Conference Call, March 8, 2007
From GlueXWiki
Hi Matt and Alex:
this is a reminder for our Indiana-Regina teleconference regarding the BCAL beam test analysis on Thursday March 8 at 11:30 EST.
Connection
Call IU at (812) 856-5808
Agenda
- Analysis Methodology and Procedure for Extraction of Timing Resolution
- Attachments (see below): Alex's note (Alex, was there a later version of this?), and a few pages from a draft note I've been working on, to define calculated quantities. Equation nos below refer to my draft note.
- Extraction of sigma_tres will be done in 50 MeV bins to get the energy dependence. Blake is set up for this, but in the future we can changed it if need be.
- Base timing offset on North 7, ie all BCAL relative to itself. No tagger timing needed then at this stage.
- Walk correction.
- Rough/quality checks: Plot tic (eq 4) (assuming no-walk, ie that individual PMT TDCs have been corrected for walk), and extract its sigma. Compare North vs South PMTs from cell 7 with XP2020 PMTs (a "juicy" cell with lots of energy). Then compare with a pair in the rear that has Burle 8875 PMTs. At this stage do we see the better XP2020 performance?
- Mean Timer: Extract tarr (eq 7) and its sigma. This is a first/fast/coarse extraction of tres. Beam spot size not a significant contributor here.
- Examine tih and its sigma; hit info extracted from individual PMTs (from tic). Difference has beam spot effects included.
- Calculate weighted average tav (eq. 8) and sigma. This is the IU methodology as outlined in your TOF NIM A494 (2002) 495, also as GlueX-doc-239. It looks reasonable to extend this sum from n=1,36 for all readouts in the beam test. Beam spot also plays a role here.
- Preliminary discussion on eventual tagger inclusion, beam spot size, etc. For the former, we should chat with Elton, David and Simon.
- Blake's ADC-TDC (walk effect) Analysis Plots
Minutes
Attendees: Alex, Matt (Indiana), George, Blake, Zisis (Regina)
- Resolution Analysis: the following were deemed to be the main objectives of this analysis.
- Energy resolution: this has been extracted by Alex, Blake and Christine for Run 2334 (normal incidence in the middle of the BCAL, ie at z=0cm). All agree and the number is , with a being around 5% and b around 1%, consistent among the three analyses, and independent of incident angle. Christine's analysis from the 'absorber' runs shows degradation of the floor term b, consistent with expectations.
- Timing resolution (difference): This is easier to implement, considering that calibration/offset factors are less important. Alex's preliminary analysis shows with c=106 and d=150. Design goal is c=50 and d=150 (KLOE has 54 and 136, respectively). The c=106 is undoubtedly so large because of the uncorrected data due to walk. Blake has started work on this and this resolution will be pursed first.
- Timing resolution (average): The beam spot size does play a role here (the beam spread needs to be separated from the intrinsic resolution in the calorimeter/electronics), and the offsets need to be known very well. This resolution will be extracted second.
- Details:
- Collection and posting of discriminator manuals and related docs.
- Verification of TDC->ns calibration from David Lawrence.
- Sanity check of timing offsets.
- Application of walk-effect corrections.
- Compare spread of timing between XP2020 and Burle 8875 PMTs.
- Extraction of quantities below in 50 MeV tagger energy bins.
- Key Quantities: all three below to be extracted as a f(z,θ).
- Energy resolution
- Diffence/position timing resolution (based on the subtraction of North minus South), see eq. 6 is Zisis' document.
- Average/TOF timing resolution (based on summing North and South), see eq. 8 is Zisis' document.
- Short-term Objectives
- Prepare for discussion and presentations at Collaboration meeting, by advance circulation of slides/document on the energy and timing resolution analyses.
- Prepare for PID review.
Useful Links
- Beam Test Run Plan
- Run Table
- GlueX E-Log
- Online DAQ Database
- CAEN Discriminator and ADC Manuals used in Beam Tests
- Excerpt from Zisis' timing resolution draft document: Media:TimeRes.pdf
- Alex's analysis of Runs 2334 and 2363: Media:gxdoc_ard2.pdf
- Alex's estimation of expeceted π0 mass resolution from BCAL Beam Tests: Media:gxdoc_ard5.pdf