Abstract
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 \(\varvec{R}_{\odot }\), and to pursue spectroscopy at 5303 Å, 7892 Å and 10747 Å channels in the FOV (1.05 - 1.5 \(\varvec{R}_{\odot }\)). 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 \(\varvec{-5^\circ }\) and \(\varvec{-17^{\circ }}\) C, respectively, at the spacecraft level.
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Acknowledgements
We thank all the Scientists/Engineers at the various centres of ISRO such as URSC, SAC, LEOS, VSSC etc. and Indian Institute of Astrophysics who have made great contributions to the mission in order to achieve the present state. We thank anonymous referee for providing valuable suggestions that improved the manuscript.
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We gratefully acknowledge the financial support from Indian Space Research Organization (ISRO), India for this project.
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SM and KSR analysed the data and wrote the manuscript. SM, KSR, SKVU, BH, UD involved in calibration activities and acquiring the data. BRP, JS, VSN, AK provided the inputs with the setup, designing calibration procedures etc and also reviewed the manuscript. MP and SP helped with the data analysis. PUK, PK, NV, KS, VT, Suresha extended their help with the ETF facility, mounting the detectors in the TVAC chamber, maintaining the pressure and temperatures at desired levels etc. JHD, RK, SS, SK, ISB are the designers of the hardware electronics related to the detectors.
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Mishra, S., K, S., VU, S. et al. Calibration of VELC detectors on-board Aditya-L1 mission. Exp Astron 57, 7 (2024). https://doi.org/10.1007/s10686-024-09922-2
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DOI: https://doi.org/10.1007/s10686-024-09922-2