, Forward Endcap News Thomas Held Ruhr-Universität Bochum Institut für Experimentalphysik I LII. PANDA Collaboration Meeting, Giessen March 17th, 2015 Thomas Held (RUB EPI) Forward Endcap News
, Miscellaneous Topics Broken APD couplings (Proto192) HV modules: Iseg-Meeting Cable routing in forward endcap VPTTs Support and mounting frame (Jülich) Thomas Held (RUB EPI) Forward Endcap News
, Proto192: Broken APD Couplings Reported at Jülich meeting: APD-pairs on the same crystal show different light yields Further investigation: Dismantling of APD-subunit Result: Broken couplings to some of the crystals Three units fallen off completely Thomas Held (RUB EPI) Forward Endcap News
, Proto192: Broken APD Couplings VPTT subunit totally unaffected: rock-solid couplings Most likely scenario: insufficient curing time (stress on coupling (mounting) during curing) Curing by reaction with air moisture - penetration through complete coupling necessary VPTTs glued one month, APDs glued three days before beam time... However, bad couplings not correlated with differing light yields APD yield measurements to better understand/explain the differences in crystal readout Thomas Held (RUB EPI) Forward Endcap News
, HV modules: Iseg-Meeting Problems with ISEG HV modules (APD lab and Bochum) Negative currents/zero load currents, waiting time per voltage step There is a minimum latency to account for in order to get precise current values for a choosen voltage setting (depends on module firmware - up tp 40 s) Allow for non-zero open loop currents: record and subtract (intrinsic current does not change with load) All these effects are covered by the stated accuracy given in the manual χ χ iseg Module GSI Channel 0 30s 2 2 / ndf / ndf 1.117e-07 / 447 1.117e-07 / 447 ± ± p0 p0 -0.0009262 -0.0009262 1.495e-06 1.495e-06 Current / muA -0.0009 p1 p1 -1.319e-06 -1.319e-06 ± ± 5.756e-09 5.756e-09 -0.001 -0.0011 χ χ χ χ iseg Module 2 Channel 0 open 2 2 / ndf / ndf 6.053e-05 / 447 6.053e-05 / 447 iseg Module 2 Channel 0 open / ndf 2 / ndf 2 1.43e-07 / 447 1.43e-07 / 447 ± ± ± ± -0.0012 p0 p0 0.001406 0.001406 3.479e-05 3.479e-05 p0 p0 0.001414 0.001414 1.691e-06 1.691e-06 Current / muA ± ± Current / muA ± ± p1 p1 -4.195e-06 -4.195e-06 1.34e-07 1.34e-07 p1 p1 -4.136e-06 -4.136e-06 6.513e-09 6.513e-09 0.0025 0.0015 -0.0013 0.002 0.0015 0.001 0.001 -0.0014 0.0005 0.0005 0 -0.0015 0 -0.0005 -0.001 0 50 100 150 200 250 300 350 400 450 -0.0005 Voltage / V 0 50 100 150 200 250 300 350 400 450 0 50 100 150 200 250 300 350 400 450 Voltage / V Voltage / V Thomas Held (RUB EPI) Forward Endcap News
, Forward Endcap Cabling, Mechanics (Bonn) Cabling photo detector units: All signal cable: delivered HV and LV cable: order soon (talk to vendor/tailor), delivery 1-2 weeks after order GND cable: distributor located, offers requested, delivery 1-2 weeks after order Subunit patch-panel: received offers for connectors (ordering soon), U.FL connectors arrived last week Design patch-panel pcb not yet finalized: introduction of power planes for LV feeding, extension to 8 layers Thomas Held (RUB EPI) Forward Endcap News
, Forward Endcap Cabling, Mechanics (Bonn) Connection patch-panel to outside: Signal cable ordered Signal cable connection: modify pitch adapter pcb (changes because of swichover to thinner cable), talk to assembler LV: cable type still to determine HV cable: delivered (talk to tailor - mounting of Molex connectors) Molex connector: offers received, ordering soon Mechanics: Mountplates: ready Inserts: ready (except for some spares) Interface pieces: got drawings, clarify with workshop Thomas Held (RUB EPI) Forward Endcap News
, Cable routing in forward endcap Routing scheme finished Test bundle between subunits X5Y8 and X6Y8 (the biggest one: 32 HV lines, 256 singnal lines, 9 ribbon cables) fits in available space Thomas Held (RUB EPI) Forward Endcap News
, VPTTs All 900 VPTTs for PANDA delivered now! Gain measurements done so far: 564 pieces (750/1000 V) Cathode and anode dark currents ( 0.1 nA) One VPTT returned to Hamamatsu (weak connection wire) Medium gain: 54.8 (Hamamatsu), 52.7 (750V), 64.8 (1000V) All deviations (Hamamatsu vs. BO) in gain (750 V) ≤ 10 % (as always) Thomas Held (RUB EPI) Forward Endcap News
, VPTTs Forseen: Three different preamp types (gain) Medium gain version will need twice the gain the preamps have now (0.5 V/pC → 1 V/pC) Basel is currently manufacturing a version for testing Basel also modified the voltage divider PCB to 1500 V capability (works perfect) As soon as the new preamps are delivered, all VPTT subunits can be finished Thomas Held (RUB EPI) Forward Endcap News
, VPTTs Preamp gain estimations based on tube gain and magnetic field map New simulation by Yuri Lobanov: 0.95-1.04 T at tube location Still to do: tube-position assignment (with B-field measurement data from Bonn) Thomas Held (RUB EPI) Forward Endcap News
, Support and mounting frame (Jülich) Design of a support and mounting frame (Zentralinstitut für Engineering, Elektronik und Analyse, FZJ) Secure mounting/removing (maintenance) of forward endcap and disc DIRC into/out of Panda magnet Construction of a base to place the endcap in COSY beam height for the preassemly in Jülich Support frame also needed for secure transport of the detector to Darmstadt Thomas Held (RUB EPI) Forward Endcap News
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