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    User name A. Deur

    Log entry time 00:01:10 on November24,2009

    Entry number 302234

    keyword=Swing shift summary

    16:00 Shift started with controlled access to swicth polarity of HRSs for positron runs. There is a question on the validity of the RHRS Q3 polarity (See Jian-Ping and then Jack entry). Jack is in the hall checking the gaussmeter and whether the power supply does change polarity or not.
    17:10 Call MCC to terminate the access.
    17:20. MCC ready to send beam, but target is still moving to empty position.
    17:22 target ready. Asked for 2 uA of non-rastered beam. We bypass the harp-scan since there were no work on the accelerator side. We start recovering procedure with BeO.
    Beam position looks good on BeO and BPMs.
    We are now moving the optics target to check left harm optics. Left HRS VDC turned on. (RHRS dipole still ramping up). Requested 5 uA of beam, unrastered. LHRS run number: 25713 (also took a useless run on RHRSL: run 5264).
    17:47 Turning off VDC, asked for 5 uA of 4*4 rastered beam.
    17:50 start LHRS run 25714 and checked 4*4 raster size with spot++. Looks reasonable. We move to the LD2 target.
    18:01 LD2 target ready. Request 2 uA of 4*4 rastered beam.
    LHRS run number: 25715. Left arm T1 scaller: 5.6 kHz. check raster sized with spot++. Looks okay.
    18:05. Now requesting 2 uA with 6*6 raster
    18:09 Start run 25716. LHRS scaler rate: 5.3 kHz. => looks fine. Check with spot++. Looks good
    18:10 requesting mow 110 uA for production run. (LHRS only, RHRS dipole still ramping up).
    18:14 We have 110 uA. Starts LHRS run: 25717. parity run#:14179
    19:00 We get a lot of beam trips. After checking with spokesperson, we called MCC to ask to lower the current to 100 uA. (beam high current not too necessary for e+/e- runs)
    19:05. RHRS dipole still not locking. Request controled access to check compensating coil. Meanwhile, prepare for RHRS Q3 polarity check: bring the optics target in and turn off raster. L&R VDC turned on.
    19:36. Jack turned on the compensating coil. Dipole has now locked. Calling MCC for beam. (5 uA, no raster).
    19:42: RHRS dipole finally ready. Now waiting for beam.
    19:52 5 uA in Hall A. Rates are too small -> increase to 10 uA.
    running LHRS run
    Jin's analysis show that RHRS Q3 polarity is wrong. We are setting it to 0 now (since Jack told us we can't reverse polarity). This is good news. It means the data taken before the HRS polarity change are with the right 3 polarity. See Jin's detailed entry.
    Run 5266 is with Q3 ramping and then ramped down.
    20:09 Start runs 25721 and RHRS 5267, with RHSR Q3=0. Jin is checking the optic but we can see the rate is higher than with Q3 on, so this is confirming that Q3 has the wrong polarity for the e+ run.
    20:16 Done with optic check on Q3. Called MCC in order to move to LD2 target.
    20:24. Target ready. request 2 uA of 6*6 rastered beam, to figure out what current and prescale value to run at.
    runs 25722 & 5268 are junks.
    20:28 start production runs with VDC on and 2 uA. Runs 25723 & 5269
    and parity 14180.
    21:28 Runs completed. Start runs Runs 25724 & 5271 and parity 14181, same conditions. Run 5270 is a short run (consider it junk).
    22:17. Ramesh is here for his deadtime study. We stop the runs, ramp down the VDC. Meanwhile Xiaowei is doing a short test run with the parity DAQ: 14182.
    22:22 VDC off. Requesting now 60 uA for Ramesh's study.
    22:25 Startings runs 25725 & 5272 and parity 14182.
    22:46. Stopped the runs. Requested 80 uA. Started runs 25726 & 5273 and parity 14185.
    23:14. Stopped the runs. Requested maximum convenient beam current (hopefully 110 uA). Runs 25727 & 5274 and parity 14186 are on going.
    These runs are for the end of Ramesh deadtime study and also part of the 2.5h high current e+/e- runs.
    22:25 Startings runs 25728 & 5275 and parity 14187 (parity run started only at 23:58).