Simulations
for Combined Beam Test EMEC/HEC/FCAL in 2004

	Simulations and digitization enviroment
	Output data format
	Simulated data

Simulations

For combined beam test of EMEC/HEC/FCAL modules, which took place at CERN in 2004, simulation code for the GEANT4 is available. There is older standalone version, based on the package used for the simulation of EMEC/HEC combined beam test in 2002, which is now deprecated.

For the NIM publication, the simulation was done with athena rel. 11.0.5, desription of those simulation could be found here.

Currently the simu+digi+reco is done either using rel. 14.0.0 with following list of additional packages, or rel. 14.2.0 with much shorter list. There are still two packages with changed files, which doesn't have a tag in CVS (CaloDetDescr and G4AtlasApps), please take a changed files from:
/afs/cern.ch/user/p/pavol/scratch0/athena_tbsimul_geo_1400/Calorimeter/CaloDetDescr

The geometry classes are in LArGeoH62004Algs package, where also steering jO could be found. Some hits manipulation and Sensitive Detectors calculators are in LArG4H6SD package.

• EMEC inner wheel module0
• eight HEC short (inner part) modules
• two FCAL modules
• Cold Tail Catcher
• BPCs and MWPCs
• scintillator counters

Output of simulations is saved in POOL hits file, with possibility to switch on also output to ROOT TTree in the format of stand-alone package.

The following properties are fixed in the code:

• "pencil-like" beam, or smearing according a parameters from jO
• beam angle is computed according user parameter: Y-table position

The following properties and parameter settings is possible to change via the jobOptions ( jobOptions.G4TB_LArH6-2004.py available in the share area of steering package):

• X position of the cryostat, and Y position of table (and consequently beam)
• particle type and energy
• charge collection in EMEC: switch on or off
• running period (run1 true or false)
• CalibrationRun switch on or off
• possibility to switch on also old-type output ROOT file
• number of events to simulate (line theApp.EvtMax)
• the name of G4 macro to run (line G4Svc.FADSMacro)
• the name of the output file (line Stream1.OutputFile)
• verbosity of output (line MessageSvc.OutputLevel)
• random number generator initial seed (line AtRndmGenSvc.Seeds)

Relative longitudinal position of calorimeter modules (EMEC, HEC, FCAL) is kept as it is foreseen in the ATLAS detector. Position of the set of modules inside cryostat is characterized by the following.

• X: EMEC shift 10 mm with respect to X cryostat=0
• X: HEC shift 2.5 mm with respect to X cryostat=0
• Y: beam at Y=0 (in run1) enters modules at the point 435. mm above the module axis (= beam line in ATLAS) - to be checked if it's correct
• Z: front face of the EMEC envelope is

Digitization

The Digitization steering jO jobOptions.DigTB_LArH6-2004.pyis in the geometry package as well. The basic difference from the standard LArDigitization is using of different Identifier dictionaries, and special CondDB folder (LArElecCalibDC2) for shape and noise parameters.
The recomended way is run digitization without noise addition, and then mix a real noise events (from random triggers) at the first stage of reconstruction, the TBCellNoiseCorrection algo in TBRec package. More details in reco section.

Output data format

• Standard output from simulation job is the POOL hits file. The standard LArHitContainer, EventInfo and TBEventInfo objects are stored there. In addition the are TB specific informations stored in AthenaHitsVector of LArG4H6FrontHit, LArG4H6WarmTCHit (all in LArG4TBSimEvent package.
• In the Calibration run, the standard CaloCalibrationHitContainer is stored.
• If one switch on the old-type output, also the ROOT file with LArG4TBEndcapRun class storing run info and LArG4TBEndcapEvent class storing events info, is produced. The more detailed description of variables stored in the TTree is also available.
• The energy deposits within one event are summed for each readout channel, and the stored "address" for energy depositions in LAr and absorber is the readout channel, according standard TB mapping), using the flat readout channel numbering

Available simulated data

• The naming convention for all data on Castor (tarballs as well as individual files) is:
  ftype_energy_ptype_x_y_fnum.ext
  where:
  • ftype - file type (g4hits for geant hits and so on)
  • energy - beam energy in GeV (could have decimal points
  • ptype - PDG code of beam particle
  • x and y - nominal X and Y coordinate of beam
  • optional fnum - file serial number, if there is more files with the same name
  • ext> - file extension (.tar or .pool.root )
• The data so far simulated are available on Castor in /castor/cern.ch/atlas/project/larg/cbt-ec2/MC/14.0.0
  Some of the data (pion x and y scan) has small bug in Calibration hits (some has wrong address), but regular hits are O.K. in all files putted on castor.

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