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- The Transient Gamma-Ray Spectrometer (TGRS) on WIND will detect transient
gamma-ray burst events and will make the first high-resolution spectroscopic
survey of cosmic gamma-ray bursts, and will also make measurements of gamma-ray
lines in solar flares.
Cosmic gamma-ray bursts are among the most violent and energetic processes
known to exist in nature, characteristically emitting most of their luminosity
at gamma-ray wavelengths. The high-resolution spectroscopy of solar flares will
contribute to the study of solar flare activities and help in understanding the
coupling between the active corona and photosphere.
The TGRS instrument consists of four assemblies: detector cooler assembly,
pre-amp, and analog processing unit, all mounted on a tower on the +Z end of
the spacecraft, and a digital processing unit mounted in the body of the
spacecraft. The detector is a 215 cubic cm high purity n-type germanium crystal
of dimensions: 6.7 cm (diameter) X 6.1 cm (length), radiatively colled to 85
degrees K. The germanium serves as a reaction medium for incoming gamma rays,
which, depending on their energy, are either stopped by or passed through the
detector crystal. Particle energy and angle of incidence are calculated based
on a number of primary and secondary interaction processes, including
photoelectric, Compton, pair and bremsstrahlung radiation as well as the
ionization energy losses of secondary electrons. A two-stage cooler surrounds
the detector, providing a field of view of 170 degrees. Gamma-ray bursts and
solar flares are expected to be detected at a frequency of several per week,
with typical durations between 1 second and several minutes. Between bursts the
instrument is maintained in a waiting mode, measuring background counting rates
and energy spectra. When a burst or flare occurs, the instrument switches to a
burst mode, where each event in the detector is pulse-height analyzed and time
tagged in a burst memory. Then the instrument switches to a dump mode for
reading out the burst memory.
Group: Instrument_Details
Entry_ID: TGRS
Group: Instrument_Identification
Instrument_Category: Solar/Space Observing Instruments
Instrument_Class: X-Ray/Gamma Ray Detectors
Short_Name: TGRS
Long_Name: Transient Gamma-Ray Spectrometer
End_Group
Group: Associated_Platforms
Short_Name: WIND
End_Group
Group: Spectral_Frequency_Information
Wavelength_Keyword: Gamma Ray
Number_Channels: 1
Spectral_Frequency_Coverage_Range: 15 KeV - 10 MeV
End_Group
Online_Resource: http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1994-071A&ex=2
Online_Resource: http://www-spof.gsfc.nasa.gov/istp/wind/wind_inst.html#TGRS
Group: Instrument_Logistics
Instrument_Start_Date: 1994-11-01
Instrument_Owner: NASA
End_Group
End_Group
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