LAT Newsletter contributions from Beam Test Team
Issue 5 - submitted 25 july
Luca Latronico
July 25 2007
In the past two months the team performed much work behind the lines on the core software, to reorganize the BT sim/recon package (BTRelease), verify the consistency of the Geant4 simulation and better support the analysis. The main areas of activity have been:
- synchronization with GlastRelease and updates of core packages (hadronic physics list management, G4Generator), which will help transferring BT results to the main LAT simulation
- beam spot tuning from real data and transfer to the simulation
- comparison with mars15 simulation and interaction with developers, which revealed inadequacy of the mars15 code wrt G4 for describing a simple EM cascade
- comparison of different releases of the reconstruction package, which revealed some inconsistencies of the late reprocessing which should be fixed with new release
- study of the CAL response with different segmentations of the log, which did not show any dependance of the simulated CAL signal on the level of segmentation
The attempt to summarize the results and map the still existing discrepancies between data and MC, mostly in the TKR hit counts and the CAL energy deposit, continued and will be presented in the collaboration meeting talk:
- summary of the TKR hit and cluster MC simulation for hadronic events and comparison with data
- stability check of the CAL response in similar electron runs revealed dependancies of the relative CAL-TKR position and the effect of tkr converter gaps in the shower development; this confirms the importance of a good matching of the beam profile for comparison with the simulation
- cal response to pion runs ?
- angular resolution studies with high energy electrons and low energy tagged photons to complete the carachterization of the TKR performance over the whole spectrum
- PSF studies with covariance matrix
- started collecting existing and new ideas towards a set of selected runs and plots to produce for each new MC production
In order to start transferring our results to the LAT simulation as soon as possible and without delaying the production of the one year data simulation of the Service Challenge, we plan to provide now the existing improvements of the simulation to GR, and keep on evaluating the impact of the discrepancies through the production of custom files for the LAT with built-in discrepancies and potential new fixes we may find, to assess the impact of such discrepancies to background rejection and the LAT performances.
Issue 4 - submitted 31 may
Luca Latronico
May 31 2007
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