...
Cherenkov counters settings
Cherenkov Settings:
Electron runs:
- Discriminator threshold: C1=140 mV, C2=150mV
- Pressure settings- For electron runs:
Energy | C1 pressure | C2 pressure |
|---|---|---|
0.5 GeV | 0.9 bars | 0.95 bars |
1 | 0.9 | 0.95 |
2 | 0.8 | 0.95 |
3 | 0.8 | 0.95 |
4 | 0.5 | 0.6 |
5 | 0.3 4 | 0.3 4 |
6 | 0.22 | 0.22 |
7 | 0.18 | 0.18 |
|
|
|
|
|
|
Proton runs:
- Discriminator threshold: C1= 30 mV, C2 = 30 mV
- Pressure settings For proton runs:
Energy | C1 pressure | C2 pressure |
|---|---|---|
6 - 10 GeV | 2 bars | 2 bars |
Instructions to set Cherenkov counters pressure
Note: at least once a day the cherenkov counters need to be completely evacuated and refilled. This operation takes about half an hour.
The Cherenkov rack is divided in two parts: the upper part for C1, the lower part for C2. All the operations must be performed on both Cs.
How to empty Cherenkov counters:
...
If the pressure is <1 bar follow the instructions below:
- Raise the power lever Turn on the pump power switch located on the wall just behind the Cherenkov rack
...
- Open the general T9 Cherenkov (CO2) pump located on the upper part of the rack that you find just in front of the door of the Cherenkov area. On the first line there are four red levers. Open the lever at the right of the line (just above the yellow notice "T9 cherenkov"), by turning it anticlockwise in the vertical position.
- In the C1 and C2 Cherenkov rack, open completely levers n.1 and n.2 (for both cherenkovs) then very slowly open lever n.3 to let gas go into the pump. Do NOT open lever n.3 completely but adjust it always at a small angle with respect to the horizontal.
- Remember to check often the pressure value during the filling operation by closing lever n.3 (horizontal position).
- Once you have reached the pressure value you want close levers n.3, n.2, n.1
- Go back to the general Cherenkov rack and close the main T9 cherenkov lever (horizontal position)
Thresholds