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Also, as we were discussing in the counting room, the sampling fraction of the calorimeter is ~0.8 - 0.85% which the plot shown doesn’t account for…so this is a big chunk of the discrepency.
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<div>On Dec 13, 2014, at 7:40 PM, Valery Kubarovsky <<a href="mailto:vpk@jlab.org">vpk@jlab.org</a>> wrote:</div>
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<div dir="ltr">Hi Volker,
<div>As Ben pointed me out the <span style="font-size:13px">clusters on the perimeter (and near the beam pipe) effectively have 6 crystals in the window instead of 3x3=9. </span></div>
<div><span style="font-size:13px">Clusters on the corners have 4 crystals in their window.</span> The majority of the clusters are near the beam pipe..</div>
<div>So the leakage may be upto 50% of the total energy.</div>
<div>Valery</div>
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<div class="gmail_quote">On Sat, Dec 13, 2014 at 2:14 PM, burkert <span dir="ltr">
<<a href="mailto:burkert@jlab.org" target="_blank">burkert@jlab.org</a>></span> wrote:<br>
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Hi all,<br>
Congratulations to starting the real data taking!<br>
<br>
I have a question on the single cluster energy spectrum. I would expect<br>
that single clusters at forward angles should have a peak at nearly the<br>
full beam energy from quasi-elastic ep scattering minus the platinum<br>
binding energy, and at very-very forward angles from e-PT -> e-PT<br>
elastic scattering. The peak sits however at much lower energy , which<br>
may indicate incorrect energy calibration, or the energy in the cluster<br>
is not completely summed up.<br>
My question is, how many crystals are summed up to define an energy<br>
"cluster"?<br>
<br>
Volker<br>
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On 12/13/14, 11:05 AM, Maurik Holtrop wrote:<br>
> Hello Takashi, Stepan and all of you on shift,<br>
><br>
> This is really great!<br>
><br>
> I went through the logbook entries and don't see the entry that explains what the source of background was and how it was eliminated. If you have a moment, could you please point me to the right entry? Was it beam-gas interactions?<br>
><br>
> Best,<br>
> Maurik<br>
><br>
><br>
> On Dec 12, 2014, at 8:39 PM, Maruyama, Takashi <<a href="mailto:tvm@slac.stanford.edu">tvm@slac.stanford.edu</a>> wrote:<br>
><br>
>> With heroic effort by Stepan, the anomalous source of background was identified and eliminated completely. 1.5 micron-thick Pt target was inserted. Attached is a ECal single rate map at 10 nA. This is very similar to what you see in Monte Carlo.<br>
>><br>
>> Ben has setup a very loose two cluster trigger and Sergey's DAQ system is taking data at 4.5 kHz at 10 nA. This data will be used to find optimum cuts for pair trigger.<br>
>><br>
>> Takashi<br>
>> RC <fadc_firsttarget.png>_______________________________________________<br>
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