Overview of MIRI instrument components
The JWST Mid-Infrared Instrument (MIRI) provides four observing modes from 5 to 28.5 μm. The major pieces of instrumentation hardware necessary to support these modes include the components listed below:
- Optics and focal plane—the imager (MIRIM) and medium resolution spectrometer (MRS) are fed from a single pick-off mirror (POM).
- Filters—there are 10 filters for imaging, four filter-diaphragm combinations for coronagraphy, one neutral density filter, one ZnS-Ge double prism for the LRS mode, one opaque position for darks, and one for a lens used during ground tests.
- Coronagraph masks—one occulter is based on the classic Lyot design and there are three occulters that incorporate 4-quadrant phase masks (4QPMs).
- Spectroscopic elements—a double prism is used for the low-resolution spectrometer and there are two dichroic filter combination wheels for the medium-resolution spectrometer.
- Detectors are three impurity band conduction (Si:As IBC) devices.
- Integral field units (IFUs)—there are four IFUs for the medium resolution spectrometer.