Design of the holding system for an infrared detector

The near-infrared detector that will be mounted on MAJIS ( Moons And Jupiter Imaging Spectrometer) covers a wavelength range from 1.5 to 5.1 μm with an operating temperature lower than 90 K. This cryogenic temperature with a combination of a proper thermal design of the instrument cooling system in combination of the design of the mechanical holding system. The thermo-mechanical design of the detector holding system, has been developed with FE models and numerical analyses. The design rationale is based on a compliant structure made of titanium and aluminum to reduce the thermo-elastic stresses on the detector while simultaneously maintain its thermal insulating from the warm optical bench in the expected cryogenic environment. The holding system is also required to have sufficient stiffness to reach natural frequencies above 150 Hz to maintain the safety of the instrument during launching, and to overcome a quasi-static loading of 350 m/s2. These requirements lead to a trade-off solution between the insulation and mechanical resistance needs. Feasibility design of an aluminum-foil based thermal strap has been validated as well, in order to meet the mass, conductivity and flexibility requirements need for removing dissipated heat from the sensitive IR detector.