A COMPUTER-PROGRAMMABLE DELAY-GENERATOR SCHEME FOR THE TACTIC GAMMA-RAY TELESCOPE

A programmable multi-channel digital-delay generator, characterised by negligible dead-time count losses, has been developed for deployment in the high-sensitivity TeV gamma-ray telescope, TACTIC. This telescop e comprises an array of 4x10 M2 of light collectors, of which three ar e placed at the comers of an equilateral triangle of side greater-than -or-equal-to 20 m and are operated in a prompt-coincidence mode with a resolving time of approximately 10 ns to detect atmospheric Cherenkov events produced by very high energy gamma-ray and cosmic-ray proton p rimaries. The delay generator helps to line up these events in real ti me whenever they are detected at different relative times by these ele ments. The basic circuit used in this scheme can be readily adapted fo r utilisation in several other areas, including experimental nuclear p hysics.