Oct 15, 2009 Calorimetry

Teleconference Time: 11:00 a.m. EST

• ESNET and EVO session
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Items for followup from previous meeting(s)

1. Fcal
   • Need to discuss strategy for fabrication of boards. Paul is concerned primarily about the HV board. We should include Fernando and Chris on the discussion for suggestion of production.
   • CR to modify schedules for new activities, including Fcal calibration. Elton to send proposal to listserver for comments.
2. Bcal
   • Web page needs to be setup for communications.
   • Decide on a strategy for how to use fibers with slightly different systematics into matrix construction (e.g. randomizing them in the matrix). (everyone)
3. Bcal readout
   • Review decision on the orientation of FM pmt relative to Bfield, including tolerances due to expected field changes. (Elton, Will, Alam, Pedro)
   • Alam will see if Pedro can generate new orientations of the pmts at an angle of 15 deg relative to the B field.
   • Should order prototype light guides for typical configurations

Tentative Agenda

1. Announcements
2. Review of Action Items
3. Calibration/Monitoring
4. Fcal
5. Bcal
   • Status of construction / Readiness Review Schedule
   • Fibre QA: Shipments 1-5 (GlueX-doc-1366)
6. BCAL Readout
   • SiPM testing (Carl and Fernando)
   • New geometry for light guides (Alam/Pedro)
   • Light guide prototypes. See Quote from Plastic Craft and Ray tracing through light guides
7. Other business

Minutes

Attendees: Elton, Beni, John, Tim, Sasha, Eugene (Jlab); Zisis, George, Andrei (UofR); Pedro, Alam (USM); Christine (Athens); Matt, Ryan, Claire (IU).

1. Announcements
2. Review of Action Items
   • Progress on essentially all items.
3. Calibration/Monitoring
   • Beginning to setup test of monitoring system with plexiglass. Input light and measure output with pmt viewing side of plexiglass.
   • Matt suggested to use an airgap between pmt and plexiglass to make the setup more realistic.
4. Fcal
   • Working on budget response to the JLab RFP. Should have preliminary numbers by next week. Suggests a phone conference with JLab to get feedback.
5. Bcal
   1. Status of construction / Readiness Review Schedule
      • Machining of construction prototype is in progress, and on schedule, at Ross machining. Zisis will send a status/update tomorrow afternoon and tickets to the Review will be purchased based on the outcome.
      • Ross has requested 2 weeks to machine the construction prototype, which includes all the features in the end-plate. The time per module will be reduced to one week in production.
      • Dan is officially on board as the construction manager!
      • Tomorrow they will draft the mid-month report. These will be posted on a web site which is under construction.
   2. Fibre QA: Shipments 1-5 (GlueX-doc-1366)
      • Report on first-article fibers has been sent to Kuraray.
      • Kuraray has implemented all suggestions and feedback we have given them.
      • Can now test 30-40 fibers at each station.
      • 0.5-1.0% of all fibers are being tested (same quantity as Kuraray)
      • Zisis showed summary slides of progress and testing of fibers. There are some variation between shipments, but they meet specification. The new procedure will use rough cut/blackened ends. For comparing shipments the earlier measurements should be adjusted from the polished/black end procedure.
      • Shipment #4 seems to have a mixture of fiber responses, which could be due to small variations in the 2nd dopant which is mixed in at the % level. Still the variations are small relative to the overall quality of the fibers.
      • Report on shipments 1-5 will be available by month's end for feedback to Kuraray and completion of the customer satisfaction survey.
   3. We still need a discussion/decision on how best to distribute fibers within the calorimeter.
      • The consensus is that a uniform mixture is best, but not clear how to achieve this in an efficient manner.
      • Zisis/George will contact KLOE to find out if they had any special strategy.
      • Andrei will try to estimate variations in MC due to systematic variations in fiber attenuation length and light output.
6. BCAL Readout
   1. SiPM testing (Carl and Fernando)
      • Five units have been delivered from Hamamatsu, and five more expected next week.
      • Fernando is mounting them on his electronics and will complete initial electrical tests early next week. Carl will test the sensors themselves when Fernando qualifies the electronics.
   2. New geometry for light guides (Alam/Pedro)
      • Pedro has provided files of the 3D model from Solid Works and Jlab has successfully read them into their system. Thanks!
      • The current geometry took the original configuration and rotated it by 15deg. There is still optimization that can be done in the model as some of the light guides are now bent by 90 deg. However, it is a good starting point.
      • The geometry for the first section of the light guide was obtained by using a linear transition from the rectangular cross section down to a circle. This is somewhat different cutting a rectangle down using a cone shape (which is used for the geometries that model light guides).
      • Elton: This is ok for now. The model shows that this geometry can work. We next need to find out from manufacturers what they can machine and check the optics of those shapes.
   3. Light guide prototypes. See Quote from Plastic Craft and Ray tracing through light guides
      • Elton has run efficiency calculations for the outer segment #13. When using a 1.5" pmt (radius=1.35cm photocathode), there is considerable geometrical losses. If a 2" pmt is used (radius=1.95 cm photocathode), the geometrical inefficiencies essentially disappear. The geometry for use of the 2" pmt needs to be checked. Tim noted that there is more space after the light guides are bent. We should investigate this further because there could be considerable gains in collection.
      • JLab will investigate purchasing some prototypes from Plastic Craft. USM will investigate options for producing prototypes in Chile.
7. Other business