Instrumentation and Technology for PRIMA: the PRobe far-Infrared Mission for Astrophysics

PRIMA's covers the 24 to 235 micron waveband with sensitivity limited only by the natural astrophysical backgrounds, a first for this waveband. PRIMA's observatory uses a staged thermal architecture featuring passive cooling to 45 K, along with active cooling at 4.5 K for the telescope, 1 K for the instruments, and 120 mK for the focal plane arrays. PRIMA's two instruments view the sky through a 1.8-meter all-aluminum telescope. The PRIMAger imaging instrument uses a linear variable filter for rapid multiband imaging of extragalactic fields from 24-84 microns, and simultaneous polarimetry in four bands spanning 90 to 235 microns. The spectrometer FIRESS can be used for both pointed spectroscopy and spectral mapping. FIRESS employs four all-aluminum grating modules, spaced logarithmically across the band to provide resolving power R greater than 100. FIRESS also provides higher resolving power (up to 4,500 at 112 microns) by processing the light incident on the grating spectrometers with a Fourier-transform module (FTM). This post-dispersed Fourier approach combines excellent line sensitivity with full-band coverage. At the heart of both PRIMA instruments are arrays of kinetic inductance detectors (KIDs), developed by the PRIMA team, including JPL, SRON, and GSFC. I will outline the rationale for KIDs among the landscape of potential detector options, our approach to the KIDs and their integration into the payload, and our progress in demonstrating PRIMA's required KID sensitivities and array formats.