Operations
To Ramp Up
(See UVA elog 154; http://twist.phys.virginia.edu:8081/General/154)
- Confirm that the shim PS is powered ON.
- Press "To Zero".
- Turn on the main and shim switch heaters.
Confirm that the two LEDs on the shim PS are ON.
- Set "2 A/m" and "45 A".
- Press "To Set".
- Wait until the current becomes the SP. Should take 22.5 minutes.
- Set "1 A/m" and "63 A".
- Press "To Set".
- Wait until the current becomes the SP. Should take 18 minutes.
- Set "0.5 A/m" and "74.78 A".
- Press "To Set".
- Wait until the current becomes the SP. Should take 24 minutes.
To Switch to Persistent Mode
- Turn off the main and shim switch heaters.
- Press "To Zero".
- Wait until the current becomes 0 A. It will be slow at the beginning. Should take 4 minutes.
To Ramp Down
(See UVA elog 174; http://twist.phys.virginia.edu:8081/General/174)
- Confirm that the shim PS is powered ON. If not, turn it on and check why it was off.
- Set 74.78 A.
Heater should be switched off during this operation.
Check that "Clamped Rate Limit Quench" should be not red.
Once current in power supply reached at magnet current 74.7802 Amp then power supply should attains the HOLD.
Wait for 20 seconds then turn on the "Heater ON".
After Set the current at 63.0 Amp and set rate at 0.5 Amp/min then go to Home and then press in the "To Set" this shows "Rate limit" on the home screen.
After reached at 63.0 Amp.
Set current at 45 Amp and set rate at 1 Amp/min and goto the main screen wait 20 seconds and then press on "To Set".
After reached at 45 Amp.
Then set current at 0 Amp and set rate at 2 Amp/min and then go to the home screen wait for 20 seconds and then select "To Set".
Once it reached at 0 Amp this will goes to "Hold" automatically.
Wait for 20 seconds and then turn of the "Heater OFF" And Turn off the Shim power Supply.
The following procedures suppose that you use the remote control interface (i.e. Cryo Control Panel; CCP). When you use the front panel of the magnet PS, some button operations are different.
Precautions
- The magnet LHe level is so high (>20%??) that LHe remains even if soft quench happens.
- A time to ramp up/down the magnet should be planned in advance, since it takes at least 1.5 hours.
- You should remember that any deviation from the standard procedure might cause quench.
- You are expected to know what should happen at each step and confirm that it happened. You had better go through this procedure with another person who has already carried it out.
- You should search for any indication of quench during the operations, such as error messages on the magnet PS, sudden changes of Tank B, Coil T, Coil B, the magnet pressure, etc.
- You can use this chart preset: https://e906-gat1.fnal.gov/data-summary/e1039/target-par-preset/magnet_ramp.php
Unlocking Controls
All controls on VI are usually locked, to avoid mis-operation. When you need controls, you have to click the "All Controls: Locked" button. It is preferable to apply the lock when you finished controls.
Procedures
(A) To Ramp Up
(B) To Switch to Persistent Mode
(C) To Switch from Persistent Mode
(D) To Ramp Down
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Documents
- ORC 2049 - ORC of Super conducting magnet electronic connectors (in the target cave)
- oxford_seppo_magnet_cryostat_handbook.pdf
- oxford_seppo_work_notes.pdf
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