Difference between revisions of "Commissioning Run Plan"

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<li> Angle restrictions with DVCS calorimeter in place:
 
<li> Angle restrictions with DVCS calorimeter in place:
 
<ol>
 
<ol>
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<li> HRS-BL: 26.5 to 45 degrees
+
<li> HRS-BL: 17.9 to 45 degrees
 
<li> HRS-BR: 46.2 to 74.5 degrees
 
<li> HRS-BR: 46.2 to 74.5 degrees
 
</oL>
 
</oL>
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  * Initial checks of beam position and raster.
 
  * Initial checks of beam position and raster.
  
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=== HRS Checkout (Experts) ===  
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===[[ HRS Checkout (Experts) ]]===
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The detector checkout is best done using a fairly uniform illumination, which is
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provided for by 20 &mu;A on the central Carbon target at the following kinematics:
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E' = 3.056 GeV, &theta; = 19 degrees (W<sup>2</sup> = 2.53 GeV, Q<sup>2</sup> = 2.43 GeV<sup>2</sup>).  The
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===[[ Beamline ]]===
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HRS electron rates should be about 270 Hz.
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<table border="1"  style="width:80%">
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  <tr>
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    <td>E<SUB>beam</SUB> [GeV]</td>
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    <td>P<sub>0</sub> [GeV/c]</td>
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    <td>&theta;<SUB>e</SUB> [deg]</td>
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    <td>Collimator</td>
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    <td>Target</td>
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    <td>Fast Raster <br> X x Y </td>
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    <td>Beam Current</td>
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  <td>Trigger</td>
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  </tr>
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  <tr>
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    <td>7.3</td>
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    <td>3056</td>
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    <td>19.0</td>
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    <td>None</td>
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    <td>Single Carbon</td>
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    <td>off</td>
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    <td>20&mu;A</td>
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    <td>S0&&S2m</td>
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  </tr>
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</table>
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<ol>
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<li> With the above kinematics, take a run (at least 100K events or 10 minutes) and verify that all detector channels are working.
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<li> Using the same run, produce a ROOT tree, and do the following: make a spectrum of x vs. y at the focal plane.  What you should see is a "spider" with 5 legs.  The non-straightness of the central legs indicates there is an offset in the Z or Y direction.  If you don't see a "spider" or something resembling it, then of of the polarities of the HRS magnets is set wrong (or a magnet is off).
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<li> Check that the signals are well timed.
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<li> Determine correct thresholds.
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<li> Verify all scalers are incrementing.
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<li> Check for double pulsing and time the wire chamber signals.
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<li> Are the scintillator signals for on scale in the scintillator ADCs?
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<li> PID threshold checks.
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</ol>
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=== Beamline ===
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===[[ Beamline (2014) ]]===
  
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==== Initial BPM/Raster checks/Beam centering ====
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===[[ HRS Detector Calibrations ]]===
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<ol>
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<li> First MCC centers the beam on the beam dump using the ion chambers.
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<li> Ideally the beam should be able to pass cleanly through the Compton chicane. But this is not a requirement.
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<li>Check the raster size using the spot++ tool.  After the target boiling studies result, the final raster size for production data will be decided.<br>
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<li>Insert carbon hole target to center the beam position with respect to the hole. Setup the raster to 2*2 mm, use spot++ to check if the beam is centered around the hole. Move the beam if necessary.
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</ol>
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==== Superharp Scan with Raster off/on ====
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===[[ Beam Position on Target ]]===
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<ol>
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<li> Scan the two superharps near the target with raster off.  Obtain two pictures including the three wires for each harp.
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<li> Make sure the three wires are clearly visible and have reasonable resolution: ~ 100-200 &mu;m.
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<li> Repeat with raster on.  In this case, you may not see the wires clearly.
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<li> Make sure to post the results in the Hall A electronic logbook or Halog.
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</ol>
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==== BPM Calibrations (Bullseye Scan) ====
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===[[ Spectrometer Optics ]]===
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<FONT Color="Green">How to perform a bulls eye scan</FONT>:
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1.  You need unrastered beam:
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===[[ Spectrometer Optics 2014 ]]===
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    - <FONT Color="red">caution you should not do this with a target requiring rastered beam</FONT>
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    - use carbon, BeO, optics, or in the worst case empty instead
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2.  Ask MCC to steer the beam to the nominal center of the target.
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=== [[ Luminosity Scans - Low Rate (Target Boiling) ]]===
  
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3.  Wait until beam is stable and have MCC perform a harp scan for the two superharps near the target (1H03A and 1H03B) and take a coda run during the 
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=== [[ Initial HRS Elastic Checks ]]===
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    same time. Start the coda run first before asking MCC.  Request MCC to make an ELOG entry with the results, you should see all three harp wires.
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    Record ELOG entry numbers.
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4.  Ask MCC then to steer the beam to positions around the nominal center:
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    - cover at least the area the raster will cover: (2,2), (2,-2), (-2,-2), (-2,2) and repeat (0,0)
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    - repeat harp and coda runs for each position
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5.  Record Harp scan run numbers and corresponding CODA run number for each beam position.
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6.  Make a record of the harp scans and CODA runs in the HAlog.
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<FONT Color="Green">How to analyze the bulls eye scan</FONT>:
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  - detailed instructions can be found at the [http://hallaweb.jlab.org/root/doc/bpm.html Analyzing BPMs] website.
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  - <FONT Color="red">the shift crew is not expected to analysis the bulls eye scan</FONT>.
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==== BCM Calibrations [2 hours] ====
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<ol>
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<li> Warn MCC a few hours beforehand.
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<li> The Hall A BCM and scalers need to be cross-calibrated to the Faraday cup and a BCM in the accelerator (OLO2) and the Hall A Unser.
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<li> Before beginning the procedure, make sure the Hall A BCM logger is started, which will record the signals from all relevant BCM used during the calibration.
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<li> Also start a HRS run to record the scalers during the calibration procedure.
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<li> It is useful to have someone over in MCC to help coordinate the calibration with them.
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<li> Take data on carbon target with I = 10, 20, 30, 40 50, 60, 70, 80, 90, 100 &mu;A (or as high a current as available).
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</ol>
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==== ARC Energy Measurement [? hours] ====
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<ol>
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<li> The procedure will be conducted by Doug Higinbotham in coordination with MCC.
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<li> Notify Doug and MCC a few hours beforehand to make sure they are ready and available.
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</ol>
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=== Spectrometer Optics ===
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* Time estimate: 1-2 hours
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==== Procedure with Sieve-slit ====
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* A Hall A Tech may be required to install the 2-inch lead sieve-slit collimator onto the front face of the HRS.
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* Take a sieve slit run with the multi-foil carbon target for the inelastic kinematics in the table.
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* If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
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* Repeat the above with the beam position shifted so that you see a vertical shift by one row.
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* Rates assume 5 carbon foils, only 9 out of 25 sieve holes have events (~ 0.146 mSr acceptance), and 9% delta acceptance.
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<table border="1"  style="width:80%">
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  <tr>
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    <td>E<SUB>beam</SUB> [GeV]</td>
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    <td>P<sub>0</sub> [GeV/c]</td>
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    <td>&theta;<SUB>e</SUB> [deg]</td>
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    <td>Q<SUP>2</SUP> [GeV<SUP>2</SUP>]</td>
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    <td>W [GeV]</td>
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    <td> Rate [Hz] at 20 &mu;A</td>
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    <td> minutes for 100k events at 20 &mu;A</td>
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  </tr>
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  <tr>
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    <td>7.3</td>
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    <td>3200</td>
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    <td>19.0</td>
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    <td>2.5</td>
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    <td>2455</td>
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    <td>15</td>
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    <td>110</td>
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  </tr>
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  <tr>
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    <td>7.3</td>
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    <td>2019</td>
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    <td>19.0</td>
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    <td>1.6</td>
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    <td>3030</td>
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    <td>24</td>
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    <td>70</td>
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  </tr>
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</table>
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<b>Alternative rates with 1-inch tungsten sieve slit: </b>
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* Assumes that 49 out of the 63 holes are seen (~ 0.52 mSr acceptance); however, the acceptance is reduced by 85%, <br>  since not all foils will see all holes.
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* Rates assume 5 carbon foils and 9% delta acceptance.
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<table border="1"  style="width:80%">
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  <tr>
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    <td>E<SUB>beam</SUB> [GeV]</td>
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    <td>P<sub>0</sub> [GeV/c]</td>
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    <td>&theta;<SUB>e</SUB> [deg]</td>
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    <td>Q<SUP>2</SUP> [GeV<SUP>2</SUP>]</td>
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    <td>W [GeV]</td>
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    <td> Rate [Hz] at 20 &mu;A</td>
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    <td> minutes for 200k events at 20 &mu;A</td>
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  </tr>
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  <tr>
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    <td>7.3</td>
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    <td>3056</td>
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    <td>19.0</td>
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    <td>2.4</td>
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    <td>2533</td>
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    <td>58</td>
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    <td>58</td>
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  </tr>
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</table>
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==== Procedure without Sieve-slit ====
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* Next take a run at the following kinematics without the sieve-slit collimator.
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* If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
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* Rates assume 5 carbon foils, 6 mSr acceptance, and 9% delta acceptance.
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<table border="1"  style="width:80%">
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  <tr>
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    <td>E<SUB>beam</SUB> [GeV]</td>
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    <td>P<sub>0</sub> [GeV/c]</td>
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    <td>&theta;<SUB>e</SUB> [deg]</td>
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    <td>Q<SUP>2</SUP> [GeV<SUP>2</SUP>]</td>
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    <td>W [GeV]</td>
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    <td> Rate [Hz] at 20 &mu;A</td>
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    <td> minutes for 400k events at 20 &mu;A</td>
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  </tr>
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  <tr>
+
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    <td>7.3</td>
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    <td>3200</td>
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    <td>19.0</td>
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    <td>2.5</td>
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−
    <td>2455</td>
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−
    <td>623</td>
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    <td>11</td>
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  </tr>
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−
  <tr>
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    <td>7.3</td>
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    <td>2019</td>
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    <td>19.0</td>
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    <td>1.6</td>
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    <td>3030</td>
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    <td>975</td>
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    <td>7</td>
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  </tr>
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</table>
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==== Elastic from Hydrogen ====
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Elastic electron-proton measurement.  Assuming a 15 cm LH2 target, a spectrometer acceptance of 6 msr and elastic from Eric's rate program to compute the cross-section.  Taking data at 7.3 GeV with the given momentum restrictions is time consuming.<br> (Table borrowed from DVCS3 wiki page)<br>
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<table border="1"  style="width:80%">
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  <tr>
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    <td>E<SUB>beam</SUB> (GeV)</td>
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    <td>k' (GeV)</td>
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    <td>&theta;<SUB>e</SUB> (deg)</td>
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    <td>Q<SUP>2</SUP> (GeV<SUP>2</SUP>)</td>
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    <td> Rate [Hz] at 20 &mu;A</td>
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    <td> minutes for 5.4k events at 20& mu;A</td>
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  </tr>
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−
<tr>
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    <td>7.3</td>
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    <td>3.2</td>
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    <td>33.4</td>
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    <td>7.7</td>
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    <td>1.5</td>
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    <td>60</td>
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  </tr>
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−
  <tr>
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    <td>5.5</td>
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    <td>3.2</td>
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    <td>28.7</td>
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    <td>4.3</td>
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    <td>15</td>
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    <td> 6</td>
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  </tr>
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</table>
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−
 
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=== Luminosity Scans - Low Rate (Target Boiling) ===
+

Latest revision as of 22:14, 18 April 2015

For the Fall of 2014 assume:

  • Maximum beam current = 20 μA but for short times it can go higher for boiling studies and BCM calibration.
  • 7.3 GeV @ 4 pass, 5.5GeV @ 3 Pass and 3.7 GeV @ 2 pass. No five pass beam in the Fall of 2014.
  • Angle restrictions with DVCS calorimeter in place:
    1. HRS-BL: 17.9 to 45 degrees
    2. HRS-BR: 46.2 to 74.5 degrees

Pre-beam Checklist

Trigger Checkout (Experts) 

* Checkout trigger timing
* Checkout of EDTM (Barak Schmookler)
* Think about adding 60, 100, 150, and 200 ns wide electronic deadtime scalers.
  This has been found to be a robust method for determining electronic deadtime in Hall C and we should think about adding something similar for GMP.

HRS Detector Checkout (Detector Experts) 

* Take a long cosmics run with all detectors on.
* Look for dead and hot wires in the wire chambers against an earlier plot to look for any possible inconsistencies in wiring.  Check these against 
  those listed in the current analysis parameters. (Yang Wang)
* Look at ADC distributions for the hodoscopes Gas Cherenkovs and lead glass calorimeters.  Are they all firing? (Barak Schmookler, Longwu Ou)
* Look at TDC distributions for hodoscopes and Gas Cherenkovs.  Is the timing reasonable, any multiple peaks, within timing range, etc? 
  (Barak Schmookler, Longwu Ou)

Commissioning and Calibrations

The following items should be performed during the first 1-1.5 shifts with beam on target: 

* Initial trigger checkout with beam.  Check timing and PID thresholds.
* Initial detector checkout with beam.
* Initial checks of beam position and raster.

HRS Checkout (Experts)

Beamline

Beamline (2014)

HRS Detector Calibrations

Beam Position on Target

Spectrometer Optics

Spectrometer Optics 2014

Luminosity Scans - Low Rate (Target Boiling)

Initial HRS Elastic Checks

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