View source for Fall 2016 LHRS optic plans

==== Step L1: Procedure with Sieve-slit ====
* Time estimate: 1 hour

 * Trained personnel will be required to install the 1-inch tungsten sieve-slit collimator onto the front face of the HRS.
 * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
 * Take sieve-slit runs with the multi-foil carbon target (optics) for the inelastic kinematics in the table.
 * Electron rates assume 9 carbon foils, only 37 out of 155 sieve holes per foil have events (~ 0.41 mSr acceptance), and 8% delta acceptance.
 * Electron rates assume 15 cm LH2 target, only 45 out of 155 sieve holes have events (~ 0.49 mSr acceptance), and 8% delta acceptance.
 * <b>Adjust the prescale factors to keep the DAQ deadtime below 10%</b>.
 * <b>Before moving on to the next target, a GMp expert will determine online how many good electron events have been collected. </b>
<table border="1"  style="width:80%">
  <tr>
    <td>Target</td>
    <td>E<SUB>beam</SUB> [GeV]</td>
    <td>P<sub>0</sub> [GeV/c]</td>
    <td>Raster</td>
    <td>&theta;<SUB>e</SUB> [deg]</td>
    <td>Q<SUP>2</SUP> [GeV<SUP>2</SUP>]</td>
    <td>W [GeV]</td>
    <td> Rate [Hz] at 60 &mu;A</td>
    <td> minutes at 60 &mu;A</td>
    <td> Good Electrons</td>
  </tr>
  <tr>
    <td>Optics</td>
    <td>2.217</td>
    <td>1.0</td>
    <td><b>Off</b></td>
    <td>17.5</td>
    <td>0.20</td>
    <td>1.72</td>
    <td>540</td>
    <td>32</td> 
    <td>1M events</td>
  </tr>
  <tr>	
    <td>15 cm LH2</td>
    <td>2.217</td>	
    <td>1.0</td>	
    <td>3x3 mm<sup>2</sup></td>
    <td>17.5</td>	
    <td>0.20</td>	
    <td>1.72</td>	
    <td>4600</td>	
    <td>10.0</td>	
    <td>2.7M events</td>	
  </tr>
</table>
<br>

==== Step L2: Delta Scan with Proton Elastic (with sieve slit)====
* Time estimate: 1.5 hours

 * Keep the 1-inch tungsten sieve-slit collimator on the front face of the left HRS.
 * Take runs with the 15 cm liquid hydrogen target for the elastic kinematics in the table.
 * Wait until the left dipole reaches the desired momentum and is stable.
 * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
 * Rate estimates only include elastic electrons and does not include rate from inelastic events or from the target endcaps.
 * <b>Adjust the prescale factors to keep the DAQ deadtime below 10%</b>.
 * The Q<sup>2</sup> for these settings is 0.41 GeV<sup>2</sup>.

<table border="1"  style="width:80%">
  <tr>
    <td>E<SUB>beam</SUB> (GeV)</td>
    <td>k' (GeV)</td> 
    <td>LQ1 (A)</td> 
    <td>Raster</td>
    <td>&theta;<SUB>e</SUB> (deg)</td>
    <td>&Delta;P (%)</td>
    <td>Rate [Hz] at 10 &mu;A</td>
    <td>minutes at 10 &mu;A</td>
    <td>Good Electrons</td>
  </tr>
  <tr>
    <td>2.217</td>
    <td>2.078</td>
    <td>433.45</td>
    <td>3x3 mm<sup>2</sup></td>
    <td>17.5</td>
    <td>-4</td>
    <td>10,000 (2500 Hz with ps = 4) </td>
    <td>10</td>
    <td>1M events</td>
  </tr>
  <tr>
    <td>2.217</td>
    <td>2.038</td> 
    <td>425.11</td>
    <td>3x3 mm<sup>2</sup></td>
    <td>17.5</td>
    <td>-2</td>
    <td>10,000 (2500 Hz with ps = 4)</td>
    <td>10</td>
    <td>1M events</td>
  </tr>
  <tr>
    <td>2.217</td>
    <td>1.998</td> 
    <td>416.76</td>
    <td>3x3 mm<sup>2</sup></td>
    <td>17.5</td>
    <td>0</td>
    <td>10,000 (2500 Hz with ps = 4)</td>
    <td>10</td>
    <td>1M events</td>
  </tr>
  <tr>
    <td>2.217</td>
    <td>1.958</td> 
    <td>408.42</td>
    <td>3x3 mm<sup>2</sup></td>
    <td>17.5</td>
    <td>+2</td>
    <td>10,000 (2500 Hz with ps = 4)</td>
    <td>10</td>
    <td>1M events</td>
  </tr>
  <tr>
    <td>2.217</td>
    <td>1.918</td>  
    <td>400.08</td>
    <td>3x3 mm<sup>2</sup></td>
    <td>17.5</td>
    <td>+4</td>
    <td>10,000 (2500 Hz with ps = 4)</td>
    <td>10</td>
    <td>1M events</td>
  </tr>
</table>
<br>

==== Step L3: Dummy Target Runs ====

* Go back to the &Delta;P = 0% elastic setting. Make sure the L-HRS P0 = 1.998 GeV.
* Move the target to "15 cm Dummy"
* Take L-HRS run with same setting as previous step.
* Take data with this setting for 10 minutes
<br>
<table border="1"  style="width:80%">
 <tr>
    <td>E<SUB>beam</SUB> (GeV)</td>
    <td>k' (GeV)</td> 
    <td>LQ1 (A)</td>
     <td>Raster</td> 
    <td>&theta;<SUB>e</SUB> (deg)</td>
    <td>&Delta;P (%)</td>
    <td>Rate [Hz] at 10 &mu;A</td>
    <td>minutes at 10 &mu;A</td>
    <td>Good Electrons</td>
  </tr>
 <tr>
    <td>2.217</td>
    <td>1.998</td> 
    <td>416.76</td>
    <td>2 x 2 mm<sup>2</sup></td>
    <td>17.5</td>
    <td>0</td>
    <td>460</td>
    <td>10</td>
    <td>270k events</td>
  </tr>
</table>

<br>

==== Step L4: Proton Elastic Kinematics ====
* Time estimate: 1 hour

 * <b>Trained personnel will be required to remove the 1-inch tungsten sieve-slit collimator from the front face of the HRS</b>.
 * <b>Hall A Technical staff will need to move the left HRS from 17.5 degrees to 42 degrees</b>.
 * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
 * Elastic electron rates assume 15 &mu;A on 15 cm LH2 target, 5 mSr acceptance.
 * Use the following prescale factors: ps1=1, ps2=1, ps3=1, ps8=100. All other triggers should have zero prescale factor.
 * The 15 cm dummy and carbon pointing runs need to be taken at the elastic setting.  So keep the momentum as is. 
 * <b>A GMp expert will check the data quality.</b>

<table border="1"  style="width:80%">
  <tr>	
    <td>Target</td>
    <td>Raster</td>
    <td>E<SUB>beam</SUB> [GeV]</td>	
    <td>P<sub>0</sub> [GeV/c]</td>	
    <td>&theta;<SUB>e</SUB> [deg]</td>	
    <td>Q<SUP>2</SUP> [GeV<SUP>2</SUP>]</td>	
    <td> Electron Rate [Hz] at 60 &mu;A</td>
    <td><b>Minutes</b> at 60 &mu;A</td>
  </tr>	
  <tr>	
    <td>15 cm LH2</td>
    <td>2 x 2 mm<sup>2</sup></td>
    <td>2.217</td>	
    <td>1.366</td>	
    <td>42.0</td>	
    <td>1.57</td>	
    <td>1700</td>	
    <td>10 (for 1M events)</td>	
  </tr>	
 <tr>	
    <td>15 cm Dummy</td>
   <td>2 x 2 mm<sup>2</sup></td>
    <td>2.217</td>	
    <td>1.366</td>	
    <td>42.0</td>	
    <td>1.57</td>	
    <td>55 at 40 &mu;A</td>	
    <td>35 (115k events) </td>	
  </tr>	
  <tr>	
    <td>Single Carbon</td>
    <td>Off</td>
    <td>2.217</td>	
    <td>1.366</td>	
    <td>42.0</td>	
    <td>1.57</td>	
    <td>200</td>	
    <td>10 (for 120k events)</td>	
  </tr>	
</table>
<br>