Design for the COBE far-infrared absolute spectrophotometer (FIRAS)

John C. Mather; Dale J. Fixsen; Richard A. Shafer

doi:10.1117/12.157823

1 October 1993 Design for the COBE far-infrared absolute spectrophotometer

John C. Mather, Dale J. Fixsen, Richard A. Shafer

Proceedings Volume 2019, Infrared Spaceborne Remote Sensing; (1993) https://doi.org/10.1117/12.157823
Event: SPIE's 1993 International Symposium on Optics, Imaging, and Instrumentation, 1993, San Diego, CA, United States

Abstract

The Far InfraRed Absolute Spectrophotometer (FIRAS) was built to measure the spectrum of diffuse emission from 1 to 100 cm^-1, with particular attention to possible differences between the spectrum of the cosmic microwave background radiation (CMBR) and a blackbody spectrum as small as 0.1% of the peak of the CMBR spectrum. The FIRAS has differential inputs and outputs, a full beam external calibrator, a controllable reference blackbody, and a polarizing Michelson interferometer with bolometer detectors. It is operated at a temperature of 1.5 K inside a liquid helium cryostat to suppress instrument emission and improve detector sensitivities. It has an intrinsic frequency resolution of the order of 0.7%, maximum path lengths of 1.2 and 5.9 cm, and a beamwidth of 7 degree(s), and achieved its goals for accuracy and rms sensitivity for νI_ν, which are better than 10^-9 W/cm²sr over the frequency range from 2 to 20 cm^-1.

Citation Download Citation

John C. Mather, Dale J. Fixsen, and Richard A. Shafer "Design for the COBE far-infrared absolute spectrophotometer", Proc. SPIE 2019, Infrared Spaceborne Remote Sensing, (1 October 1993); https://doi.org/10.1117/12.157823

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available