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.

Precautions

• No operation can be made when the magnet is being filled with LHe.

• A time to ramp up/down the magnet should be planned in advance, since it takes at least 1.5 hours.

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.

Reference: UVA elog 174

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

t.b.w.