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Position Sensitive Proportional Counter (PSPC)

NSSDCA ID: 1990-049A-02

Mission Name: ROSAT
Principal Investigator:Prof. Joachim Truemper


The position sensitive proportional counter (PSPC) was a thin-window gas counter. Incoming photons were absorbed, producing an electron cloud proportional to the photon energy. The electron cloud drifted to the anode wire grid where a high voltage was applied. In the high electric field, close to the wires, gas amplification of about 50,000 took place producing a charge signal at the anode wires which was proportional to the energy of the incoming photons. Simultaneous charge signals were induced in two cathode wire grids close to the anode. These signals were used to obtain the position of the photons with an accuracy of about 120 micrometers. A rotating filter wheel, in front of each PSPC, allowed the selection of reduced photon energy bands. In one position, the filter wheel was utilized as a vacuum door containing three radioactive sources for calibration.

Alternate Names

  • PSPC

Funding Agency

  • Max-Planck-Institut (Federal Republic of Germany)


  • Astronomy: X-Ray

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Horst HippmannOther InvestigatorMax-Planck-Institut fur Extraterrestrische
Prof. Joachim TruemperPrincipal InvestigatorMax-Planck-Institut fur Extraterrestrische

Selected References

  • Snowden, S. L., et al., ROSAT detection of an X-ray shadow in the 1/4-keV diffuse background in the Draco nebula, Science, 252, No. 5012, 1529-1532, June 1991.
  • Burrows, D. N., and J. A. Mendenhall, Soft X-ray shadowing by the Draco cloud, Nature, 351, No. 6328, 629-631, June 1991.
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