General Meeting Summary 4/15/21

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PARTICIPANTS: Aaron Brown, Alex Camsonne, Fernando Barbosa, Bogdan Wojsekhowski, Carlos Munoz-Camacho, Carlos Yero, Rolf Ent, Hamlet Mkrtchyan, Paulo Medeiros, Tristan Anderson, Vardan Tadevosyan, Tanja Horn, Hakob Voskanyan, Marie Boer, Steve Wood


  • Tests carried out with the divider to investigate origin of noise (divider itself or measurement conditions) for different dynode shortening scenarios (dynode 9 and dynode 10)
  • background: dynode 9 is safest for PMT anode current based on previous studies reported at 4/1 NPS meeting, but noise was a major issue.
  • found that source of the noise is the divider itself
  • Path forward: design a new divider with the changes observed so far and with a new, externally powered amplifier
  • Design new divider
  • Prototyping
  • Finalize production by June
  • Connection divider to socket and testing
  • Impact of magnetic field on low HV PMT - no difference to before since main impact is distance to first dynode and that does not change.
  • Action Items
  • Prepare a summary of studies and optimized divider design based on them at the next meeting including:
  • Anode current for optimized design
  • Zero dynode? - generally the goal is: to stabilize gain as function of intensity (depends on the maximum current); need to determine if this is needed or not


  • Working with Chris C. to develop a way forward on the few HV qualification issues that remain. No resolution yet.
  • LED driver boards are in Procurement. The initial quotes were a little high - a few more vendors will be contacted. Should still be able to get them fabricated and on-site by this Fall though -- so no schedule impact.


  • HV supply cables tests - no load tests
  • overall stable - good!
  • Module Voltage vs. current tests - all channels
  • Variation ~10mV


  • Detector cart ready for procurement
  • Layout for detector cabling ready

SOFTWARE (Carlos Y.)

  • Finished clustering algorithm (Cellular automata) - based on Hall A DVCS
  • Compared total number of clusters with different algorithms (new cellular automata vs. standard hcana)
  • main difference is in definition of neighboring cells
  • new method produces more clusters
  • dependence on granularity
  • Optimizations ongoing
  • Action items:
  • Tracking
  • calclulate centroid of the cluster
  • project to target - line to target since it is neutral
  • correct for vertex
  • NPS simulations input to algorithm - Carlos M. will check with Ho San