Downtime expected shortly as all LEDAS services are moved to a new server.
The Ginga mission
Ginga was the third Japanese X-ray astronomy satellite. It
was launched into low Earth orbit on 5th February 1987 and
re-entered the atmosphere on 1st November 1991. The
scientific payload consisted of the Large Area Counter (LAC; Turner
et al. 1989), the All-Sky Monitor (ASM; Tsunemi et al.
1989) and the Gamma-ray Burst Detector (GBD; Murakami et al.
1989). A full description of the satellite is given in Makino et
al. (1987). During its lifetime Ginga performed over 1000
pointed obersvations of approximately 350 different targets, covering
all then known classes of cosmic X-ray sources.
The LAC experiment, sensitive to X-rays
with energy 1.5-37 keV, consisted of an array of eight collimated
co-aligned proportional counters with a total effective area of
approximately 4000 cm² and energy resolution of 18% at
6 keV, scaling as E-½
throughout the full energy range. In each counter the
anode structure was of a multi-layer and multi-cell design which
provided both gain uniformity and low internal background through the
use of anticoincidence. The high voltage supply was normally operated
at ~1830 V, but was reduced occasionally to ~1745
V to achieve a larger energy range. Steel
collimators restricted the field of view to 1.1 x 2.0
degrees (FWHM); the top and bottom 15 mm were coated with silver
paint to prevent contamination through iron, nickel and chrome
fluorescent lines. The fluorescent line of silver at 22.1 keV can
be visible at high energy but it is well away from lines of
astrophysical importance and can be used for calibration.
[Next: The Ginga Database]
[Back to Introduction]