Liquid Nitrogen

Gammasphere's detectors use germanium that needs to be kept at a specified temperature to stay intact. For this reason, Gammasphere uses liquid nitrogen within each detector to maintain the thermal requirement. This is done through something called an LN system, where liquid nitrogen is given to each tank at least twice a day. The system is controlled through the VME computer. If a detector leaks or loses the necessary temperature level at any point, an alarm sets off.