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User name Sulkosky
Log entry time 20:47:40 on August25,2003
Entry number 113473
keyword=Right Dipole NMR not locking
When shift began, the Right dipole was ramping up, but after the current got past the set point the magnet NMR never locked. JP and I attempted to search for the signal manually but did not succeed. We talked to John LeRose, and he suggested that we should check the power supply for the compensation coil. We made a controlled access and found the power supply. It appears that the power supply is in remote mode, since we could not change the set reading on the front panel, which read zero. So we had the crew in the Counting House change the set point on the NMR GUI, however this did not change the reading on the power supply which remained at zero. We then turned off the power supply and turned it back on. This also did not fix the problem.
For the time being we set the current on the Dipole to the current reading from when we ran at 4.4 GeV beam energy. After talking to John LeRose again, he said it sounded like a IOC communication problem. I then asked him about setting the current instead of the momentum and he said it would be better to look at the NMR readings from the start of run files and the Hall probe readings (which are not in the start/end of run files). I was able to find some HALOG entries where the Hall A Tools page was captured. From this information, I was able to find the scaling value for the Hall probe reading. This value is -2.724 GeV/T. For now I will try to find the correct set currents for the first few kinematics until the problem is fixed.