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Status of ECAL integrators. Integrator boards. New version (install a 100 nF blocking capacitor in the fast signal line): uses ~90% of the anode current, instead of ~1% sensitivity ~ 100 DCU counts/ μ A DC gain ~2.2 instead of 3000 no stability problems with TL072 ( rad hard).
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Integrator boards • New version (install a 100 nF blocking capacitor in the fast signal line): • uses ~90% of the anode current, instead of ~1% • sensitivity ~ 100 DCU counts/μA • DC gain ~2.2 instead of 3000 no stability problems with TL072 (rad hard) I, nA NB requires slight modification of CW bases: install 100 nF in series with 25 Ω. This does not affect the signal. Recently, the integrators were upgraded: the 40 mezzanines were replaced with new ones. The work on production and installation of new integrator boards, including modification of host CW bases, was performed in December 2010 – January 2011 (Irina, Pavel, Anatoly Zh.). The nominal sensitivity is 275 mV/μA (110 counts/μA). Measured at the lab before installation in 20 out of 40 boards (Pavel): ±2% deviation. When installed onto CWs, its sensitivity becomes 100 counts/μA because of the 100kΩ “safety” resistor at the CW base. The anode current in ECAL is measured in 40 PMTs out of 6016, through “integrators”, 1-channel mezzanine boards installed at the back of each of these 40 PMT/CWs (original design by Yu. Gilitsky). Each integrator contains an amplifier for measuring current and pass-through for fast signal and LV/MV. The readout is performed via SPECS DCU of regular CALO DAC/HV motherboards. Part of ECAL HV projects. Yu. Guz
Integrator readout Within the monitoring script of the ECHVA1/ECHVC1 projects, every ~25 sec. PVSS archiving is arranged for all the 40 channels. Trending pages are available (use shortcut G:\online\ecs\Shortcuts38\LHCb\LBECSINFO\LBECSINFO_UI_lbTrending , then CALO ECAL IntegratorsA or IntegratorsC). By unknown reason (presumably hardware SPECS problem, to be understood), at the C side the regular readout with SPECS server fails. To cope with this, a software patch is applied: the integrators are read out with a separate executables controlled by ECAL HV projects. The result returned into the PVSS projects is an average over several consecutive measurements (22-23 readings, limited to 1 sec), this is to reduce fluctuations expected at beam. Will return to regular readout when (if) the problem at side C will be understood. To ensure reliability, the information is also stored locally in .txt files. L:\pvss\ECAL_INTdata\data\Ecal_INTdata_A.txt (EcalINTdata_C.txt) on ECHVA01W (ECHVC01W). Yu. Guz