The Alcohol Bubblers

To reduce the rate of aging of the wire chambers, the operating gas contains a small quantity of alcohol vapor. The vapor is added by bubbling the argon/ethane mixture through liquid alcohol. The temperature of the alcohol controls the alcohol vapor pressure, which determines the amount of vapor added to the gas. The alcohol content also affects the electron dirft velocity in the wire chambers, so it must be held approximately constant.

To refill the alcohol bubblers:

The alcohol bubbler system features a refill system that allows filling directly from the bottle, minimizing exposure of the alcohol to air and reducing the possibility of a spill. The reservoirs should be refilled before they become empty to maintain a head of liquid over the float valve which will prevent air from entering the system. In the back of the gas system rack is a holder for gallon sized alcohol bottles and a cap with dip tube. Place a new bottle in the bottle holder and replace the cap with the cap with dip tube.

Step-by-Step Instructions for Refilling the SOS Alcohol Bubbler

These steps must be individually completed in the order listed!
Refer to Fig. 1.

1. If needed, install a full bottle of alcohol in the back of the gas racks as mentioned in the preceeding paragraph.
2. Open valves 8,9. Close valves 7,10 to Put the SOS alcohol bubbler in BYPASS.
3. Close valve 16 to isolate the warm reservoir gas from the bubbler.
4. Open valve 15 to bleed off the warm reservoir gas pressure.
5. Certify that the pressure feeding valve 19 is 1 psi or less so that you do not cause the alcohol bottle to explode when you pressurize it. Wear safety glasses!!
6. Open valve 19 to pressurize the alcohol bottle.
7. Open valve 21 to flow alcohol into the warm reservoir.
8. When the alcohol level in the sight-glass is within 2cm of the top, stop the flow of alcohol: Close valve 21.
9. Close valve 19.
10. Open valve 16.
11. Close valve 15.
12. Open Valves 7 and 10. Close Valves 8 and 9.
13. Record what you did in both the gas logbook and the electronic logbook.

Step-by-Step Instructions for Refilling the HMS Alcohol Bubbler

These steps must be individually completed in the order listed!
Refer to Fig. 1.

1. If needed, install a full bottle of alcohol in the back of the gas racks as mentioned in the preceeding paragraph.
2. Open valves 12,13. Close valves 11,14 to Put the HMS alcohol bubbler in BYPASS.
3. Close valve 18 to isolate the warm reservoir gas from the bubbler.
4. Open valve 17 to bleed off the warm reservoir gas pressure.
5. Open valve 19 to pressurize the alcohol bottle.
6. Open valve 20 to flow alcohol into the warm reservoir.
7. When the alcohol level in the sight-glass is within 2cm of the top, stop the flow of alcohol: Close valve 20.
8. Close valve 19.
9. Open valve 18.
10. Close valve 17.
11. Open Valves 11 and 14. Close Valves 12 and 13.
12. Record what you did in both the gas logbook and the electronic logbook.

Alcohol Temperature Control

To keep the alcohol temperature (and thus the vapor pressure) constant, the alcohol bubblers are housed in refrigerators which are controlled by electronic temperature regulators having 1 C sensitivity. Both controllers are located on a shelf in the left rack of the gas mixing system. Normally, the actual temperature in each refrigerator is indicated on the front panel of the controller. Both controllers should be set to maintain a temperature of 1 C.