Minutes of the forward endcap EMC eZuce SRN meeting, 7th of November 2016, 14:00-15:15


  • Basel: -
  • Bochum: Cathrina, Claudius, Fritz-Herbert, Matthias, Malte, Miriam, Tom
  • Bonn: Christoph
  • Groningen: -
  • Stockholm: -
  • Uppsala: Pawel
  • GSI: -

Forward Endcap Crystals:

  • The remaining three tons of forward endcap PWO was moved from GI to BO last week: All forward endcap crystals are now located in Bochum and ready for subunit production.

Support Frame:

  • The support frame, i.e. the unit suspending the forward endcap and its frame during build up at the preassembly location Juelich, is now in production at a steel manufacturing company in Herne
  • The company (Riedl) is in close contact with the Juelich engeneers (J. Colienne et al.)
  • Finishing of the steel frame is expected before end of the year
  • The frame will also suspend the forward endcap during transport from Juelich to Darmstadt, part of it will be used in the insertion procedure of the endcap into the PANDA magnet


  • "Primer glued" radiation hard glass pieces back from irradiation at Strahlenzentrum GI: There is no deterioration of the coupling w/ primer observable
  • In conjunction with the former results of effectively unaffected transparency of the primer involved glueing we conclude to have found a solution for our glueing problems
  • Two more primer involved glueings have been prepared and are currently running temperature cycles. Still we have no failed primer involved glueing.
  • In this context and with closer looks to the capsules we think to not need a basic redesign of these parts; There is enough play to allow for a kink between photo detector equipped crystal and insert of 1.5-2 degrees which is much more than may happen inside an alveole.
  • We still need to look to a parallel movement of the crystals relative to the inserts which is possible in the order of only 0.5 mm
  • In order to be able to mount LEDs for radiation damage recovery we need to find small enough blue flat head types in order to not need to machine the VPTT capsules, for the APDs we definitely have to (or design and produce new ones)

VPTT Screening:

  • There are still some VPTT 'gain (1000 V)' measurements necessary to be done in Bochum (not as much as originally anticipated)
  • The latest Bonn measurements w/ decreasing VPTT response are not fully understood but can be corrected by referencing to the also decreasing response of the reference VPTT. Therefore B field gain loss screening is completely done now.

PANDA Hall HV Cabling:

  • There was some discussion about the HV cabling in the PANDA hall, based on drawings from Jost Luening: One half of the forward endcap is supposed to be supplied from the patch panel rack side while the other half is supplied by cables that are routed over the detector top, going down on the opposite side.
  • Need to ask Jost how detailed this scenario is in terms of necessary cable length. We foresee 2 m spare length on each side (also on the HV power supply racks side outside the PANDA hall...)

ADC Boards:

  • Malte presented some plots of linearity, resolution and bandwidth measurements done with the ADC board currently in Bochum, modifed to different shaping time inputs w/ equal range
  • Some of the results have been presented by Pawel on an IEEE conference
  • We are in favour of the third highest tested shaping time (which is...?), but studies on realistic noise background (added to the signals) is needed, for APDs as well as for VPTTs which rather differ in noise terms (HV filtering on APDs!)
  • Still to be done are also pile-up studies
-- ThomasHeld - 11 Nov 2016
Topic revision: r1 - 2016-11-11, ThomasHeld
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