Operations

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.

To Ramp Up

1. Confirm that the shim PS is powered ON (if you can go in the hall).
2. Press "To Zero".
3. Press the Toggle button of the main switch heater.  It turns on both the main and shim switch heaters.
   1. When you use the PS front panel, you press additionally the two buttons of the shim switch heaters on CCP, to turn them on.
4. Confirm that the two LEDs on the shim PS are ON (if you can go into the hall).
5. Set "2 A/m" and "45 A".
   1. You can use the "Presets" selector, or enter the values into the text boxes.
6. Press "To Set" and wait until the current becomes the set point (SP) and "HOLD".  It takes 23 minutes.
7. Set "1 A/m" and "63 A".
8. Press "To Set" and wait until the current becomes the SP and "HOLD".  It takes 18 minutes.
9. Set "0.5 A/m" and "74.78 A".
10. Press "To Set" and wait until the current becomes the SP and "HOLD".  It takes 24 minutes.
11. Switch to the persistent mode, if you want.

Reference: UVA elog 154

To Switch to Persistent Mode

1. Press the Toggle button of the main switch heaters.  It turns off both the main and shim switch heaters.
2. Press "To Zero" and wait until the current becomes 0 A and "HOLD".  It takes 4 minutes, where the ramp rate is slow at the beginning.

To Switch from Persistent Mode

1. Confirm that the shim PS is powered ON.  If not, turn it on and check why it was off.
2. Confirm that the main and shim switch heaters are OFF.  If not, something is wrong.
3. Set "74.78 A", using the Presets selector.  The ramp rate becomes "0.5 A/m" but it will not matter.
4. Press "To Set" and wait until the current becomes the SP and "HOLD".  It takes 2.5 minutes.

5. Confirm that "Clamped Rate Limit Quench" is not red.

To Ramp Down

1. Switch back from the persistent mode, if necessary.
2. Press the Toggle button of the main switch heater.  It turns on both the main and shim switch heaters.
3. Set "0.5 A/m" and "63 A".
4. Press "To Set" and wait until the current becomes the SP and "HOLD".  It takes 24 minutes.
5. Set "1 A/m" and "45 A".
6. Press "To Set" and wait until the current becomes the SP and "HOLD".  It takes 18 minutes.
7. Set "2 A/m" and "0 A".
8. Press "To Set" and wait until the current becomes the SP and "HOLD".  It takes 23 minutes.
9. Press the Toggle button of the main switch heater.  It turns off both the main and shim switch heaters.

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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.

Image Added

Procedures

(A) To Ramp Up

(B) To Switch to Persistent Mode

(C) To Switch from Persistent Mode

(D) To Ramp Down

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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