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CALO maintenance overview. ECAL LED monitoring system replacement. commissioning : Broken fibers (repaired): 3 at side C, 4 at side A 3 cells at the side A have no signal, q. fibers are OK, need access to PMTs (dead CW or contact problem), next week
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CALO maintenance overview Yu. Guz 2014/05/21
ECAL LED monitoring system replacement • commissioning: • Broken fibers (repaired): 3 at side C, 4 at side A • 3 cells at the side A have no signal, q. fibers are OK, need access to PMTs (dead CW or contact problem), next week • contact problems at the FEB side: few at the side A, much worse at the side C (next slide) • TODO: • General commissioning • Carefully fix contacts at the FEB end (in progress) and PMT end: • one more access to PMTs side C may be needed later • Tune: • LEDTSB timing • PIN amplitudes: mechanical arrangement of PIN fibers, voltage dividers for signal • PIN FEB timing Yu. Guz 2014/05/21
ECAL commissioning • Fixing loose contacts (a source of instabilities), both at the FEB side and at the PMT side • Side C for the moment, fixed by now: • ~80 ATI connectors (FEB end) • ~40 BERG connectors (PMT side) • more expected … • Side A next week: • less problems expected with ATI • few loose BERG connectors (PMT side)seen with the reflection test, few days access to PMTs is foreseen ATI connectors side C (crimped in 2006) Yu. Guz 2014/05/21
HCAL PMT degradation • Helium test performed (Pavel) • the good (stable) and bad PMTs degrade with equal speed • the reason of degradation of PMTs at HCAL is not understood good PMT bad PMT Yu. Guz 2014/05/21
HCAL maintenance and plans • maintenance of both garages of the source calibration system (replacement of a rubber membrane) performed • PMT replacement at the side A • 49 new PMTs have to be installed • planned after the ECAL access • for the moment: preparing new PMTs for replacement • new HCAL CW boards are being produced (40) Yu. Guz 2014/05/21
AOB Blue light (460 nm) • another irradiation test of quartz fibers at UKL (Louvain-la-Neuve) is planned for beginning of July. This time the purpose is: • measurement of the depth of fast degradation/annealing cycles as a function of dose rate, using the sample already irradiated in 2013 • measurement of the wavelength dependence of degradation 825 krad 100 krad 300 krad 530 krad Yu. Guz 2014/05/21