Project Title:

A Cryogenic Absolute Radiometer for Earth Radiation Sensing

08.04-2627
A Cryogenic Absolute Radiometer for Earth Radiation Sensing
Cambridge Research And Instrumentation, Inc.
21 Erie Street
Cambridge
MA
02139
Foukal
Peter V.
617-491-2627
50319
18223
50,000
LaRC

Abstract:

The purpose of this project is to develop a helium-cooled absolute radiometer suitable
for wide-band measurements of the Earth's radiation at an angular resolution two
orders of magnitude better than achieved with the existing ERBE radiometers.  We
have constructed and characterized a helium-cooled radiometer over the past four
years.  This sucessful instrument is optimized for laboratory standards applications
and is presently being used for studies of photodiode yield under laser illumination.
 The aim of this Phase I study is to design and construct an ultra low-mass receiver
for this radiometer and test its performance against a numerical heat flow model.
 This comparison will enable us to determine whether the dramatic advantages in sensitivity
and time constant that a helium-cooled radiometer seems to offer in such a measurement
can be realized in practice.  If the Phase I results are favorable, we will request
Phase II support to construct a prototype helium-cooled radiometer optimized for
Earth radiation measurements from the Shuttle and the Space Station.