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Status report SiPMs production for the testbeam prototype MEPhI and Pulsar, Moscow. CALICE technical review, DESY, February 25, 2005. DESY ordered 5000 SiPMs on precision plates for installation in prototype.
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Status reportSiPMs production for the testbeam prototypeMEPhI and Pulsar, Moscow CALICE technical review, DESY, February 25, 2005
DESY ordered 5000 SiPMs on precision plates for installation in prototype. • Not less then 4000 from such amount should be selected as “good” (80% from total amount).
SiPM production CALICE technical review, DESY, February 25, 2005
2M 20M SiPMs modifications CALICE technical review, DESY, February 25, 2005
840 pcwere transferred to ITEP • 504 with 2M • 282 with 20M See ITEP talk : similar characteristicsfor both types SiPMs exceptgain It is important : 20M in average that means R=(2010)M (from measurements of the test structures on uncutted wafer) Results: 712 pcwere accepted 84.7% yield CALICE technical review, DESY, February 25, 2005
Advantages of 20M quenching resistor: • No dependence of the pixel gain on quenching resistor value (better single pixel resolution, better temperature gain stability). • More safe quenching. • No dependence of saturation curve on calibration light pulse form. • Uniform prototype because SiPMs with resistors from 10M to 30M are indistinguishable. CALICE technical review, DESY, February 25, 2005
Production schedule CALICE technical review, DESY, February 25, 2005
Possible problems Problems with precision plates for SiPMs mounting • Pins on plate fixation some time too weak - under improvement now • Accuracy of the dimensions – maybe the way of plate in tile installation should be changed (gluing) • Production yield Long term stability of the SiPMs should be checked more carefully with larger statistics – if we glue SiPMs in tiles we will not be able to change them inside cassetes We should apply SiPM surface protection – high sensitivity of the SiPMs to WLS and tilemite (high possibility to kill SiPM) We don’t have order to next 5000 pc CALICE technical review, DESY, February 25, 2005
Summary 1.Production rate of scintillators and fibers are consistent with our schedule. 2.Test bench for SiPM selection is operational. 3.Automatic test bench for assembled tiles quality control is on set up stage. We expect to start with full rate in few weeks. 4.To solve foreseen difficulties with ready detectors shipment an agreement between DESY and ITEP on prototype construction will be solved soon CALICE technical review, DESY, February 25, 2005