SPICA Far-IR Polarimeter: B-BOP

  • Polarization sensitive resistive bolometers in 3 bands: 110, 220, 350μm
  • FPA architecture designed/tested
  • Readout analogous to PACS system
  • Magnetic fields in dust filaments

The prime science driver for the far-IR imaging component of SPICA is the polarimetric mapping of Galactic filamentary structures, which requires a high dynamic range both in spatial scales and flux density. For high mapping efficiency a large instantaneous field of view, simultaneously in all wavelength bands is required, within the budget set by the satellite (thermal, electrical, mass, volume). This needs to be implemented using detectors offering high sensitivity at faint flux levels, but with a high immunity to high flux levels. The wavelength bands are defined by the need to observe filaments on both sides of their peak emission, suggesting bands centered around 100µm, 200µm, and 350µm. For efficient polarimetry, polarizing detectors are used. The required performance parameters of the instrument are summarized in the B-BOP fact sheet. The adopted detector sensitivity of 3×10-18W/√Hz can be achieved with detectors that were originally developed for an earlier incarnation of the B-Bop instrument. Modifying these detectors to polarization-sensitive pixels will not affect their noise performance.