LAT September Newsletter - Beam Test contribution
Luca Latronico
September 12 2007
Since the final goal of the beam testa analysis is to validate and improve the LAT simulation-reconstruction package (GlastRelease, GR), we started tracking our progress and planning through a list of deliverables that have flown or will flow into GR.
The tables below reflect the state of the art of our work, including near term plans.
The first one is a list of the achievments that are now in place for the next Service Challenge run, while the second contains studies in progress and for the next months
Topic |
Software update |
Description |
Notes |
TKR Digi |
TkrDigi v2r6 |
includes charge sharing and ion signal |
two available routines, not enough to recover TKR hit deficit in MC |
ACD Digi |
GR-v11 |
better single photo-electron signal simulation by extending Poisson fluctuations to first dynodes amplification |
|
CAL Calibration Procedure |
column-wise charge injection in CAL CPT online scripts |
correct non-linearities in charge injection |
improved CAL calibration but did not solve energy shift; will be default calibration mode for the LAT, not relevant for simulation |
CalRecon |
GR-v11 |
correct logs and inter-range cross-talk |
require mapping of cross-talk for the LAT |
Hadronic physics list |
GR-v12 |
|
improved model for hadronic interactions (Bertini model up tp 10GeV, QGSP model up to 20GeV) |
TKR material audit |
GR-v12 |
real TKR thin converter thickness |
8% lower wrt to original design |
List of planned deliverables and expected delivery
Topic |
Expected delivery |
Description |
Notes |
TKR material audit |
end september |
update mass of passive material to real values from measurements |
known missing mass in current model mostly around active area |
CAL material audit |
end september |
check and update CAL mass and materials |
preliminary surveys indicate good model |
TKR alignment in MC |
quick fix available in GR-v12 |
fix bug in MC alignment |
checking out alternative alignment strategy |
New mass simulation |
end september |
with latest sim-recon package |
will be used to re-evaluate TKR hits deficit and CAL energy shift in simulation |
Special TKR geometry simulation |
in progress |
vacuum layer between silicon layers and tray core |
performed to check penetration of delta rays in a more realistic geometry; preliminary results indicate little effect on TKR hits |
Low-energy simulations |
in progress |
systematic test of LE EM physics list in G4 and range cutoff studies |
preliminary results indicate no effect of range cutoffs and a non-perfect control of LE physics list in our simulation |
background simulations with higher TKR hits |
end september |
increase artificially number of TKR hits to mimick BT data |
will use alignment bug and will check effect on background rejection |
background simulation with shifted CAL energies |
end september |
artificially scale simulated CAL energies and most important CAL variables to mimick BT data |
will check effect on background rejection and reconstruction algorithms |
final best physics list |
november |
final MC tuning |
should flow into the Service Challenge 1 year run. it will includes best physics list and modification to geometry |
A very useful tool that we recently developed to check rapidly the effect of the many changes we are recently testing in the simulation is a BtSystemTest toolkit, which is a collection of the most sensitive plots produced so far by our team that are automatically produced for each MC generation, so that we can quickly evaluate the effect of changes.
Recently some effort went into use of BT data to check the expected behaviour of trigger primitives from the calorimeter with large energy deposit, which are not avaible with standard cosmic ray data from the LAT.