SVT RECOVERY PROCDURES

Beam trips at 0.5:

SVT HV will trip off automatically upon a halo counter beam trip. On a beam trip, check the FSD status GUI.

• If it was NOT an HPS halo counter trip, MCC should restore the beam on their own. The HV STATUS indicator should remain green as the bias voltage stays at 180V.
  1. When beam is restored, check that the BPM x and y values at 2H02 are as desired and that beam current is stable at our desired value.
• If it was an HPS halo counter trip, MCC will not restore the beam until we request it. Call MCC, tell them that we will get back to them when we are ready for beam (stay on the line).
  1. The HV STATUS indicator should turn yellow as the bias voltage is ramping down. It will turn red once the bias voltage is at 5V. If this does not happen after about 10 seconds, manually press the 5V button in the SVT Summary GUI. (and call SVT expert)
  2. Once the status indicator turns red, tell the MCC we are ready for beam.
  3. When restored, check that the BPM x and y values at 2H02 are stable as defined in the orbit locks and that halo counter rates are the same as before the trip.
  4. Restore SVT HV. Watch the HV STATUS indicator turn yellow, then green.
  5. Reset the SVT monitoring plots (disconnect and connect). Check the SVT monitoring plots.

Long down:

If beam is down for an extended time (more than 15 minutes) or MCC calls to say beam will be down for an extended time:

1. Press the 5V button in the SVT Summary GUI. Check the HV STATUS indicator turns yellow, then red.
2. Retract the SVT to its 1.5 mm stations, both top and bottom. Check the POSITION STATUS indicator turns red.
3. When beam is restored, check that the BPM x and y values at 2H02 are stable as defined in the orbit locks and that halo counter rates are the same as before the trip.
4. Restore SVT HV. Check the HV STATUS indicator turns yellow, then green.
5. Move the SVT back to 0.5 mm, both top and bottom. Move in steps (1.0, 0.7, 0.5). Watch bias currents and halo counter rates. Check the POSITION STATUS indicator turns green at 0.5 mm.
6. Reset the SVT monitoring plots (disconnect and connect). Check the SVT monitoring plots.