Log entry time 22:43:54 on January 10, 2012

Entry number 247205

All of the studies will be done at "50 pA" (with a couple exceptions), so here are some general considerations that apply:

• HDC current: Look at the Hokie2C Imon current occasionally. I have set the trip current for the HDCs to 2500 (25 uA), but I would like to try to keep Hokie 2C in the 1500 - 2000 range (15 uA - 20 uA) generally. If it goes very far out of that range, see the instructions below for adjusting it.
• Also, we would like to keep the Hokie 2 Fast OR rates in the 85 kHz - 110 kHz range. To adjust, simply ask MCC to step the "Laser Attenuator" in steps of 1 until you get back in the desired range.
• The DAQ setup should be for "tracking" run type, Trigger scintillator prescale = 2 (for a DAQ data-taking rate that will typically be about 1700 Hz), and fake MPS rate of 10 Hz.
• Pay attention to the downstream lumi screens. If they track together, then probably just the beam current is changing. If you see the rates of opposite ones going in opposite directions, then probably the beam position is changing. The procedure for checking the beam position is below. (Note: the numbering scheme of the downstream lumis is the same as the MDs).
• For each run take 2.5 million triggers (assuming beam stays on the whole time - watch the lumi screens). This will usually take about 25 minutes. If there is a beam trip(s) for a significant time during the run, then extend the run by the correct fractional amount.
  

  Run Plan:

  1. Q2 position scan: Conditions: LH2 target, 2x2 mm^2 raster size, "50 pA" beam current (real criteria is to try to keep Hokie 2 Fast OR rate in the 85 - 110 kHz range). This plan will consist of taking Q2 runs at the "nominal" beam positions and then varying by +2,+1,-1,-2 mm from nominal for both X and Y (with the other held at nominal). The table of steerer settings needed is attached. So this will be a total of 9 runs. After each run is done, start a run (with TS prescale set to maximum - so we are only recording scalers) and start a IHA3H07B superharp scan (takes 3 minutes to run). Snapshot the scan and post it to the logbook. This study was mostly done last time. All that needs to be done this time is "nominal" and y - 1 mm and y - 2 mm. For the horizontal steerer settings, nominal (as determined tonight) is: MDB3H02H = 928 MAP3H07H = -2156 For the vertical steerer settings, nominal is: MBD3H02V=-3690 MBD3h06V=-6865

     For the x nominal, y = nominal - 1 mm setting use MBD3H02V=-3100 MBD3H06V=-6384

     For the x nominal, y = nominal - 2 mm setting use MBD3H02V=-2607 MBD3H06V=-5932

     At then end return all of them to their nominal values: MBD3H02H=928 MAP3H07H=-2156 MBD3H02V=-3690 MBD3H06V=-6865

  2. Rate Dependent Study:Conditions: LH2 target, 4x4 mm^2 raster (note change from first step), "nominal beam positions - achieved with the nominal steerer settings right above. Here the idea is to take four runs at four different Hokie 2 Fast OR settings (achieved by changing the laser attenuator. The desired settings are 80 kHz, 60 kHz, 40 kHz, and 20 kHz above the "beam off" rate. The beam off rate for Hokie 2 is 25 kHz, so you should aim for 105 kHz, 85 kHz, 65 kHz, and 45 kHz for the total Hokie 2 Fast OR rates.
  3. Q2 near Delta Peak: Conditions: LH2 target, 4x4 mm^2 raster, "nominal beam positions - achieved with the steerer settings in first row of the attached table. Here you should take three runs at different Q2 settings: QTOR = 7000 A, 6700 A, 6000 A.
  4. Solid Targets:Conditions: Do the standard "2.5 million events" for each of the solid targets specified below. Set QTOR back to 8901.9 A. Raster should be set to 1x1 mm^2 (please note this change in raster setting from above). In each case, have MCC adjust the laser attenuator to keep the Hokie 2 Fast Or rate in the 85 - 110 kHZ range. When you put in a new target (especially a thicker one) it is best to have them back off the laser attenuator, maybe 10 steps or so and then approach the desired rate from below; this will help avoid tripping off the HDCs (but if you do trip them just bring them back on after getting the beam current down).
     • 1% upstream Al
     • 2% upstream Al
     • 4% upstream Al
     • 2% downstream Al
     • 4% downstream Al
     • 8% downstream Al
     • 0.5% upstream C
     • 1.6% downstream C
  5. Q2 Stability Study: Conditions: LH2 target, 4x4 mm^2 raster (note change from above step), nominal beam positions. The idea here is to just to take multiple 25 minute (2.5 million event) runs at "constant" conditions to monitor the stability of our Q2 measurement. QTOR should be back at 8901.9 A.