Customer: IAC (Instituto de Astrofísica de Canarias).
The test cryostat will allow to perform the different test sets of the HARMONI Pre-Optics subsystem which will be part of an integral field spectrograph for the European Large Telescope (ELT) and It is an installation to test pre-optics in the infrared range of the electromagnetic spectrum thus it needs to keep cryogenic temperatures. The POTC (Pre-Optics Test Cryostat) will consists of different sub-systems all of them necessary to ensure the function of cooling the pre-optic in order to be tested. The different sub-systems will be the cryostat (130K), vacuum subsystem, cooling sub-system.
Operational vacuum: The cryostat shall provide the infrastructure to evacuate the air within the vacuum vessel to a pressure of 10-6 mbar cold and 10-5 mbar warm and the maximum allowable leak rate of the cryostat is less than 1 x 10-9 mbar l/s.
The cryostat is fitted with an overpressure release valve which shall limit the internal pressure to ≤ 1.2 bars.