1 | Prepared by R.Kokoulin, May 22nd, 2000 |
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2 | |
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3 | Brief summary of G4 muon activity, May 2nd - May 23rd, 2000 |
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4 | S.Kelner, R.Kokoulin, M.Maire, A.Rybin, L.Urban |
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5 | |
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6 | 1. G4 muon tests |
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7 | The test procedure of the verification of muon interaction simulation which allows to check |
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8 | both mean free path calculation and energy transfer sampling has been suggested and |
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9 | implemented. |
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10 | First test results revealed appreciable deviations of the distributions of the energy loss from |
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11 | theoretical dependencies (for bremsstrahlung, pair production, nuclear interaction). Several bugs |
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12 | have been found and eliminated; it has greatly improved the agreement. |
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13 | The program of further G4 muon tests has been prepared and agreed, including thin target |
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14 | tests (extending the set of materials, energies, and increasing statistics), and thick target |
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15 | simulation which will allow to verify the consistency of consideration of restricted continuous |
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16 | energy loss. |
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17 | |
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18 | 2. Refinement of the processes already implemented |
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19 | Simple formulae and algorithm for sampling photon and muon angles in muon |
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20 | bremsstrahlung have been suggested and prepared for implementation in G4. It will be coded in |
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21 | the nearest days. |
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22 | Final states for other processes (pair production, photonuclear interaction) have been |
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23 | clarified, fixed and introduced into documentation. |
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24 | Logical scheme of a consistent inclusion of bremsstrahlung correction in high-energy knock- |
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25 | on electron production and ionisation energy loss is prepared. |
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26 | List of questions concerning the validity of multiple scattering model has been compiled. |
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27 | After answering these questions, the "calibration" simulation of MCS for high-energy muons can |
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28 | be performed. |
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29 | |
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30 | 3. Documentation |
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31 | Sections concerning three basic muon interaction processes (bremsstrahlung, pair production, |
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32 | photonuclear interaction) for PRM (Phys. Ref. Manual) have been extended, updated and |
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33 | corrected. |
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34 | Suggestions for improvements for the section in PRM about muon ionisation, and also |
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35 | comments and corrections for "Electromagnetic Physics" gallery have been prepared. |
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36 | |
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37 | 4. Extension of the muon interactions in G4 |
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38 | List of muon processes for further inclusion in G4 has been discussed. The processes of |
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39 | interest are: muon pair production by photon, muon pair production by muon, diffractive |
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40 | bremsstrahlung (which leads to a difference in positive/negative muon energy loss). Refinement |
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41 | of multiple scattering and introduction of the screening correction to bremsstrahlung and pair |
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42 | production based on recent calculations of radiation logarithm in HF model are also important |
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43 | and can improve the accuracy of G4-based simulations. The level of theoretical knowledge of |
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44 | these processes is sufficient for their implementation into algorithms and codes. |
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45 | Theoretical clarification of LPM and Coulomb corrections for electron pair production by |
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46 | muons is needed; these are important both for accelerator and high-energy cosmic ray |
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47 | applications. |
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