Oct 7, 2009 Readout

Teleconference Time: 12:15 p.m. EST

• ESNET and EVO session
• Phone:
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Items for followup from previous meeting

1. Ship Baby Bcal to USM.
2. Make progress on USM MOU document (Elton, Will, Eugene)
3. Optimization of Bfield direction and magnitude relative to pmt
4. Light collection efficiencies for light guides for "USM" geometry.

Documents to Review

1. Media:Draw trigs 38deg.pdf Media:Draw trigs 73deg.pdf for segment #2.
   • Entrance rectangle is 3.01x4.0 cm. Exit radius is 1.35 cm. Length of trapezoid/cone is 60 cm, and length of torus is also 60 cm.
   • This configuration should be comparable to Alam's "cylindrical cone" geometry.
2. See also Effective diameter vs B field and angle from Antonelli et al., NIMA 368 (1996) 628-634.
3. Magnetic field plots
   • Media:Plot bfield tot downstream.png
   • Media:Plot bfield theta downstream.png
   • Media:Plot bfield tot upstream.png
   • Media:Plot bfield theta upstream.png

Tentative Agenda

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

Minutes

1. Attending: Elton, John, Fernando, Carl, Tim, Sasha, Beni (Jlab); Eduardo, Sergey, Will, Alam (USM); Zisis, George, Andrei (Regina).
2. Announcements
3. Review of Action Items
   • Progress on all issues except for shipping of baby cal to USM. Alam is in conversation with university administration and hopes to resolve the issue in a couple of weeks.
4. Plan for SiPM Testing (Carl and Fernando)
   • Five SiPM units from Hamamatsu arrived this morning. Will be picked up by Carl. Expect remaining five units to be shipped next week.
   • Fernando: Electronic assemblies are almost complete. Will begin testing electronics for Hamamatsu units on Monday.
   • Carl confirmed the tentative test plan for the SiPMs. Will begin by checking individual cells in the array. Then run a linearity curve, leaving some units exposed to high light levels for a period, before checking their quiescent state.
5. USM report
6. Light Guide Geometry
   • Pedro is changing the geometrical model to set the FM pmts to an angle of 15 deg to the field. Should be finished by Fri or Mon.
   • Will post .iges files from SOLID MODEL where we can download them an enter them into our 3D mechanical model.
   • Pedro: Noted that measurements by Hall D group are incomplete and should be filled before final decisions are taken. Elton noted that the NIM article from KLOE has additional information that might fill in these gaps.
   • The plots of the Bfield which were posted can be checked against the ROOT file which USM is using as a basis for setting the angle of the FM pmts.
7. Light Guide Simulations
   • George emphasized that prototypes must be built and measured to check the absolute normalization of transmission.
   • From last wg meeting: Elton had confirmed the high geometric efficiency (>98%) of these light guides. Inclusion of the attenuation length reduces the efficiency to about 57%.
   • The changes to the geometry are not expected to change the geometrical efficiency very much, but this needs to be confirmed.
8. Discussions on MOU with USM