View source for Spectrometer Optics 2014

==== Procedure with Sieve-slit ====
* Time estimate: 2-3 hours

 * A Hall A Tech may be required to install the 2-inch lead sieve-slit collimator onto the front face of the HRS.
 * Take a sieve slit run with the multi-foil carbon target for the inelastic kinematics in the table.
 * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
 * Repeat the above with the beam position shifted so that you see a vertical shift by one row.
 * Rates assume 5 carbon foils, only 9 out of 25 sieve holes have events (~ 0.146 mSr acceptance), and 9% delta acceptance.

<table border="1"  style="width:80%">
  <tr>
    <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>W [GeV]</td>
    <td> Rate [Hz] at 20 &mu;A</td>
    <td> minutes for 100k events at 20 &mu;A</td>
  </tr>
  <tr>
    <td>7.3</td>
    <td>3.056</td> 
    <td>19</td>
    <td>2.4</td>
    <td>2533</td>
    <td>16</td>
    <td>105</td>
  </tr>
  <tr>
    <td>7.3</td>
    <td>2.019</td> 
    <td>19</td>
    <td>1.6</td>
    <td>3030</td>
    <td>24</td>
    <td>70</td>
  </tr>
</table>

 <b>Alternative rates with 1-inch tungsten sieve slit: </b>
 * 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.
 * Rates assume 5 carbon foils and 9% delta acceptance.
<table border="1"  style="width:80%">
  <tr>
    <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>W [GeV]</td>
    <td> Rate [Hz] at 20 &mu;A</td>
    <td> minutes for 100k events at 20 &mu;A</td>
  </tr>
  <tr>
    <td>7.3</td>
    <td>2.918</td> 
    <td>22.8</td>
    <td>2.33</td>
    <td>2403</td>
    <td>20</td>
    <td>85</td>
  </tr>
</table>

==== Procedure without Sieve-slit ====

* Next take a run at the following kinematics without the sieve-slit collimator.	
* If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
* Rates assume 5 carbon foils, 6 mSr acceptance, and 9% delta acceptance.<br>

<table border="1"  style="width:80%">
  <tr>	
    <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>W [GeV]</td>	
    <td> Rate [Hz] at 20 &mu;A</td>
    <td> minutes for 200k events at 20 &mu;A</td>
  </tr>	
  <tr>	
    <td>7.3</td>	
    <td>2.918</td>	
    <td>22.8</td>	
    <td>2.33</td>	
    <td>2403</td>	
    <td>230</td>	
    <td>15</td>	
  </tr>	
</table>

==== Elastic from Hydrogen ====

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>
<table border="1"  style="width:80%">
  <tr>
    <td>E<SUB>beam</SUB> (GeV)</td>
    <td>k' (GeV)</td> 
    <td>&theta;<SUB>e</SUB> (deg)</td>
    <td>Q<SUP>2</SUP> (GeV<SUP>2</SUP>)</td>
    <td> Rate [Hz] at 20 &mu;A</td>
     <td> minutes for 5.4k events at 20 &mu;A</td>
  </tr>
 <tr>
    <td>7.3</td>
    <td>3.2</td> 
    <td>33.4</td>
    <td>7.7</td>
    <td>1.5</td>
    <td>60</td>
  </tr>
  <tr>
    <td>5.5</td>
    <td>3.2</td> 
    <td>28.7</td>
    <td>4.3</td>
    <td>15</td>
    <td> 6</td>
  </tr>
</table>