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Wide Band Spectrometer

NSSDCA ID: 1991-062A-03

Mission Name: Yohkoh
Principal Investigator:Dr. Jun Nishimura


The Wide Band Spectrometer (WBS) consists of three subinstruments that together span the energy range from 2 keV to 100 MeV. They are (1) the soft X-ray spectrometer (SXS), a gas proportional counter filled with Xe and CO2 that covers the 2 to 30 keV band, (2) the hard X-ray spectrometer (HXS), a NaI scintillator that covers the energy range 20 - 600 keV, and (3) the gamma-ray spectrometer (GRS), a pair of identical BGO scintillators (Bi4 Ge3 O12), that cover the 0.2 - 100 MeV band. SXS has a FOV 10 deg square, has a sensitive area of approximately 12 cm**2, divides its energy range into 128 channels, and records 128-channel spectra every 2 s, 2-channel spectra every 0.25 s. The energy resolution at 5.9 keV is approximately 20% (FWHM). The HXS records pulse height data in 32 quadratically spaced channels over the 20 - 400 keV range every 1 s, and 2-channel pulse count data for the bands 20 - 50 keV and 50 - 600 keV every 0.125 s. The GRS has a resolution approximately twice that of the HXS, and records a 128-channel energy-loss spectrum, which is processed via spectral deconvolution to yield the incident gamma- ray spectrum. 128-channel spectra are recorded every 4 s. An assortment of other time resolutions apply for various energy channels. GRS also has detection sensitivity to solar flare neutrons.

Alternate Names

  • Yohkoh/WideBandSpectrometer

Facts in Brief

Bit rate (avg): 0.001 kbps

Funding Agency

  • Institute of Space and Aeronautical Science, U of Tokyo (Japan)


  • Solar Physics: X-Ray
  • Solar Physics: Visible

Additional Information

Questions and comments about this experiment can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Mr. Mons D. MorrisonExperiment Data ManagerLockheed Palo
Mr. Sam FreelandGeneral ContactLockheed Palo
Prof. Ichiro KondoOther InvestigatorShibaura Institute of Technology
Mr. Tetsuya WatanabeOther InvestigatorNational Astronomical Observatory of
Dr. Jun NishimuraPrincipal InvestigatorInstitute of Space and Aeronautical

Selected References

  • Morrison, M. D., et al., Solar-A reformatted data files and observing log, Solar Phys., 136, No. 1, 105-110, Nov. 1991.
  • Yoshimori, M., et al., The Wide band spectrometer for the Solar-A, Solar Phys., 136, No. 1, 69-88, Nov. 1991.
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