December 21, 2007 Calorimetry

Connection

• The meeting will be held at 10:00 EST (9:00 CST)
• Phone:
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Agenda

1. Previous minutes: December 14, 2007 Calorimetry
2. Calorimetry Document Preparation
   • Resources Alex's draft GX_calorimetry).
     • Intro: GlueX-doc-856 and Media:reminder2.pdf
     • BCAL bullets: Media:BCAL_Highlights.pdf, FCAL list: Media:CalorimetryOutlineDoc.pdf
     • DocDB: BCAL Calorimetry Response, BCAL Facts, Amplitude Analysis, SciFi Emission Spectra Analysis
3. FCAL Hardware/Software
   • Light guides: ongoing, update
   • Low energy threshold: cosmics/Cherenkov: ongoing, update
   • Hadronic backgrounds: ongoing, update
4. BCAL Hardware/Software
   • SiPM Arrays: defect/distortion tests
   • Outer Bcal Light Guides: Preliminary notes (ES)
     • Toy model
     • Histogram Output
5. Any other business
   • Tracker: ActionItemTracker

Minutes

Attendees: Alex, Matt, Beni, Mihajlo (Indiana), Elton, Tim (JLab), Elke (DESY), George, Zisis (Regina)

1. Previous minutes: December 14, 2007 Calorimetry
   • No comments.
2. Calorimetry Document Preparation
   • Resources:
   • Status Quo:
   • Timelines:
   • Reviewers:
3. FCAL Hardware/Software
   • Mihajlo has been generating gp->b_1pi0 and f_1pi0 (all neutral) final states for reconstruction studies. The learning curve on high multiplicity events is taking more time than anticipated. Hopes to have results to show soon.
   • Alex mentioned that a comparison of Mihajlo's reconstruction with his parametric simulation has been conducted and agrees well. The input of photon detection for the parametric MC was parameterized from Mihajlo's output. For a_0 and a_2 production the realistic acceptance is about 30-35% and agrees between the two analysis. This reconstruction has been updated since the collaboration meeting where a 40% reconstruction efficiency was reported.
   • The reconstructed masses of pi0 is about 10-11 MeV, eta is 35 MeV. The widths agree between full reconstruction and MC. For photons that hit the Fcal only, the pi0 width is about 7 MeV and photons that hit the Bcal only the width is about 11 MeV.
4. BCAL Hardware/Software
   • George reported on the SiPM work. Two new results will be posted to the portal shortly. Conclusions from the Phase I tests are
     • Quality of SiPMs fell below expectations, at least for these early units
     • Factor of 2 variation in gain which is not acceptable
     • The sensor tiles showed extreme sensitivity of electronics to external parameters, such as the power supply and noise. Large pedestal widths are due mainly to the electronics.
     • Tested tiled arrays provide a proof-in-principle of use of detection over a large area, but characteristics are below specifications.
     • Carl asked for the voltage used for the reported tests: The breakdown voltate was 27.3 V, operation was about 28.8 V or about 1.5 V above breakdown.
     • SensL initially did not believe the large gain variations measured, but UofR measurements are reproducible and seem to stand up.
     • SensL has asked UofR to make further tests, specifically to check the connectivity from cell-to-cell, with they will do.