ASCA's Gas Imaging Spectrometers
ASCA's two Gas Imaging Spectrometers (GIS) were built by scientists and engineers at Tokyo University. The GIS, an imaging gas scintillation proportional counter, has two main parts: the gas cell, and the photon- sensitive phototube.
The gas cell is filled with a mixture of xenon (90 percent) and helium (10 percent). The cell has a front window made of beryllium (10 microns thick). The voltage across the gass cell is 8000 V.
The phototube was made by scientists and engineers at Hamamatsu Photonics. It has a quartz window (7.5 cm thick) and ten-stage dynodes.
The area of the GIS that is sensitive to X-rays is 50 mm in diameter. Other "vital statistics" of the GIS are as follows:
- Energy Range : 0.7 keV to 10 keV
- Energy Resolution: 8 percent at 5.9 keV
- Field of View: circular, with a diameter of 50 arcmin
More GIS Information
- GIS monitor counts
- GIS news
- GIS calibration data
- Important events on GIS during the ASCA mission
- GIS information anonymous ftp area
- GIS articles in the ASCA newsletter:
- GIS Status Report: January 24, 1994
- GIS3 CPU trouble between Feb 10 to April 8, 1994 ( how to analyze these data)
References: Ohashi, T. et al. 1996, "The Gas Imaging Spectrometer on Board ASCA", PASJ, 48, 157 Makishima, K. et al. 1996, "In-Orbit Performance of the Gas Imaging Spectrometer onboard ASCA ", PASJ, 48, 171 Yasushi Ikebe's doctoral thesis (1995, Univ of Tokyo), "X-ray Measurements of Mass Distribution in Clusters of Galaxies" Tashiro, M. et al. 1995, "In-orbit performance of the GIS instrument on-board ASCA (Astro-D)", SPIE, 2518, 2 Kohmura, Y. et al. 1993, "Calibration of imaging gas scintilation proportional counters on Astro-D", SPIE, 2006, 78 Ohashi, T. et al. 1991, "Imaging gas scintillation proportional counters for Astro-D", SPIE, 1549, 9
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