User name vasulk
Log entry time 21:41:25 on April24,2003
Entry number 98545
This entry is a followup to: 91326
keyword=Target Correction CoilsFigure 1 shows the controls for the Polarized Helium-3 correction coils. The controls can be found by going to the Hall A main menu and choosing "Magnet Controls" then "Hall A Corrector Coils".
Power Supply MHC1H04A controls the Transverse correction coils.
Power Supply MHC1H04B controls the Upstream Longitudinal correction coil.
Power Supply MHC1H04C controls the Downstream Longitudinal correction coil.
Power Supply MHC1H04D controls the Vertical correction coils.
There are significant gradients in the target region due to fringe fields from the Septum Magnet. Without correcting for the fields, the polarized cell will lose significant polarization. At low to medium currents on the Septum magnet, the main gradient is along the beam line. Before the experiment, the field gradients were measured at various Septum magnet currents. Then the gradients were remeasured with the correction coils on. I am currently working on a operating procedure for using the correction coils. At present the Downstream Longitudinal Correction coil is on. In the target logbook, there is a list of values at which to set the correction coil for the first two kinematics. When the Septum magnet current is changed, the correction coil current should also be changed. However you should change the currently slowly, since it is possible that a suddenly large change in the correction coil current could cause a quench in the Septum Magnet. Only a target operator should adjust the correction coil currents.
FIGURE 1
