Magnets
In the process of editing and updating this page. Please contact Juliette Mammei crowder@jlab.org with questions or suggestions.
PREX Main<< HOW TOs
Nominal Settings
- Left HRS: Q1: 146.42 A/GeV; Q2: 434.42 A/GeV; Q3: 536.12 A/GeV
- Right HRS: 146.57 A/GeV; Q2: 435.98 A/GeV; Q3: 539.51 A/GeV
- Septum:
- Tune: B
Setting the Magnets
If one can not reset the magnet remotely: Do NOT go into the hall to reset by yourself. Contact RC and then tech on-call/magnet expert.
For PREX, regulators for Q1, Q2, Q3 are always OFF and only used for the dipole. Q1, Q2, Q3 magnets will be set by current. NEEDS TO BE VERIFIED
Set HRS Magnets
- Clear all faults (if there are still problems with flows or liquid levels there is no point ramping back up to crash again).
- Check regulator OFF for Q1, Q2 and Q3. Leave the dipole regulator ON
- Set the momentum of the spectrometer you want. The dipole should start moving towards that setting. The NMR will be set too. Q1, Q2 and Q3 will not change.
- Turn on the Q1 power supply if not on already
- Run the Q1 power supply to 900 A. Let it stay at the maximum there for about five minutes
- Set the desired current for the left/right Q1.
- Procedure for Q2 and Q3 is similar but with different values to cycle the magnets: 1600A for LQ2, LQ3, and 1400 A for RQ2, RQ3. Do NOT leave RQ3 at 1400 A more than 5 min (but leave it there for 1 min)!!
Set Septum Magnet
We do NOT currently set the septum. We ask MCC for it.
To check the septum current:
- In JMenu:
- Operations < Magnets < Special Hall Magnets < Septum Magnet (Hall A)
- The Hall A Septum screen will come up (see Figure 1)
- The setpoint and readback values should be close to 430 A (check white board)
Monitoring the Magnets
HRS
GUI can be found at:
OPS Menu -> EDM (HLA) -> Hall A -> Tools Display
How to check polarity
LHRS dipole, RHRS Q1 and dipole polarity changes require an access. The rest can be changed with the power supply gui.
One should check the polarity with Gaussmeter. The Hall probes should read positive for positive particles and negative for negative particles (WITH CURRENT IN THE MAGNETS)
Septum
GUI can be found at:
OPS Menu -> EDM (HLA) -> Hall A -> Magnets -> Super Big Bite
