August 23, 2016

Mirim Instrument

MIRIM, The imager of MIRI



The imager is designed to work at 6K in 3 main modes:

  • the imaging mode that requires to filter the light according to the wavelength,
  • the coronagraphic mode that requires masks in the focal plane and in the pupil plane,
  • the stereoscopic mode that requires a slit in the focal plane and a dispersive element.

Filters WheelThe imager is mainly composed of the following elements:

  • the structure that holds all others elements,
  • the filter wheel with filters and pupil masks (for coronagraphy), a cryo-mechanism for rotation and a ratchet to fix its position,
  • the focal plane masks (for coronagraphy),
  • 2 mirrors for collimation and 3 mirrors for the Three Mirror Anastigmatic (TMA) objective that conduct the light to the detectors.

The coronagraphic mode uses 1 classical Lyot mask which operates at 23 µm wavelength and 3 Four Quadrant Phases masks (4QPM) which operates at 10.6 µm, 11.4 µm and 15.5 µm.

MIRIM coronographs
The MIRIM coronographs

The field of view corresponds to approximately 2.5 arcmin² on the sky.