[831] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // |
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[850] | 27 | // $Id: G4EqMagElectricField.cc,v 1.14 2008/04/24 12:33:35 tnikitin Exp $ |
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[921] | 28 | // GEANT4 tag $Name: geant4-09-02-cand-01 $ |
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[831] | 29 | // |
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| 30 | // |
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| 31 | // This is the standard right-hand side for equation of motion. |
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| 32 | // |
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| 33 | // The only case another is required is when using a moving reference |
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| 34 | // frame ... or extending the class to include additional Forces, |
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| 35 | // eg an electric field |
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| 36 | // |
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| 37 | // 10.11.98 V.Grichine |
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| 38 | // |
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| 39 | // ------------------------------------------------------------------- |
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| 40 | |
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| 41 | #include "G4EqMagElectricField.hh" |
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| 42 | #include "globals.hh" |
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| 43 | |
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| 44 | void |
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| 45 | G4EqMagElectricField::SetChargeMomentumMass(G4double particleCharge, // e+ units |
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| 46 | G4double, |
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| 47 | G4double particleMass) |
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| 48 | { |
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| 49 | fElectroMagCof = eplus*particleCharge*c_light ; |
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| 50 | fMassCof = particleMass*particleMass ; |
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| 51 | } |
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| 52 | |
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| 53 | |
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| 54 | |
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| 55 | void |
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| 56 | G4EqMagElectricField::EvaluateRhsGivenB(const G4double y[], |
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| 57 | const G4double Field[], |
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| 58 | G4double dydx[] ) const |
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| 59 | { |
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| 60 | |
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| 61 | // Components of y: |
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| 62 | // 0-2 dr/ds, |
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| 63 | // 3-5 dp/ds - momentum derivatives |
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| 64 | |
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| 65 | G4double pSquared = y[3]*y[3] + y[4]*y[4] + y[5]*y[5] ; |
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| 66 | |
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| 67 | G4double Energy = std::sqrt( pSquared + fMassCof ); |
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| 68 | G4double cof2 = Energy/c_light ; |
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| 69 | |
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| 70 | G4double pModuleInverse = 1.0/std::sqrt(pSquared) ; |
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| 71 | |
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| 72 | // G4double inverse_velocity = Energy * c_light * pModuleInverse; |
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| 73 | G4double inverse_velocity = Energy * pModuleInverse / c_light; |
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| 74 | |
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| 75 | G4double cof1 = fElectroMagCof*pModuleInverse ; |
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| 76 | |
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| 77 | // G4double vDotE = y[3]*Field[3] + y[4]*Field[4] + y[5]*Field[5] ; |
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| 78 | |
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| 79 | |
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| 80 | dydx[0] = y[3]*pModuleInverse ; |
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| 81 | dydx[1] = y[4]*pModuleInverse ; |
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| 82 | dydx[2] = y[5]*pModuleInverse ; |
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| 83 | |
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| 84 | dydx[3] = cof1*(cof2*Field[3] + (y[4]*Field[2] - y[5]*Field[1])) ; |
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| 85 | |
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| 86 | dydx[4] = cof1*(cof2*Field[4] + (y[5]*Field[0] - y[3]*Field[2])) ; |
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| 87 | |
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| 88 | dydx[5] = cof1*(cof2*Field[5] + (y[3]*Field[1] - y[4]*Field[0])) ; |
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| 89 | |
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| 90 | dydx[6] = 0.;//not used |
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| 91 | |
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| 92 | // Lab Time of flight |
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| 93 | dydx[7] = inverse_velocity; |
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| 94 | return ; |
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| 95 | } |
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