The Soft X-ray Spectrometer on Hitomi
This photo shows the Soft X-ray Spectrometer (SXS) on the Hitomi satellite, which is enclosed within a sophisticated cooling system, designed to keep its sensor at a temperature of 50 mK.
The SXS is a high-resolution, high-throughput spectrometer sensitive to photons with energy between 0.3 keV and 12 keV. It is a non-dispersive spectrometer, based on a calorimeter rather than on a grating, and therefore can achieve a spectral resolution of less than 7 eV – this is much higher than what is accessible to current grating spectrometers.
The instrument also has a filter wheel, developed by the Netherlands Institute for Space Research (SRON) and the University of Geneva, to prevent strong X-ray sources from saturating the spectrometer, so that it can make accurate observations of a large range of astrophysical sources.
Hitomi (known as ASTRO-H prior to launch) is a high-energy astrophysics space observatory, developed by the Japan Aerospace Exploration Agency (JAXA) in collaboration with institutions in Japan, the US, Canada, and Europe.