Minutes for 24-Jan-2006 Meeting at RHUL

We had short reports on:

1. News from Calice Orsay meeting
   Since Orsay, DESY test beam for ECAL proposed to start mid-Apr.. Shifts would require 2 people if flammable gas, Japanese colleagues will now allow variation of the gas mixture in their drift chambers such that no longer flammable (but lower efficiency). Would need to be used premixed. Several people (incl. PD) would be at DESY mid-Feb and could test tracking efficiency. Sign up list for shifts would be made available for the next DESY run. Currently still 16 layers of ECAL, expecting 50 more wafers (~9 layers) from Korea, but not know what usable yield will be.

2. Updates
   • Physics Studies, Michele
     Used D10scint model, found missing energy in Z to mu pair channel of ZHH events (not seen in corresponding Z to electron pair channel). Various suggestions to understand such as looking at simpler Z production events. Suggested to use LDC01 detector model also. Fabrizio had contacted Norman Graf about (in)compatability problem with some of the sdthep files available c/o SLAC.
   • Experience with Geant4.8.0, David
     Reported on result of recent improvements to e.m. modelling in G4.8.0 and addition of upstream material in mokka test beam model. Improved consistency with data in basic energy/position/sum energy distributions. For pion beam, variation between models/versions leads to changes ~15% in energy deposited (total and in Ecal/Hcal, and no. of clusters).
   • Grid certificates, Nigel
     Brief summary of process necessary to become member of CALICE VO

3. Minimum aims (for LCWS)
   • Test beam data analysis
   • WW/ZZ separation plot - 0.3/sqrt(E)?
   • Detector optimisation: variation of length, B field, radius, granularity (longitudinal and transverse)
   • Presentation of MAPS (concept, backed up by some performance indicators, h/w and s/w aspects)?? - less likely, given attendees from UK

   Followed by:

4. Round table discussion
   • Physics Studies
     • Single particle energy resolution, Mike G. had studied this using D10Scint model, did not find expected 13%/sqrt(E).
     • Event display, useful for debugging code/algorithms. CEDViewer as a Marlin package and Wired4 as plugin to JAS3 available. Geometry of detector will be displayed using Gear (XML) file (CEDViewer) or Heprep (Wired4, usually produced by Geant4), respectively. Some problems with using Wired with full detector heprep from Geant4 (too much information/file size).
     • Mark's alternative/extension to Alexei R's Wolf clustering - use default Wolf clustering for present
     • Gear files - for LDC, see example distributed with MarlinReco as starting point: .../packages/MarlinReco/examples/LDC/gear_ldc.xml
   • Test beam preparation
   • Long discussion about studies required, and for related data analysis, leading to "Task List", below.

5. Next steps
   • Mike - single e-/mu- resolutions, look into weighting by thickness of absorber layers
   • Michele/Fab. - physics study, understand missing energy in muon channel, try using LDC01 detector model?, try using particle id to separate mu/e from hadronic jets before forcing rest of event to 4 jets.
   • George - setting up for test beam from his experience last year
   • David - simulations of samples using latest mokka/G4 for test beam configuration, made available on web
   • Nigel - MAPS into LDC01 model?
   • Fab. - look into change of tracker hits to calorimaterHits for the scintillator model, investigate application of threshold to drift chamber hits

Task list (24-Jan-version)

Analysis

1. Energy resolution vs. energy, angle
2. Position resolution vs. energy, angle
3. Angular resolution vs. energy, angle
4. Comparision and tuning of simulation to data
5. Comparision of calibrations in cosmics vs. real data
6. Efficiency, dead space between pads and wafers

Electronics/DAQ understanding

1. Coherent noise
2. Crosstalk
3. Shaping times
4. HOLD timing setting

Reconstruction

1. Tracking calibration, alignment, material mapping and track fitting
2. Pedestals vs. time, noise vs. time
3. Pedestals vs. ttemperature, noise vs. temperature
4. Cosmics data, new vs. old gain
5. Comparison of electronics calibration, cosmics calibration, electron beam calibration
6. Systematic production of reconstructed data files for all runs

Run planning

1. Optimisation of missing slab positions; where to place inactive slabs if not received sufficient wafers
2. Need for electronics calibration; how often?
3. Need for/from electron beam calibration; scan of each pad?
4. Recording physical configuration (photos/survey of drift chambers, scintillators)

Run monitoring

1. Immediate online monitoring
2. Semi-online bin file monitoring
3. Semi-online LCIO monitoring
4. Book keeping during shifts
5. Recording test beam conditions (from accelerator)

Simulation

1. Digitisation of tracking hits, remove low energy sim hits
2. Storing truth particle positions at tracking chambers and ECAL front face
3. Digitisation of ECAL; add noise (channel-by-channel), threshold, time-dependence due to preamp shaper, crosstalk, coherent noise
4. Systematic production of standard MC samples of 100k events
5. Systematic production of digitised and reconstructed simulation samples from the above