Liquid Nitrogen
Gammasphere's detectors use germanium that needs to be kept at a specified temperature to stay intact. Gammasphere uses liquid nitrogen within each detector that maintains the thermal requirement. Each detector has a nitrogen tank that has to be filled with nitrogen, a process that is completed through something called an LN system, where a large tank gives gaseous nitrogen and given to “solenoids” that provide a valve to control the flow of nitrogen to each detector as liquid nitrogen. The system is controlled through the VME computer, and the fill process for Gammasphere detectors is done at least twice daily. Failure to fill a detector's Dewar will result in damage to the Ge crystal, which is a costly and time-consuming process to repair. If a detector leaks or loses the necessary temperature level at any point, an alarm sets off.
LN Fill System EPICS Screen
Below is the main screen for the Liquid Nitrogen fill system, which allows a user to fill each tank of Gammasphere's detectors. It is an image map - click on the buttons in the picture to go to the page for that item.
Go back to Gammasphere Detectors