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    User name P. Monaghan

    Log entry time 00:46:57 on January18,2005

    Entry number 139547

    keyword=Swing Shift Summary

    SL: Peter Monaghan
    TO: Yi Qiang
    3rd: Eddy Jans

    16:00 Shift begins with run #1897 at 2uA current starting, as part of a timing test for our auxiliary plane detector.

    16:24 MCC called to inform us that their RF group was going to replace a flowmeter that was causing them problems and they would be down for around 15 minutes.

    16:50 Beam back; Bodo and Olivier are still trying to figure out why the TDC spectrum for the auxiliary has a huge peak much earlier than expected.

    17:35 Bodo and Olivier decide to do a test with only one single auxiliary channel switched on (trigger plane still switched on) - run 1901; going to check the TDC spectrum for a single channel.

    18:23 The TDC spectra from the auxiliary plane are still puzzling everyone and after much staring at plots and scratching of heads, Bodo and Olivier decided we should ask for an access to go and double check the auxiliary plane trigger/logic modules. Called MCC to ask for a controlled access.

    20:30 Finally left the hall and asked MCC to go to beam permit. We decided to change the discriminator threshold setting for the auxiliary plane from -45mV to -100mV. The reason was that on the lower setting we had seen a large amount of after-pulses on the discriminator signal. After the change in threshold setting, the total rate for cosmic signals on the auxiliary plane was halved.

    We looked at the neutron detector channel N1-27L which was giving a low scaler readback value. The amplifier and discriminators appear to be working properly, but the raw signal going into the amplifier for this channel appears weaker than others. The high voltage may need to be increased a little, although we have not done so yet because it might be wiser to reset the gains on all channels now we are in production mode.

    20:40 MCC deliver 8uA beam back into the hall.

    21:40 Called MCC and asked for another short, escorted controlled access to remove delay from our TDC start signals. Bodo and Olivier figured out that the auxiliary plane tdc signal was about 30ns different from the tdc signal for the E and dE planes. We decided to make an entry to remove some delay (14ns in the delay box) from the trigger start, to have the auxiliary tdc starting at a much higher channel number than it does currently.

    22:10 MCC restore 8uA beam to the hall after our controlled access. First we do a test run (1912) with only T6 triggers to look again at the TDC spectra for the auxiliary, dE and E planes.

    00:00 Continue to start taking data in the x>1 physics configuration. However, looking at the online detector replay for run 1913, the TDCs for S2 in the left arm do not appear to be working. This is being investigated.


    ---------------------------------------------------------------
    Run Summary

    L-HRS; 19.5 degrees; p=-3.762 GeV/c
    R-HRS; 40.1 degrees; p=1.450 GeV/c
    BigBite; I=518 A; B= 0.9325T - still no read back for the current setpoint.
    Target - 12C tilted.

    1897 16:00 - 16:13 200K; 2uA; ps6=100.
    1898 JUNK
    1899 16:17 - 16:24 173K; 4uA; ps6=200.
    1900 17:05 - 17:34 130K; 8uA; ps6=2600.
    1901 17:36 - 17:50 400K; Test run with all auxiliary channels switched off except channel #20; 8uA, ps6=2600.
    1902 17:51 - 18:05 400K; repeat of the previous run.
    1903 18:06 - 18:18 400k; repeat of the previous run

    ---------------------------------------------
    1904 - 1906 Test runs on cosmic signals in the hall.

    1907 - 1909 More test runs, switching
    1910 Test run with all auxiliary channels off except #33 (it has a signal going to the second floor of the counting house). ps6=10, all others prescaled away.
    1911 Auxilary on and E-plane OFF except E16, ps6=12, the rest prescaled away.

    1912 ps6=320; all others prescaled away.
    ----------------------------------------------
    Back to production physics data.

    1913 22:36 - 23:36 200K; Tilted 12C target; ps1=20; ps2=2; ps3=3; ps4=12; ps5=1; ps6=9000; ps7=99999; ps8=99999.
    1914 23:38 - 00:30 200K; ps1=17; ps3=2. All other parameters are the same.