Conference Call, March 8, 2007

From GlueXWiki
Jump to: navigation, search

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

  1. Analysis Methodology and Procedure for Extraction of Timing Resolution
    1. 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.
    2. 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.
    3. Base timing offset on North 7, ie all BCAL relative to itself. No tagger timing needed then at this stage.
    4. Walk correction.
    5. 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?
    6. 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.
    7. Examine tih and its sigma; hit info extracted from individual PMTs (from tic). Difference has beam spot effects included.
    8. 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.
    9. Preliminary discussion on eventual tagger inclusion, beam spot size, etc. For the former, we should chat with Elton, David and Simon.
  2. Blake's ADC-TDC (walk effect) Analysis Plots


Minutes

Attendees: Alex, Matt (Indiana), George, Blake, Zisis (Regina)

  1. Resolution Analysis: the following were deemed to be the main objectives of this analysis.
    1. 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 \sigma _{E}={\frac {a}{{\sqrt {E}}}}\oplus b, 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.
    2. Timing resolution (difference): This is easier to implement, considering that calibration/offset factors are less important. Alex's preliminary analysis shows \sigma _{{td}}={\frac {c}{{\sqrt {E}}}}\oplus d 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.
    3. 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.
  2. Details:
    1. Collection and posting of discriminator manuals and related docs.
    2. Verification of TDC->ns calibration from David Lawrence.
    3. Sanity check of timing offsets.
    4. Application of walk-effect corrections.
    5. Compare spread of timing between XP2020 and Burle 8875 PMTs.
    6. Extraction of quantities below in 50 MeV tagger energy bins.
  3. Key Quantities: all three below to be extracted as a f(z,θ).
    1. Energy resolution
    2. Diffence/position timing resolution (based on the subtraction of North minus South), see eq. 6 is Zisis' document.
    3. Average/TOF timing resolution (based on summing North and South), see eq. 8 is Zisis' document.
  4. Short-term Objectives
    1. Prepare for discussion and presentations at Collaboration meeting, by advance circulation of slides/document on the energy and timing resolution analyses.
    2. Prepare for PID review.

Useful Links

  1. Beam Test Run Plan
  2. Run Table
  3. GlueX E-Log
  4. Online DAQ Database
  5. CAEN Discriminator and ADC Manuals used in Beam Tests
  6. Excerpt from Zisis' timing resolution draft document: Media:TimeRes.pdf
  7. Alex's analysis of Runs 2334 and 2363: Media:gxdoc_ard2.pdf
  8. Alex's estimation of expeceted π0 mass resolution from BCAL Beam Tests: Media:gxdoc_ard5.pdf
Retrieved from "https://halldweb.jlab.org/wiki/index.php?title=Conference_Call,_March_8,_2007&oldid=64605"