Revision as of 12:43, 24 November 2021

SctParSim

A parametric simulation is a tool to receive a detector response without detailed description of interaction of particles with matter. The simulation is the part of the Aurora project, which is a software suit for SCTF.

Implemented detector subsystems:

drift chamber
FARICH PID system
calorimeter
muon system

The parametric simulation yields the detector response in the SCT EDM format thus allowing to analyze its result in the same manner as the result of the full simulation. The tracker and the calorimeter smear particle parameters according to a Gaussian distribution, while the FARICH PID and the muon subsystem use for that purpose the results of a pre-conducted standalone full Geant4 simulations.

How-to use the parametric simulation is demonstrated here

Detector configuration

The detector parameters can be changed in the run script (see Configuration section). The detector parameters and their default values can be viewed here.

SctParSimAlg

Name to change parameter	Description	Default value
B	Detector magnetic field	1.5
mostProbMass	The mass of most probable particle	0.13957

TrackSystemTool

Name to change paramater	Description	Default value
trackRhoMin	Inner radius of barrel tracker, m	0.1
trackRhoMax	Outer radius of barrel tracker, m	0.8
trackZMin	Inner z coordinate of endcup tracker, m	0
trackZMax	Outer z coordinate of endcup tracker, m	1
trackMinPt	Minimum momentum, GeV	0.05
trackPtProb	Registration probabilities for different momentum, {GeV, prob}	{{0.1, 0.8}, {0.3, 0.9}, {1, 0.95), {10, 0.99}}
trackRadLen	Radiation length in the track system, m	187
trackResParPT	Parameterizaton parameters for xy projection	0.00212
trackResParPZ	Parameterization parameters for z projection	{0.001281, 0.00308}
trackLayerAx	The radius of layers anf the location radius of the anod layers, mm	{{6.306, 217.306}, {6.644, 227.1}, {7.165, 246.906}, {6.564, 341.938}, {6.794, 352.06}, {7.14, 371.992}, {7.388, 382.95}, {6.651, 467.57}, {6.823, 477.718}, {6.968, 488.097}, {7.12, 498.701}, {7.274, 509.535}, {6.768, 636.322}, {6.898, 646.501}, {7.007, 656.957}, {7.121, 667.581}, {6.791, 750.730}, {6.902, 761.027}, {6.995, 771.472}, {7.091, 782.061}}
trackLayerSt	The radius of layers and the location radius of the stereo layers, mm	{{6.473, 280.136}, {6.747, 290.136}, {7.182, 310.863}, {7.486, 321.938}, {6.603, 405.941}, {6.799, 416.04}, {7.104, 436.741}, {7.314, 447.606}, {6.741, 533.35}, {6.859, 543.615}, {7.026, 554.088, {7.161, 564.762}, {6.778, 584.801}, {6.919, 595.108}, {7.039, 605.606}, {7.163, 6169.289}, {6.746, 689.948}, {6.865, 700.185}, {7.041, 720.09}, {7.165, 730.775}}

FARICHSystemTool

Name to change paramater	Description	Default value
farichRhoMin	Inner radius of barrel FARICH system, m	0.82
farichRhoMax	Outer radius of barrel FARICH system, m	0.9
farichZMin	Inner z coordinate of endcup FARICH system, m	1.02
farichZMax	Outer z coordinate of encup FARICH system, m	1.273
farichHoleR	Hole radius of FARICH system	0.3
parSimFarichFileName	The path to the file with response histograms of FARICH	./pi_ms_f1_mppc2_px3_d200_mla4_graph2d.root

CaloSystemTool

Name to change paramater	Description	Default value
caloRhoMin	Inner radius of barrel calorimeter, m	1.09
caloRhoMax	Outer radius of barrel calorimeter, m	1.55
caloZMin	Inner z coordinate of endcup calorimeter, m	1.293
caloZMax	Outer z coordinate of endcup calorimeter, m	1.86
caloCosthmax	Maximum cosine	0.9
caloClSize	Calorimeter cluster size, m	0.045
caloClSizeEGamma	Calorimeter cluster size for gamma, m	0.15
caloEMinBarrel	Minimal energy, GeV	0.015
caloEMinEndcup	Minimal energy, GeV	0.015
caloResPar	Parameterization parameters	{1.34e-2, 0.066e-2, 0.0, 0.82e-2}

MuonSystemTool

Name to change paramater	Description	Default value
muonRhoMin	Inner radius of barrel muon system, m	1.87
muonRhoMax	Outer radius of barrel muon system, m	2.15
muonZMin	Inner z coordinate of endcup muon system, m	1.88
muonZMax	Outer z coordinate of endcup muon system, m	2.16
parSimMuonFileNameMu	The path to the file with response histograms of muon system (muon)	./g4beamline_mu_plus_100k_parse.root
parSimMuonFileNamePi	The path to the file with response histograms of muon system (pion)	./g4beamline_pi_plus_100k_parse.root

Parameterization

Drift chamber

The track resolution is described here.

The parametric simulation has two options in the tracker to the particle identification: an ionisation clusters counting (dNcl/dx) and dE/dx. The model of calculation the specific number of ionization clusters is taken from a TraPID option by F. Gracagnolo (The presentation on "Joint Workshop on Future tau-charm factory" in December 4--7, 2018). An energy losing is calculated using the resolution model from BaBar experiment. The The $\sigma \left( \frac{dE}{dx} \right)$ is parameterized as

$\sigma \left( \frac{dE}{dx} \right) = \alpha \left( \frac{dE}{dx} \right) ^\beta dx^\gamma$

where α, β, γ is tuned on BaBar data.

Momentum resolution as a function of momentum depending on polar angle for π+
The dependence of the dE/dx on the momentum in the tracker system
The dependence of the specific number of ionization clusters on the momentum in the tracker system

FARICH PID system

The FARICH PID system works using the results of the full GEANT4 simulation. The system output is the particle speed and number of photons.

The dependence of the particle β factor on the momentum in the FARICH PID system
The dependence of the number of photoelectron on the βγ factor in the FARICH PID system for different angles (black - 10°, red - 30°, green - 45°)

Calorimeter

The calorimeter resolution is $\sigma_E = e_0 \bigoplus \frac{e_1}{E} \bigoplus \frac{e_2}{\sqrt{E}} \bigoplus \frac{e_3}{E^{0.25}}$ , the coefficients (e0, e1 etc.) are taken from the D. Epifanov presentation on Super C-Tau factory workshop in May 27, 2018.

There are two cluster sizes to gammas / electrons and other particles.

Reconstruction

The cross-linking data obtained by the track system and the calorimeter is implemented. This is implemented taking into account the geometric intersection of the calorimeter clusters.

The algorithm for the cross-linking data obtained by the track system and the calorimeter:

union of geometrically intersecting calorimetric clusters
finding a match between calorimetric clusters and tracks
recalculating cluster characteristics (time, energy, cluster size, conversion point)

The reconstruction efficiency for different particle types

Muon system

The muon system works using the results of a reconducted stand-alone simulation on G4BeamLine. The system is a cylinder of eight absorber and sensitive polystyrene layers. The absorber is iron.

The probability distribution for muons and pions to reach a certain layer in the muon system

Output collection

The output ROOT-file contains:

allGenParticles - MC particles
- pdgId
- charge
- vertex - x, y, and z coordinates
- p4 - momentum (px, py, pz) and mass

Particles - the particle characteristics after the parametric simulation
- pdgId
- charge
- vertex - x, y, z coordinates
- p4 - measured momentum (px, py, pz) and the most probability particle mass
- dedx
- dedx_err
- dncldx - cluster counting
- dedxPid
- dncldxPid
- farichPid
- muPid

TrackState - the helix characteristics (the track)
- phi
- theta
- qOverP
- d0
- z0
- referencePoint - x, y and z coordinates

CaloClusters
- energy
- time
- position - x, y and z coordinates of the calorimeter entry point

MuonHits
- layer - the last layer that registered a particle

FARICHHits
- cellId
- energy
- time
- beta
- beta_err
- nphe0
- nphe

The more characteristics have intuitive names.

@@ Line 1: / Line 1: @@
 = SctParSim =
 A parametric simulation is a tool to receive a detector response without detailed description of interaction of particles with matter. The simulation is the part of the Aurora project, which is a software suit for SCTF.
 Implemented detector subsystems:
@@ Line 8: / Line 8: @@
 * muon system
-The parametric simulation yields the detector response in the SCT EDM format thus allowing to analyze its result in the same manner as the result of the full simulation.
+The parametric simulation yields the detector response in the SCT EDM format thus allowing to analyze its result in the same manner as the result of the full simulation. The tracker and the calorimeter smear particle parameters according
+to a Gaussian distribution, while the FARICH PID and the muon subsystem use for that purpose the results of a pre-conducted standalone full Geant4 simulations.
-How-to use the parametric simulation is demonstrated [https://ctd.inp.nsk.su/wiki/index.php/SCT_parametric_simulation here]
+'''How-to use the parametric simulation''' is demonstrated [https://ctd.inp.nsk.su/wiki/index.php/SCT_parametric_simulation here]
 == Detector configuration ==

SctParSim (Aurora)