Dec 3, 2009 Readout

Teleconference Time: 11:00 a.m. EST

• ESNET and EVO session
• Phone:
  • +1-800-377-8846 : US
  • +1-888-276-7715 : Canada
  • +1-302-709-8424 : International
  • then enter participant code: 77438230# (remember the "#"). Phone connection only upon request.

Items for followup from previous meeting

1. Order prototype light guides (Elton)

Documents to Review

1. Plan for SiPM Testing (Carl and Fernando)
   • BCAL Readout Tests Using The Hamamatsu 4x4 Array
   • BCAL Readout Tests Using the SensL 4x4 SiPM Array
   • Report on Hamamatsu MPPC arrays

Tentative Agenda

1. Announcements
2. Review of Action Items
3. Results of tests of SiPMs (Fernando and Carl)
4. USM report
5. Light Guide Geometry
6. Light Guide Simulations
7. Discussions on MOU with USM

Minutes

Attending: Fernando, Carl, Elton, Eugene, Chuck, John, Beni (JLab); Zisis, George (UofR); Will, Alam (USM).

1. Announcements
   • JLab met with representatives from Hamamatsu this morning and reviewed measurements as well as the sequence of next steps in the evaluation.
2. Review of Action Items
   • Communication with Plastic Craft has not been very good and the light guide order has not been placed.
3. Results of tests of SiPMs
   1. Electronic certification (Fernando)
      • Fernando has completed the electronic certification of both Hamamatsu and SensL. Hamamatsu devices have met all our specifications. SensL package quality is very good and accompanied by quality documentation. However, the pulse lengths are about 200 ns long, exceeding our requirements.
      • Fernando has posted GlueX-docs summarizing the tests.
   2. Detector performance (Carl, see presentation posted)
      • Hamamatsu devices have been characterized for uniformity, dark current and PDE, achieving expected results in all areas.
      • Measurement of the amplitude vs changes in operating voltage show that there is a 10% amplitude variation for 56 mV change in Vop (or 1deg C).
      • Fernando: going forward, we will need to concentrate on mechanical and cooling considerations. This includes temperature stabilization in combination with bias compensation to thermistor changes.
      • Will: Have timing tests been performed with the sensors? No, but Fernando has measured the rise time (about 15 ns for both sensors). Scope pictures show that the response is quite uniform to LED pulsed illumination.
      • Elton: The next priority is to complete stress tests on the Hamamatsu units. This would give us the key information that we need to make the decision on technology. Completion of the performance measurements of SensL devices can wait till Jan.
4. USM report
   • Grant funds have been received, and they are diligently using them to setup the lab.
   • Serguei has been investigating options for purchasing light guides for various sources. A German company is a possible vendor PTW-Freiburg, Physikalisch-Technische Werkstaetten, Dr. Pychlau GmbH, Loerracher Str. 7, D-79115 Freiburg, Germany.
   • Pedro is working on new locations for FM pmts, attempting to simplify geometry and avoid compound angles.
   • The import of geometry from the cad program into GEANT4 has bugs, which were reported to the GEANT4 development team. While they are waiting for this issue to get resolved, Alam is inputting the geometry by hand, but his is taking time.
   • Changes in focus might be sensible if SiPMs are chosen for the readout. For example, Winston cone fabrication at the university is possible.
   • The Baby Bcal has arrived in Chile, but not yet at USM!
5. Discussions on MOU with USM
   • No progress, but should be elevated in priority.