92 lines
3.3 KiB
C++
92 lines
3.3 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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// $Id$
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// GEANT4 tag $Name: $
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//
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//
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// This is the standard right-hand side for equation of motion.
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//
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// The only case another is required is when using a moving reference
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// frame ... or extending the class to include additional Forces,
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// eg an electric field
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//
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// 10.11.98 V.Grichine
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//
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// -------------------------------------------------------------------
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#include "LEMuSREqMagElectricField.hh"
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#include "globals.hh"
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void
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LEMuSREqMagElectricField::SetChargeMomentumMass(G4double particleCharge, // e+ units
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G4double,
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G4double particleMass)
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{
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fElectroMagCof = eplus*particleCharge*c_light ;
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fMassCof = particleMass*particleMass ;
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}
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void
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LEMuSREqMagElectricField::EvaluateRhsGivenB(const G4double y[],
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const G4double Field[],
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G4double dydx[] ) const
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{
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// Components of y:
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// 0-2 dr/ds,
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// 3-5 dp/ds - momentum derivatives
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G4double pSquared = y[3]*y[3] + y[4]*y[4] + y[5]*y[5] ;
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G4double Energy = sqrt( pSquared + fMassCof );
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G4double cof2 = Energy/c_light ;
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G4double pModuleInverse = 1.0/sqrt(pSquared) ;
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// G4double inverse_velocity = Energy * c_light * pModuleInverse;
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G4double inverse_velocity = Energy * pModuleInverse / c_light;
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G4double cof1 = fElectroMagCof*pModuleInverse ;
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// G4double vDotE = y[3]*Field[3] + y[4]*Field[4] + y[5]*Field[5] ;
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dydx[0] = y[3]*pModuleInverse ;
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dydx[1] = y[4]*pModuleInverse ;
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dydx[2] = y[5]*pModuleInverse ;
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dydx[3] = cof1*(cof2*Field[3] + (y[4]*Field[2] - y[5]*Field[1])) ;
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dydx[4] = cof1*(cof2*Field[4] + (y[5]*Field[0] - y[3]*Field[2])) ;
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dydx[5] = cof1*(cof2*Field[5] + (y[3]*Field[1] - y[4]*Field[0])) ;
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// Lab Time of flight
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dydx[7] = inverse_velocity;
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return ;
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}
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