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Tests of ECAL modules with LED induced light and cosmics. Ondřej Svoboda for th e ECAL group. HADES c ollaboration meeting XXV , 19 – 23 November 2012 GSI. Summary of ECAL test setup development since last collaboration meeting:
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Tests of ECALmodules with LED induced light and cosmics Ondřej Svoboda for theECALgroup HADEScollaboration meeting XXV, 19 – 23 November 2012 GSI
Summary of ECALtest setup development since last collaboration meeting: • continuous delivery of new 3 inch photomultipliers (Hamamatsu R6091) • new mounting construction designed, manufactured and tested • prototype of HV divider for R6091 photomultipliers constructed and tested • one module with optical fiber and LED diode assembled and successfully tested (8/2012) • based on this 5 modules with 1.5 inchEMI 9903KB photomultipliers and 5 modules with 3 inchR6091 photomultipliersassembled, all with optical fiber • light guide system to drive all 10 modules with one diode assembled • tests of new TRB based Front-End – see talk of BehruzKardan • first test of 3 inch photomultipliers – Yuri Sobolev
Layout of HV divider for 3 inch photomultipliers (Hamamatsu R6091) Produced by CPM Jičín, CZ • Reason for development and manufacture of own HV divider is the price of original ones… • First tests show that the divider is comparable with the original Hamamatsu divider (same current, comparable pulse shape and amplitude from the detector). • To confirm this further tests are needed and will be done in close future.
New housing for R6091 3inch photomultipliers Magnetic shielding produced in IP Bratislava
Cosmics measurement 1.5 inchphotomultiplier (EMI 9903KB) 3 inch photomultiplier(Hamamatsu R6091) ADC (channels) Energy resolution: 5.9% (best case up to now) Energy resolution: 5.4 % (best case) For measurement used CAMDA system and shaper MA8000
Tests of diodes for stability monitoring of the ECALmodules • Continuous search for optimal solution from many possibilities: • one diode per module, coupled to lead glass via optical Si fiber (20 cm) • different light output from each diode (+-50%) • one diode per sector, light guides to each module • how to distribute the light homogenously to each module? • which fibers, connectors will be used (question of price)? • light source to “power” all sector • - common diode will be most probably weak • - high power diode needs higher voltage and current – hard for 10 ns pulses • - laser sources – up to now tested one for single mode fibers • red light (not ideal for photomultiplier) • slow (not able to produce 10 ns pulse of the same amplitude) • very expensive
Light guide system for 10 modules Diode with light distribution system and 10 fibers Light output from diode Fiber to lead glass transition
Measurement with LED diode -very fast measurement (kHz) in comparison with cosmics (~1 signal /3 minutes) - signal from pulser set to get the same detector response as from cosmics 3 inch photomultiplier (Hamamatsu R6091) Yellow curve – detector output Green curve – diode input (second peak is reflection on diode) after Front-end board 1.5 inch photomultiplier (EMI 9903KB)
Measurement with LED diode and 3 inch photomultiplier Hamamatsu R6091 Measurements made by Y. Sobolev on CAMDA system
Summary: • - LED can be used for regular stability monitoring of ECALduring beamtime • - basic assembly of ECALmodule driven by LED diode successfully tested • - search for final LED system design • - new housing for R6091 3inch detectors • - first tests of own HV dividers for R6091 3 inch photomultipliers • - tests of ECALmodules with both types of PMT‘s on cosmics and with LED diode performed