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The 0.1K bolometers cooled by adiabatic demagnetizationThe most straightforward way of reducing the noise equivalent power of bolometers is to lower their operating temperature. We have been exploring the possibility of using conventionally constructed bolometers at ultra-low temperatures to achieve NEP's suitable to the background environment of cooled space telescopes. We have chosen the technique of adiabatic demagnetization of a paramagnetic salt as a gravity independent, compact, and low power way to achieve temperatures below pumped He-3 (0.3 K). The demagnetization cryostat we used was capable of reaching temperatures below 0.08 K using Chromium Potassium Alum as a salt from a starting temperature of 1.5 K and a starting magnetic field of 30,000 gauss. Computer control of the magnetic field decay allowed a temperature of 0.2 K to be maintained to within 0.5 mK over a time period exceeding 14 hours. The refrigerator duty cycle was over 90 percent at this temperature. The success of these tests has motivated us to construct a more compact portable adiabatic demagnetization cryostat capable of bolometer optical tests and use at the 5m Hale telescope at 1mm wavelengths.
Document ID
19930073194
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Roellig, T.
(NASA Ames Research Center Moffett Field, CA, United States)
Lesyna, L.
(NASA Ames Research Center Moffett Field, CA, United States)
Kittel, P.
(NASA Ames Research Center Moffett Field, CA, United States)
Werner, M.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 16, 2013
Publication Date
August 1, 1983
Publication Information
Publication: Infrared Detector Technology Workshop
Subject Category
Optics
Accession Number
93N70641
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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