Gabriele Cosmo
48 lines
2.8 KiB
Plaintext
48 lines
2.8 KiB
Plaintext
Prepared by R.Kokoulin, May 22nd, 2000
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Brief summary of G4 muon activity, May 2nd - May 23rd, 2000
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S.Kelner, R.Kokoulin, M.Maire, A.Rybin, L.Urban
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1. G4 muon tests
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The test procedure of the verification of muon interaction simulation which allows to check
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both mean free path calculation and energy transfer sampling has been suggested and
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implemented.
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First test results revealed appreciable deviations of the distributions of the energy loss from
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theoretical dependencies (for bremsstrahlung, pair production, nuclear interaction). Several bugs
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have been found and eliminated; it has greatly improved the agreement.
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The program of further G4 muon tests has been prepared and agreed, including thin target
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tests (extending the set of materials, energies, and increasing statistics), and thick target
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simulation which will allow to verify the consistency of consideration of restricted continuous
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energy loss.
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2. Refinement of the processes already implemented
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Simple formulae and algorithm for sampling photon and muon angles in muon
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bremsstrahlung have been suggested and prepared for implementation in G4. It will be coded in
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the nearest days.
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Final states for other processes (pair production, photonuclear interaction) have been
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clarified, fixed and introduced into documentation.
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Logical scheme of a consistent inclusion of bremsstrahlung correction in high-energy knock-
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on electron production and ionisation energy loss is prepared.
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List of questions concerning the validity of multiple scattering model has been compiled.
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After answering these questions, the "calibration" simulation of MCS for high-energy muons can
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be performed.
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3. Documentation
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Sections concerning three basic muon interaction processes (bremsstrahlung, pair production,
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photonuclear interaction) for PRM (Phys. Ref. Manual) have been extended, updated and
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corrected.
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Suggestions for improvements for the section in PRM about muon ionisation, and also
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comments and corrections for "Electromagnetic Physics" gallery have been prepared.
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4. Extension of the muon interactions in G4
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List of muon processes for further inclusion in G4 has been discussed. The processes of
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interest are: muon pair production by photon, muon pair production by muon, diffractive
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bremsstrahlung (which leads to a difference in positive/negative muon energy loss). Refinement
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of multiple scattering and introduction of the screening correction to bremsstrahlung and pair
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production based on recent calculations of radiation logarithm in HF model are also important
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and can improve the accuracy of G4-based simulations. The level of theoretical knowledge of
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these processes is sufficient for their implementation into algorithms and codes.
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Theoretical clarification of LPM and Coulomb corrections for electron pair production by
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muons is needed; these are important both for accelerator and high-energy cosmic ray
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applications.
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