CMS-DP-2015/063

History of ECAL response with laser data in 2015

Abstract: Update of the crystal transparency evolution in ECAL with laser data including measurements taken up to Oct., 8th 2015

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histories 2011-2012-2015 151028.png
History of relative response

Relative response to laser light (440 nm in 2011 and 447 nm from 2012 onwards) injected in the ECAL crystals, measured by the ECAL laser monitoring system, averaged over all crystals in bins of pseudorapidity, for the 2011, 2012 and 2015 data taking periods, with magnetic field at 3.8 T.
The response change observed in the ECAL channels is up to 6% in the barrel and it reaches up to 30% at η ~ 2.5, the limit of the tracker acceptance. The response change is up to 70% in the region closest to the beam pipe.
The recovery of the crystal response during the Long-Shutdown-1 period is visible, where the response was not fully recovered, particularly in the region closest to the beam pipe. These measurements are used to correct the physics data.
This is an update of the plots appearing in CMS-DP-2012/007, CMS-DP2012/015 and CMS DPS 2015-016, and includes measurements taken up to October, 08th 2015.
The bottom plot shows the instantaneous LHC luminosity delivered during this time period.

-- EmanueleDiMarco - 2015-12-16

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf histories_2011-2012-2015_151028.pdf r1 manage 3222.6 K 2015-12-16 - 10:34 UnknownUser  
PNGpng histories_2011-2012-2015_151028.png r1 manage 117.0 K 2015-12-16 - 10:34 UnknownUser  

This topic: CMSPublic > PhysicsResults > EcalDPGResults > EcalDPGResultsCMSDPS2015063
Topic revision: r1 - 2015-12-16 - unknown
 
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