<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body >Those plots are fron the trigger hardware. Like Kyle mentioned these are 3x3 windows for the sum c but currently we only sum hits that within +/-12ns of the highest energy hit. Pulse times are not time walk corrected, so this likely is playing a role in lowering the plot energy.<div></div><div><br></div><div>An offline analysis should show a higher energy and would be an interesting comparison.</div><div><br></div><div>Ben</div><br><br>-------- Original message --------<br>From: burkert <burkert@jlab.org> <br>Date:12/13/2014 2:14 PM (GMT-05:00) <br>To: hps@jlab.org <br>Cc: <br>Subject: Re: [Hps] HPS is taking data <br><br>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><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 <tvm@slac.stanford.edu> 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>>> Hps mailing list<br>>> Hps@jlab.org<br>>> https://mailman.jlab.org/mailman/listinfo/hps<br>><br>> _______________________________________________<br>> Hps mailing list<br>> Hps@jlab.org<br>> https://mailman.jlab.org/mailman/listinfo/hps<br><br>_______________________________________________<br>Hps mailing list<br>Hps@jlab.org<br>https://mailman.jlab.org/mailman/listinfo/hps<br></body>