ToT-analysis

Analysis of the ALICE 3 tracker PID using ToT

Requires O2 from https://github.com/hfribert/AliceO2, branch ToT-pixcharge (stores the charge of every cluster pixel). Run everything from the O2 environment.

Simulation

export ALICE3_SIM_FIELD=ON
export ALICE3_MAGFIELD_MACRO=<O2 source>/Detectors/Upgrades/ALICE3/macros/ALICE3Field.C

# TF3 = TOF (only as material here); add A3IP to -m to include the beam pipe
o2-sim-serial-run5 -n 50 -g boxgen -m TRK FT3 TF3 --seed 1 \
  --configKeyValues "Diamond.width[0]=0.01;Diamond.width[1]=0.01;Diamond.width[2]=5;BoxGun.pdg=211;BoxGun.number=20;BoxGun.eta[0]=-3;BoxGun.eta[1]=3;BoxGun.prange[0]=0.1;BoxGun.prange[1]=5;BoxGun.phirange[0]=0;BoxGun.phirange[1]=360;IOTOFBase.segmentedInnerTOF=true;IOTOFBase.segmentedOuterTOF=true;IOTOFBase.enableForwardTOF=false;IOTOFBase.enableBackwardTOF=false"

Digitization

o2-steer-colcontexttool -i o2sim,200000,50:50 --use-existing-kine \
  --with-vertices kNoVertex --orbits 3 --orbitsPerTF 32

# ALMIRA response file; without --local-response-file the APTS response from CCDB is used
o2-sim-digitizer-workflow -b --run --onlyDet TRK,FT3 \
  --interactionRate 200000 \
  --incontext collisioncontext.root \
  --local-response-file <path>/ALICE3OTResponseData_v2.root \
  --configKeyValues "TRKDigitizerParam.noisePerPixel=1e-7;TRKDigitizerParam.chargeThreshold=91;FT3DigitizerParam.noisePerPixel=1e-7;FT3DigitizerParam.chargeThreshold=91;HBFUtils.nHBFPerTF=3"

Clusterization

o2-alice3-trk-reco-workflow -b

Cluster export

ExportClusters.C writes the TRK and FT3 clusters into a flat ROOT file, with the seed pixel charge and the MC truth.

root -l -b -q '<repo>/ExportClusters.C+("<simulation directory>", "clusters.root")'

Tree clusters (one entry per cluster):

Branch	Meaning
det	0 = TRK, 1 = FT3
layer	TRK 0-10 (VD 0-2, ML/OT 3-10), FT3 disk 0-11
chipID	O2 sensor index
row, col	seed pixel on the sensor
qSeed	seed pixel charge [e-]
x, y, z	global cluster position [cm]
event, trackID	MC particle (-1 for noise)
pdg	PDG code

Tree particles: event, trackID, pdg, primary, mother, vertex vx, vy, vz [cm], momentum px, py, pz [GeV/c].