Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published March 5, 2003 | Published
Book Section - Chapter Open

Planck-HFI thermal architecture: from requirements to solutions

Abstract

The Planck-High Frequency Instrument (HFI) will use 48 bolometers cooled to 100mK by a dilution cooler to map the Cosmic Microwave Background (CMB) with a sensitivity of ΔT/T~2.10^(-6) and an angular resolution of 5 minutes of arc. This instrument will therefore be about 1000 times more sensitive than the COBE-DMR experiment. This contribution will focus mainly on the thermal architecture of this instrument and its consequences on the fundamental and instrumental fluctuations of the photon flux produced on the detectors by the instrument itself. In a first step, we will demonstrate that the thermal and optical design of the HFI allow to reach the ultimate sensitivity set by photon noise of the CMB at millimeter wavelength. Nevertheless, to reach such high sensitivity, the thermal behavior of each cryogenic stages should also be controlled in order to damp thermal fluctuations that can be taken as astrophysical signal. The requirement in thermal fluctuation on each stage has been defined in the frequency domain to degrade the overall sensitivity by less than 5%. This leads to unprecedented stability specifications that should be achieved down to 16mHz. We will present the design of the HFI thermal architecture, based on active and passive damping, and show how its performances were improved thanks to thermal simulations.

Additional Information

© 2003 Society of Photo-optical Instrumentation Engineers (SPIE).

Attached Files

Published - 740.pdf

Files

740.pdf
Files (610.5 kB)
Name Size Download all
md5:9a8167c6c685bfd3bf8691fe8e9ec9cc
610.5 kB Preview Download

Additional details

Created:
August 19, 2023
Modified:
January 14, 2024