Minutes of the forward endcap EMC meeting, 1st of September 2014, SeeVogh, 14:00 - 16:00

  • Basel: Werner
  • Bochum: Claudius, Fritz-Herbert. Malte, Mario, Markus, Matthias, Patrick, Petra, Stefan, Tobias, Tom
  • Bonn: Christoph
  • Frankfurt: Florian
  • GSI: Andrea

  • Gain of APD preamp: gain depends on 1 pF capacitor. Precision +-0.2 pF. Same charge have very uniform values. However versions from two different producers soldered (white/vilolet) version. Check for gain differences for these preamp versions. Basel will check in preamplifier test database whether different rise times are observed. (Werner)
  • Ringing of APD preamp in cold (Tom). Basel and Bochum will check different options (capacitors). This will increase rise time. Question: What is allowed from the pileup detection? (Werner, Matthias)

  • Measurements at ELSA with Proto192 show variations of calibrated signals of about 20%; in addition a few channels have only 50% of the signal height. Reasons are unknown. What can we expect from APD gain calibration? (Fritz-Herbert)
  • The dark current measurements for currents below 1nA are problematic. It has to be investigated by ISEG. This gives for some APDs an error on the M=1 normalization. (Andrea). Andrea will check which APD measurements had this problem.
  • In which range is the parameterization (modified Miller function) used (Malte)? Below M=20 linear function, for about 200-450 V fit by the function.
  • Action: Andrea will send curves (data points vs. HV) of measurements at -25 and +20 degrees to Bochum.
  • Action: Bochum will send Andrea measurements of DC vs. pulsed.
  • Measurements of first 750 APDs ongoing. Measurement results will be made available asap. (Andrea)


  • "PatchPanel PCB": new selections of connectors (Christoph)
  • For tests of cable routing at 1:1 model or real backplate one will need 18 PatchPanelPCBs and Cables (Claudius). Christoph orders signal cables for tests asap and sends them to Bochum.
  • Bochum will check damping with preamp signals with ~10m cables.
  • LV cables still to be decided (Mario will check availability of shielded cables). LV distribution scheme to be decided on.
  • Claudius needs up to date NX CAD files from KVIcart for the cable routing to the ADCs.


  • Production at Bonn (Christoph):
    • Interface pcs.: One needs for the finalization a list of angles and drawings for the mounting tool holes from KVIcart.
    • Alveoli: 50 % ready
    • Mountingplate: need to check/correct hole for LP.
    • Inserts: ok.
  • Production at KVIcart (Added information from Myroslav by phone after meeting)
    • Henk will arrange the delivery of the backplate and frame to Bochum


  • New shaper: Bonn will design a 4 channel shaper module similar to the version on the newest ADC. Input UFL, output Pfostenfeldstecker. Power via VME if possible. (Christoph)
  • Mailing list had problems. So people did not receive the invitation.

-- FritzHerbertHeinsius - 02 Sep 2014
Topic revision: r2 - 2014-09-03, FritzHerbertHeinsius
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