Kumar, Amit
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 12.03.2024
• Subjects: Calibration; Channels; Coronagraphs; Detectors; Payloads; Physics - Instrumentation and Methods for Astrophysics; Physics - Solar and Stellar Astrophysics; Sensors; Solar atmosphere; Space missions
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2403.07373

Aditya-L1 is the first Indian space mission to explore the Sun and solar atmosphere with seven multi-wavelength payloads, with Visible Emission Line Coronagraph (VELC) being the prime payload. It is an internally occulted coronagraph with four channels to image the Sun at 5000 \AA~ in the field of view 1.05 - 3 \rsun, and to pursue spectroscopy at 5303 \AA, 7892 \AA~ and 10747 \AA~ channels in the FOV (1.05 - 1.5 \rsun). In addition, spectropolarimetry is planned at 10747 \AA~ channel. Therefore, VELC has three sCMOS detectors and one InGaAs detector. In this article, we aim to describe the technical details and specifications of the detectors achieved by way of thermo-vacuum calibration at the CREST campus of the Indian Institute of Astrophysics, Bangalore, India. Furthermore, we report the estimated conversion gain, full-well capacity, and readout noise at different temperatures. Based on the numbers, it is thus concluded that it is essential to operate the sCMOS detectors and InGaAs detectors at \(-5^{\circ}\) and \(-17^{\circ}\) C, respectively, at the spacecraft level.