A mechanical cooler for the spectrometer experiment on board the integral spacecraft

摘要

The International Gamma Ray AstrophysicsLaboratory (INTEGRAL) is an ESA satellite to be used for gammaray astronomy. The detector of the gamma ray spectrometer is keptto its nominal temperature of 85 K by means of a mechanicalcryocooler system. The cryocooler system, developed by MMSBristol, consists of four 50-80 K Stirling cycle coolers, controlledby two drive electronics units, coupled such that coolingperformances are guaranteed after one failure. The four displacershave a common interface, via a beryllium rod, to the instrumentdetector. In nominal operations the heat lift capability provided atthe cryocooler interface will exceed 2000 mW at 80 K. Thepurpose of this paper is to present the cryocooler design and toreview the main thermal, mechanical and accommodation aspectsrelevant to its installation and operation on the instrument andspacecraft. A brief description of the detector cryostat is also given.The measured performances of the cryocooler in the variousmodes of operation will be summarised and a brief survey of themodel philosophy and qualification test program will be presented.