Calibration of VELC detectors on-board Aditya-L1 mission

• Published in: Experimental astronomy 2024-04, Vol.57 (2), Article 7
• Main Authors: Mishra, Shalabh, K, Sasikumar Raja, VU, Sanal Krishnan, Narra, Venkata Suresh, S, Bhavana Hegde, D, Utkarsha, V, Muthu Priyal, S, Pawan Kumar, V, Natarajan, B, Raghavendra Prasad, Singh, Jagdev, P, Umesh Kamath, S, Kathiravan, T, Vishnu, Suresha, P, Savarimuthu, Desai, Jalshri H, Kumaran, Rajiv, Sagar, Shiv, Kumar, Sumit, Bamrah, Inderjeet Singh, Kumar, Amit
• Format: Article
• Language: English
• Subjects: Astronomy; Calibration; Channels; Chemistry and Earth Sciences; Computer Science; Coronagraphs; Detectors; Observations and Techniques; Payloads; Physics; Physics and Astronomy; Sensors; Solar atmosphere; Space missions; Statistics for Engineering
• ISSN: 0922-6435; 1572-9508
• DOI: 10.1007/s10686-024-09922-2

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 Å  in the field of view 1.05 - 3 R ⊙ , and to pursue spectroscopy at 5303 Å, 7892 Å  and 10747 Å  channels in the FOV (1.05 - 1.5 R ⊙ ). In addition, spectropolarimetry is planned at 10747 Å  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 detector at - 5 ∘ and - 17 ∘ C, respectively, at the spacecraft level.