The MIllimeter Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs (MISTRAL) is a new cryogenic W-band LEKID camera that was successfully installed at the Gregorian focus of the 64 m fully steerable Sardinia Radio Telescope (SRT) in Italy during May 2023. MISTRAL was developed in the framework of the SRT-HighFreq project, funded by a National Operational Program (PON), with the aim to expand the capabilities of the radio telescope to cover frequencies up to the W band. The instrument is designed to have key performance features: a 12 arcsecond angular resolution, a 4 arcminute instantaneous field of view, and high sensitivity. The scientific potential of MISTRAL is vast, aiming to study different research areas in modern astrophysics. Its high resolution and sensitivity are uniquely suited to observe galaxy clusters contributing to the search for the ’missing baryon’ problem by observing the faint thermal Sunyaev-Zel’dovich effect. Furthermore, MISTRAL can also contribute in studies across both extragalactic and galactic astrophysics, probing everything from large scale structures in the universe to galactic science and solar system science. To guarantee the proper functioning of this instrument, the commissioning phase was crucial and presented unique technical challenges. These observations are the first W-band measurements conducted at the SRT, consequently the first with such high angular resolution. Previous receiver setups and look-up tables, optimized for lower frequencies and consequently lower angular resolutions, were found to be inadequate for an instrument as resolute as MISTRAL. The requirement for a diffraction-limited beam required a fine-tuning of the telescope’s optical system. Therefore, this contribution provides a comprehensive and detailed overview of such fine tuning as part of the technical commissioning process. We specifically present the optical alignment procedures executed to optimize the SRT’s primary and secondary mirror system and detail the subsequent beam optimization analysis performed to ensure optimal and high-resolution performance of MISTRAL.
MISTRAL: optical alignment and beam optimization at the Sardinia Radio Telescope / Barbavara, E., Attoli, A., Battistelli, E.S., Bellucci, C., De Bernardis, P., Cacciotti, F., Carboni, G., Carretti, E., Ciccalotti, D., Columbro, F., Coppolecchia, A., Cruciani, A., D'Alessandro, G., De Gasperis, G., De Petris, M., Ferazzoli, S., Govoni, F., Isopi, G., Ladu, A., Lamagna, L., et al.. - (2026). (SPIE Astronomical Telescopes + Instrumentation 2026 Copenhagen, Denmark ) [10.1117/12.3103830].
MISTRAL: optical alignment and beam optimization at the Sardinia Radio Telescope
Eleonora Barbavara;Elia Stefano Battistelli;Costanza Bellucci;Paolo de Bernardis;Federico Cacciotti;Daniele Ciccalotti;Fabio Columbro;Alessandro Coppolecchia;Angelo Cruciani;Giuseppe D'Alessandro;Giancarlo De Gasperis;Marco De Petris;Sofia Ferazzoli;Giovanni Isopi;Luca Lamagna;Davide Marsala;Silvia Masi;Matteo Murgia;Alessandro Novelli;Andrea Occhiuzzi;Alessandro Paiella;Giorgio Pettinari;Francesco Piacentini;Giampaolo Pisano;
2026
Abstract
The MIllimeter Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs (MISTRAL) is a new cryogenic W-band LEKID camera that was successfully installed at the Gregorian focus of the 64 m fully steerable Sardinia Radio Telescope (SRT) in Italy during May 2023. MISTRAL was developed in the framework of the SRT-HighFreq project, funded by a National Operational Program (PON), with the aim to expand the capabilities of the radio telescope to cover frequencies up to the W band. The instrument is designed to have key performance features: a 12 arcsecond angular resolution, a 4 arcminute instantaneous field of view, and high sensitivity. The scientific potential of MISTRAL is vast, aiming to study different research areas in modern astrophysics. Its high resolution and sensitivity are uniquely suited to observe galaxy clusters contributing to the search for the ’missing baryon’ problem by observing the faint thermal Sunyaev-Zel’dovich effect. Furthermore, MISTRAL can also contribute in studies across both extragalactic and galactic astrophysics, probing everything from large scale structures in the universe to galactic science and solar system science. To guarantee the proper functioning of this instrument, the commissioning phase was crucial and presented unique technical challenges. These observations are the first W-band measurements conducted at the SRT, consequently the first with such high angular resolution. Previous receiver setups and look-up tables, optimized for lower frequencies and consequently lower angular resolutions, were found to be inadequate for an instrument as resolute as MISTRAL. The requirement for a diffraction-limited beam required a fine-tuning of the telescope’s optical system. Therefore, this contribution provides a comprehensive and detailed overview of such fine tuning as part of the technical commissioning process. We specifically present the optical alignment procedures executed to optimize the SRT’s primary and secondary mirror system and detail the subsequent beam optimization analysis performed to ensure optimal and high-resolution performance of MISTRAL.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
