1 | #ifndef _H_BeamParticle_
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2 | #define _H_BeamParticle_
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3 |
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4 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * *
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5 | * *
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6 | * --<--<-- A fast simulator --<--<-- *
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7 | * / --<--<-- of particle --<--<-- *
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8 | * ----HECTOR----< *
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9 | * \ -->-->-- transport through -->-->-- *
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10 | * -->-->-- generic beamlines -->-->-- *
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11 | * *
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12 | * JINST 2:P09005 (2007) *
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13 | * X Rouby, J de Favereau, K Piotrzkowski (CP3) *
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14 | * http://www.fynu.ucl.ac.be/hector.html *
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15 | * *
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16 | * Center for Cosmology, Particle Physics and Phenomenology *
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17 | * Universite catholique de Louvain *
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18 | * Louvain-la-Neuve, Belgium *
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19 | * *
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20 | * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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21 |
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22 | /// \file H_BeamParticle.h
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23 | /// \brief Class aiming at simulating a particle in the beamline
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24 |
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25 | // from IP to RP, with emission of a photon of defined energy and Q.
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26 | // Units : angles [rad], distances [m], energies [GeV], masses [GeV], c=[1].
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27 | // !!! no comment statement at the end of a #define line !!!
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28 |
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29 | // c++ #includes
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30 | #include <vector>
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31 |
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32 | // ROOT #includes
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33 | #include "TMatrixD.h"
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34 | #include "TVectorD.h"
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35 | #include "TLorentzVector.h"
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36 | #include "TRandom3.h"
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37 |
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38 | // local #includes
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39 | #include "H_Parameters.h"
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40 | #include "H_AbstractBeamLine.h"
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41 | #include "H_OpticalElement.h"
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42 |
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43 | using namespace std;
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44 |
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45 | /// Defines a particle from the beam and its transport through the beamline
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46 | class H_BeamParticle {
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47 |
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48 | public:
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49 | /// Constructors and Destructor
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50 | //@{
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51 | H_BeamParticle();
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52 | H_BeamParticle(const H_BeamParticle&);
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53 | H_BeamParticle(const double, const double);
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54 | H_BeamParticle& operator=(const H_BeamParticle&);
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55 | ~H_BeamParticle() {if(stop_position) delete stop_position; if(!stop_element) delete stop_element; positions.clear();}
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56 | //@}
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57 | /// Smears the (x,y) coordinates of the particle [\f$ \mu m \f$]
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58 | void smearPos(const double dx=SX,const double dy=SY, TRandom* r=gRandom);
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59 | /// Smears the (x,y) angular coordinates of the particle [\f$ \mu rad \f$]
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60 | void smearAng(const double tx=STX, const double ty=STY, TRandom* r=gRandom);
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61 | /// Smears the Energy of the particle [GeV]
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62 | void smearE(const double erre=SBE, TRandom* r=gRandom);
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63 | /// Smears the longitudinal position of the particle [\f$ \mu m \f$]
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64 | void smearS(const double errs=SS, TRandom* r=gRandom);
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65 | /// Sets the energy [GeV].
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66 | void setE(const double);
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67 | /// Sets the particle 4-momentum \f$ P^\mu \f$
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68 | void set4Momentum(const double, const double, const double, const double);
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69 | /// Sets the particle 4-momentum \f$ P^\mu \f$
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70 | void set4Momentum(const TLorentzVector&);
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71 | /// Clears H_BeamParticle::positions and sets the initial one.
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72 | void setPosition(const double , const double , const double , const double , const double );
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73 | /// Returns the particle mass [GeV]
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74 | const double getM() const {return mp;};
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75 | /// Returns the particle charge [e]
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76 | const double getQ() const {return qp;};
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77 | /// Returns the current x coordinate [\f$ \mu \f$m]
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78 | const double getX() const {return fx;};
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79 | /// Returns the current y coordinate [\f$ \mu \f$m]
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80 | const double getY() const {return fy;};
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81 | /// Returns the current s coordinate [m]
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82 | const double getS() const {return fs;};
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83 | /// Returns the current \f$ \theta_x \f$ angular coordinate [\f$ \mu \f$rad]
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84 | const double getTX() const {return thx;};
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85 | /// Returns the current \f$ \theta_y \f$ angular coordinate [\f$ \mu \f$rad]
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86 | const double getTY() const {return thy;};
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87 | /// Returns the current particle energy [GeV]
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88 | const double getE() const {return energy;};
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89 | /// Returns all the positions
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90 | vector<TVectorD> getPositions() const {return positions;};
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91 | const bool isPhysical() const {return isphysical;};
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92 | /// \brief Simulates the emission of a photon in a random direction
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93 | ///
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94 | /// For \f$ p_{1} \rightarrow p_{2} \gamma \f$, kinematics imposes that
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95 | /// \f$ Q^{2} = E^{2}_{\gamma} -p^{2}_{1} -p^{2}_{2} + 2p_{1}p_{2} cos(\theta) \f$ where \f$ \theta \f$ is the particle scattering angle and \f$ p_{i} = \|\vec{p_{i}}\| \f$. <BR>
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96 | /// So, \f$ Q^{2}_{min} = E^{2}_{\gamma} - (p_{1}+p_{2})^{2} \f$ and \f$ Q^{2}_{max} = E^{2}_{\gamma} - (p_{1}-p_{2})^{2} \f$.<BR>
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97 | /// As \f$ E^{2}_{\gamma} - (p_{1}-p_{2})^{2} \f$ could be numerically instable, we use here another form of this formula : <BR>
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98 | /// \f$ Q^{2}_{max} = -2 * \big( \frac{M_{p} E_{\gamma}}{p_{1}+p_{2}} \big) \big[ 1 + \frac{E^{2}_{1} + E^{2}_{2} - M^{2}_{p} }{ E_{1} E_{2} + p_{1} p_{2}} \big] \f$
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99 | //@{
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100 | void emitGamma(const double gee, const double gq2, const double phimin=0, const double phimax=2*TMath::Pi());
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101 | //@}
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102 | /// uses Pythia to generate some inelastic pp->pX collision as background
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103 | void doInelastic();
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104 | /// \brief Propagates the particule across the beamline until the s coordinate is reached
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105 | ///
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106 | /// Caution : "computePath" should be used before any "propagate" call <BR>
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107 | /// Caution : "stopped" is not included in "propagate" : please run it afterward if needed
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108 | void propagate(const double ) ;
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109 | /// Propagates the particle accross the beamline until a given element
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110 | void propagate(const H_AbstractBeamLine *, const H_OpticalElement *);
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111 | /// Propagates the particle accross the beamline until a given element
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112 | void propagate(const H_AbstractBeamLine *, const string&);
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113 | /// Propagates the particle until the end of the beamline
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114 | void propagate(const H_AbstractBeamLine *);
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115 | /// Returns the phase vector of the particle
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116 | const TMatrixD * getV() const;
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117 | /// Returns the current phase vector of the particle (in H_BeamParticle::positions)
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118 | const TVectorD * getPosition(const int ) const;
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119 | /// Prints the properties of the particle
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120 | void printProperties() const {cout << *this; return;};
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121 | /// Prints the phase vector of the particle
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122 | void printV() const;
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123 | /// Returns the element where the particle has been stopped
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124 | const H_OpticalElement * getStoppingElement() const;
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125 | /// Checks if the particle has been stopped in any element of the beamline
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126 | const bool stopped(const H_AbstractBeamLine *);
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127 | /// Returns the StopPosition vector
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128 | inline const TVectorD * getStopPosition() const { return stop_position; };
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129 | // returns (-1,-1,-1,-1,-1) if not stopped (and then hasstopped is false)
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130 | /// Shows all the vectors \f$ (x, \theta_x, y, \theta_y ,s) \f$ in H_BeamParticle::positions
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131 | void showPositions() const;
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132 | /// Returns the particle path in the beamline
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133 | TGraph * getPath(const int , const int ) const;
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134 | void getPath(const int , const string& ) const;
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135 | /// Computes the position of the particle at the end of each element of the beam.
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136 | void computePath(const H_AbstractBeamLine * beam, const bool NonLinear=true);
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137 | /// Computes the position of the particle at the end of each element of the beam.
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138 | void computePath(const H_AbstractBeamLine & beam, const bool NonLinear=true);
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139 | /// Clears H_BeamParticle::positions but keeps the initial vector.
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140 | void resetPath();
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141 |
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142 | private:
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143 | void init();
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144 | /// Particle mass [GeV]
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145 | double mp;
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146 | /// Particle charge [e]
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147 | double qp;
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148 | /// Longitudinal co-moving coordinate [m]
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149 | double fs;
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150 | /// Transverse (horizontal) coordinate [m]
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151 | double fx;
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152 | /// Transverse (vertical) coordinate [m]
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153 | double fy;
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154 | /// Direction of the 3-momentum in the horizontal plane [rad]
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155 | double thx;
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156 | /// Direction of the 3-momentum in the vertical plane [rad]
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157 | double thy;
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158 | /// Kinetic energy of the particle [GeV]
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159 | double energy;
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160 | /// True if the particle has stopped (i.e. : if the particle transverse position has been out of any optics element aperture). <BR> See H_BeamParticle::stopped method. <BR>Default = false.
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161 | bool hasstopped;
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162 | /// True if the particle has lost some (E,Q), i.e. if H_BeamParticle::emitGamma was used. Default = false.
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163 | bool hasemitted;
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164 | /// False if the particle has emitted a photon with impossible (E,Q). Default = true.
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165 | bool isphysical;
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166 | /// Vector (x,tx,y,ty,s) where the particle has stopped.
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167 | TVectorD * stop_position;
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168 | /// Element of the beamline (H_OpticalElement) where the particle has stopped.
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169 | H_OpticalElement * stop_element;
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170 | /// List of (x,tx,y,ty,s) vectors, after each optical element of the beam
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171 | vector<TVectorD> positions; // vector (x,tx,y,ty,s) after each optical element of the beam ([m],[rad],[m],[rad],[m])
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172 | /// Adds a new vector (x,tx,y,ty,s) at the end of H_BeamParticle::positions
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173 | void addPosition(const double , const double , const double , const double , const double );
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174 |
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175 | friend std::ostream& operator<< (std::ostream& os, const H_BeamParticle& p);
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176 | };
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177 | #endif
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