<div dir="ltr"><div><div>Hello Volker,<br><br></div>Clusters, in the hardware at least, are defined using a 3 x 3 window around a central highest-energy hit. Essentially, the GTP clusterer finds a crystal that is a local maximum and then declares it, along with the 8 crystals around it, to be a cluster.<br><br></div>- Kyle<br></div><div class="gmail_extra"><br><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:<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">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>
<div class="HOEnZb"><div class="h5"><br>
<br>
<br>
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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