Liquid Nitrogen Filling for AYEball
There are two LN filling system currently being used by AYEBALL: (1) Standard
BGO and (2) Daresubury.
Before Filling
- Check High Voltage for Ge detectors to insure that no detector has shut off its bias. If it has, consult someone if you are not sure what to do.
- Pause data acquisition (type PAUSE in front end window).
- Check levels in both LN tanks to insure that they are NOT empty.
- See if any bayonets are hanging. Either install them or do not enable those channels in the autofill systems.
Fill Instructions
Standard BGO
- Push all reset buttons on the controllers.
- Turn on switches for filling each detector.
- Push fill button on Main Controller.
- Feel the exhaust for each detector.
- If it is missing or weak turn off that detector and take corrective action (fill by hand, change bayonet, call for help, etc.).
- No sensors are connected to LN control system. When the overflow line for a detector clearly shows liquid, turn off fill to that dectector at control box. Continue until all switches are off.
- Record time and comments for fill in green log book.
Daresbury
- Turn off all filling to detectors. Turn on filling to Manifold (solenoid switch on main
controller).
- Push fill button on Main Controller. The sensor for the manifold is
connected and thus will automatically shut off when the overflow resistor
senses liquid.
- Once the manifold shuts off, turn off filling to Manifold and turn on
filling to detectors.
- Push fill button on Main Controller.
- Feel exhaust lines.
- No sensors are connected to LN control system. When the overflow line shows liquid, turn off fill to dectector
at control box.
- Record time and comments for fill in log book.
After Fill
- Turn all swithces back on (except for detectors for which you have removed a bayonet and the switch for the manifold on the Daresbury system) and reset any errors and alarms.
- Make sure both main controllers are reset to 12hrs.
- Check levels in both LN tanks to insure that they are NOT empty. If either
tank is empty replace it with new tank. Do NOT leave an empty tank for the next person!
- Make sure LN tank valves are open. In case someone forgets to fill, it will happen automatically.
- Resume data acquisition (type RESUME in front end window).
Last Updated: October 24, 1995 (D. Blumenthal)