Large Area Proportional Counter

The LAC instrument for Ginga
The LAC instrument for Ginga

Ginga’s primary science instrument was the Large Area Proportional Counter (LAC). At the time, the LAC was the largest X-ray detector flown on a satellite. The LAC consisted of 8 identical proportional counter units.

When an X-ray entered the LAC, it would enter a chamber filled with a mixture of argon, xenon and carbon dioxide gases. The X-ray would interact with the gas, causing a cascade of electrons that would be detected by the LAC electronics. The LAC was sensitive to X-rays in the range of 1.5 to 37 keV.