Mid-Infrared Instrument

[1] MIRI is a camera and a spectrograph that observes mid to long infrared radiation from 5 to 28 microns.

[1] Because it views the longer wavelengths it needs to be cooler than the other instruments (see Infrared astronomy), and it has an additional cooling system.

[1] The cooling system for MIRI includes a pulse tube precooler and a Joule-Thomson loop heat exchanger.

[1] MIRI was built by the MIRI Consortium, a group that consists of scientists and engineers from 10 different European countries (the United Kingdom, France, Belgium, the Netherlands, Germany, Spain, Switzerland, Sweden, Denmark, and Ireland) with the United Kingdom heading the European consortium,[3] as well as a team from the Jet Propulsion Lab in California, and scientists from several U.S.

[4] The spectrograph can observe wavelengths between 4.6 and 28.6 microns, and it has four separate channels, each with its own gratings and image slicers.

[1] The detectors (one for the imager, and two for the spectrometer) each have a resolution of 1024x1024 pixels, and they are called Focal Plane Modules or FPMs.

[10] The imager module of MIRI also includes the Low Resolution Spectrometer that can perform long-slit and slitless spectroscopy from 5 to 12 μm light wavelength.

[11] The LRS uses Ge (germanium) and ZnS (zinc sulfide) prisms to cause spectroscopic dispersion.

[11] Commissioning is complete as of the following dates: To allow mid-infrared observations within the JWST, the MIRI instrument has an additional cooling system.

In this case the JWST cryocooler resides in the spacecraft bus and it has lines of coolant that run to the MIRI instrument, chilling it.