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- The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spectrometer
contains nine germanium detectors that are positioned behind the nine grid
pairs on the telescope. These artificially grown crystals, pure to over one
part in a trillion, were manufactured by the ORTEC division of PerkinElmer
Instruments. When they are cooled to cryogenic temperatures and a high voltage
is put across them (up to 4000 V), they convert incoming x-rays and gamma-rays
to pulses of electric current. The amount of current is proportional to the
energy of the photon, and is measured by sensitive electronics designed at the
Lawrence Berkeley National Laboratory and the Space Sciences Lab., Berkeley.
The detectors are cooled with a recently developed electromechanical cryocooler
(built by Sunpower, Inc. and flight qualified at Goddard. It maintains them at
the required operating temperature of minus 324 degrees Fahrenheit (minus 198
degrees Centigrade, or 75 degrees above absolute zero).
For more information, see:
http://hesperia.gsfc.nasa.gov/hessi/instrumentation.htm
Group: Instrument_Details
Entry_ID: HESSI SPECTROMETER
Group: Instrument_Identification
Instrument_Category: Solar/Space Observing Instruments
Instrument_Class: X-Ray/Gamma Ray Detectors
Short_Name: HESSI SPECTROMETER
End_Group
Group: Associated_Platforms
Short_Name: RHESSI
End_Group
Group: Spectral_Frequency_Information
Wavelength_Keyword: X-Ray
Number_Channels: 1
End_Group
Online_Resource: http://hesperia.gsfc.nasa.gov/hessi/hessispec.htm
Sample_Image: http://hesperia.gsfc.nasa.gov/hessi/images/detectors.jpg
Group: Instrument_Logistics
Instrument_Start_Date: 2002-02-05
Instrument_Owner: NASA/GSFC
End_Group
End_Group
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