Gabriele Cosmo
69 lines
3.3 KiB
Plaintext
69 lines
3.3 KiB
Plaintext
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=========================================================
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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=========================================================
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Example ch2
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A. Sytov, G. Paternò
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INFN Ferrara Division, sytov@fe.infn.it, paterno@fe.infn.it
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INTRODUCTION
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Example ch2 is an enhanced version of ch1, providing the user with the full functionality of
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both the G4ChannelingFastSimModel and G4BaierKatkov, with parameters set up via a macro,
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in order to simulate the physics of channeling and channeling radiation/coherent bremsstrahlung.
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The example can be exploited for a wide range of cases to study coherent effects in
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a straight, bent or periodically bent crystal (crystalline undulator). Channeling
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physics in ch2 is active for protons, ions, muons, pions, electrons and their antiparticles.
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Any other charged particle can also be activated.
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DESCRIPTION
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The setup of the example ch2 is identical to ch1. As ch1, this example includes a bent crystal
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and a detector positioned behind it. Like ch1, it is based on the experiments on
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channeling [1] and channeling radiation [2] in a bent crystal, carried out at
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Mainz Mikrotron MAMI with 855 MeV electrons. The experimental validation of
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G4ChannelingFastSimModel is described in [3].
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However, since ch2 parameters are fully set up in the macro run.mac, this example
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is quite flexible and can be easily adapted for entirely different cases.
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A description of all the available options is provided in run.mac.
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It includes crystal and detector geometry, activation flags for
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G4ChannelingFastSimModel and G4BaierKatkov and various options.
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The example also provides detailed descriptions of various options for
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G4ChannelingFastSimModel and G4BaierKatkov, which can adjust model parameters
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depending on the specific case (see ConstructSDandField in DetectorConstruction).
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The front surface of the crystal is placed at z=0 (with z as the beam direction),
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while the front position of the detector can be set up via run.mac.
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The output is recorded into the file results.root as a set of root ntuples.
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These ntuples include:
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- crystal: particles recorded at the crystal entrance,
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- detector: all particles (except photons) recorded at the detector entrance,
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- detector_photons: photons recorded at the detector entrance.
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The format of every ntuple includes the following 10 variables (columns):
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"eventID", "volume", "x", "y", "angle_x", "angle_y", "Ekin", "particle", "particleID", "parentID"
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The variables represent:
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- the event number within the run (column 0),
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- the volume, either the crystal or the detector (column 1),
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- the coordinate (x,y) and the angles (x'=dx/dz, y'=dy/dz) of the impinging particles (columns 2-6),
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- the kinetic energy of the particle (column 7),
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- the particle name (column 8),
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- the particle ID (column 9),
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- the parent ID of the particle (column 10).
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To visualize these data, one should either open results.root using root TBrowser or use the python script analysis_ch2.py.
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REFERENCES
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[1] A. Mazzolari et al. Phys. Rev. Lett. 112, 135503 (2014).
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[2] L. Bandiera et al. Phys. Rev. Lett. 115, 025504 (2015).
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[3] A. Sytov et al. Journal of the Korean Physical Society 83, 132–139 (2023).
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