The Large Area Counter on Ginga
Abstract
The large-area counter on the third Japanese X-ray astronomy satellite Ginga is described. It comprises eight multicell proportional counters with a total effective area of 4000 cm², covering the energy range 1.5 to 37 keV. The energy resolution is 18% at 6 keV, and scales as E-0.5 over the full energy range. The field of view of the collimator is elliptical (1.°1 × 2.°0 FWHM), giving a 3σ confusion limit of about 0.2 mCrab. Shielding against the diffuse cosmic X-ray background and anticoincidence background rejection techniques give an in-orbit background of 3.5 × 10-4 counts cm-2 s-1 keV-1. The LAC is able to measure the spectrum and study the time variability of X-ray sources down to about 0.2-mCrab intensity. The ultimate time resolution is 1 ms, and the large area gives significant counting rates from bright sources in time bins a few ms long.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- August 1989
- Bibcode:
- 1989PASJ...41..345T
- Keywords:
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- Astronomical Satellites;
- Crab Nebula;
- Gamma Ray Bursts;
- Ginga Satellite;
- Proportional Counters;
- Spaceborne Astronomy;
- X Ray Astronomy;
- Japanese Space Program;
- Relic Radiation;
- Satellite-Borne Instruments;
- Spacecraft Instrumentation;
- Crab Nebula;
- Instruments;
- X Ray Astronomy