December 14, 2007 Calorimetry
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Connection
- The meeting will be held at 11:00 EST (10:00 CST)
- ESNET No.: 8242553 (If ESNET is not an option for you, please let Zisis know in advance, so that we can patch in the telephone line below)
- Phone:
- +1-800-377-8846 : US
- +1-888-276-7715 : Canada
- +1-302-709-8424 : International
- then enter participant code: 39527048# (remember the "#")
Agenda
- Previous minutes: November 29, 2007 Calorimetry
- Calorimetry Document Preparation
- Resources (see Alex's link).
- Intro: Media:GX_calorimetry.pdf, 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
- Tracker: ActionItemTracker
- Resources (see Alex's link).
- FCAL Hardware/Software
- Flash ADC Timing: see Email List Server
- Light guides: ongoing, update
- Low energy threshold: cosmics/Cherenkov: ongoing, update
- Hadronic backgrounds: ongoing, update
- BCAL Hardware/Software
- SiPMs: ongoing, update: Testing report of SiPM-arrays under Phase I
- SiPMs @ JLAB: trenched 1mm^2 sample: Media:Trenched_A20H_Results.pdf
- Light Output: SciFi Emission Spectra Analysis and discussion of number of photoelectrons (Alex will provide a document for this)
- CFDs: goals and procedures for discriminator testing
- Monte Carlo: report from Richard
- FCAL-BCAL Hole: preliminary photon conversion plots with new geometry (Richard)
- Any other business
Minutes
Attendees: (IU) Alex, Mihajlo (UofR) George, Andrei (Athens) Christine (JLab) Elton, Tim, Carl.
Zisis was not online. Elton took minutes.
- Previous minutes: November 29, 2007 Calorimetry
- No comments.
- Calorimetry Document Preparation
- 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.
- 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.
- New detectors (advertized on the SensL web-site) are expected both at UofR and Jlab and will be re-tested. The Jlab detector group is also ordered an array that allows readout of each of the cells separately.
- Fibers: Carl has received batch of fibers from St. Gobain (half to be shipped to UofR) early next week. Fibers from Kurary were ordered a week ago.
- George reported on the SiPM work. Two new results will be posted to the portal shortly. Conclusions from the Phase I tests are
- FCAL-BCAL Hole: preliminary photon conversion plots with new geometry (Richard)
- Richard was not available at the phone conference.