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25 //
26 // G4ParticleGun class implementation
27 //
28 // Author: Makoto Asai, 1997
29 // --------------------------------------------------------------------
30
31 #include "G4ParticleGun.hh"
32 #include "G4SystemOfUnits.hh"
33 #include "G4PrimaryParticle.hh"
34 #include "G4ParticleGunMessenger.hh"
35 #include "G4Event.hh"
36 #include "G4ios.hh"
37
38 G4ParticleGun::G4ParticleGun()
39 {
40 SetInitialValues();
41 }
42
43 G4ParticleGun::G4ParticleGun(G4int numberofparticles)
44 {
45 SetInitialValues();
46 NumberOfParticlesToBeGenerated = numberofparticles;
47 }
48
49 G4ParticleGun::G4ParticleGun(G4ParticleDefinition* particleDef,
50 G4int numberofparticles)
51 {
52 SetInitialValues();
53 NumberOfParticlesToBeGenerated = numberofparticles;
54 SetParticleDefinition( particleDef );
55 }
56
57 void G4ParticleGun::SetInitialValues()
58 {
59 NumberOfParticlesToBeGenerated = 1;
60 particle_definition = nullptr;
61 G4ThreeVector zero;
62 particle_momentum_direction = (G4ParticleMomentum)zero;
63 particle_energy = 0.0;
64 particle_momentum = 0.0;
65 particle_position = zero;
66 particle_time = 0.0;
67 particle_polarization = zero;
68 particle_charge = 0.0;
69 theMessenger = new G4ParticleGunMessenger(this);
70 }
71
72 G4ParticleGun::~G4ParticleGun()
73 {
74 delete theMessenger;
75 }
76
77 void G4ParticleGun::
78 SetParticleDefinition(G4ParticleDefinition* aParticleDefinition)
79 {
80 if(aParticleDefinition == nullptr)
81 {
82 G4Exception("G4ParticleGun::SetParticleDefinition()", "Event0101",
83 FatalException, "Null pointer is given.");
84 }
85 if(aParticleDefinition->IsShortLived())
86 {
87 if(aParticleDefinition->GetDecayTable() == nullptr)
88 {
89 G4ExceptionDescription ED;
90 ED << "G4ParticleGun does not support shooting a short-lived "
91 << "particle without a valid decay table." << G4endl;
92 ED << "G4ParticleGun::SetParticleDefinition for "
93 << aParticleDefinition->GetParticleName() << " is ignored." << G4endl;
94 G4Exception("G4ParticleGun::SetParticleDefinition()", "Event0102",
95 JustWarning, ED);
96 return;
97 }
98 }
99 particle_definition = aParticleDefinition;
100 particle_charge = particle_definition->GetPDGCharge();
101 if(particle_momentum>0.0)
102 {
103 G4double mass = particle_definition->GetPDGMass();
104 particle_energy =
105 std::sqrt(particle_momentum*particle_momentum+mass*mass)-mass;
106 }
107 }
108
109 void G4ParticleGun::SetParticleEnergy(G4double aKineticEnergy)
110 {
111 particle_energy = aKineticEnergy;
112 if(particle_momentum>0.0)
113 {
114 if(particle_definition != nullptr)
115 {
116 G4cout << "G4ParticleGun::" << particle_definition->GetParticleName()
117 << G4endl;
118 }
119 else
120 {
121 G4cout << "G4ParticleGun::" << " " << G4endl;
122 }
123 G4cout << " was defined in terms of Momentum: "
124 << particle_momentum/GeV << "GeV/c" << G4endl;
125 G4cout << " is now defined in terms of KineticEnergy: "
126 << particle_energy/GeV << "GeV" << G4endl;
127 particle_momentum = 0.0;
128 }
129 }
130
131 void G4ParticleGun::SetParticleMomentum(G4double aMomentum)
132 {
133 if(particle_energy>0.0)
134 {
135 if(particle_definition != nullptr)
136 {
137 G4cout << "G4ParticleGun::" << particle_definition->GetParticleName()
138 << G4endl;
139 }
140 else
141 {
142 G4cout << "G4ParticleGun::" << " " << G4endl;
143 }
144 G4cout << " was defined in terms of KineticEnergy: "
145 << particle_energy/GeV << "GeV" << G4endl;
146 G4cout << " is now defined in terms Momentum: "
147 << aMomentum/GeV << "GeV/c" << G4endl;
148 }
149 if(particle_definition == nullptr)
150 {
151 G4cout << "Particle Definition not defined yet for G4ParticleGun"
152 << G4endl;
153 G4cout << "Zero Mass is assumed" << G4endl;
154 particle_momentum = aMomentum;
155 particle_energy = aMomentum;
156 }
157 else
158 {
159 G4double mass = particle_definition->GetPDGMass();
160 particle_momentum = aMomentum;
161 particle_energy =
162 std::sqrt(particle_momentum*particle_momentum+mass*mass)-mass;
163 }
164 }
165
166 void G4ParticleGun::SetParticleMomentum(G4ParticleMomentum aMomentum)
167 {
168 if(particle_energy>0.0)
169 {
170 if(particle_definition != nullptr)
171 {
172 G4cout << "G4ParticleGun::" << particle_definition->GetParticleName()
173 << G4endl;
174 }
175 else
176 {
177 G4cout << "G4ParticleGun::" << " " << G4endl;
178 }
179 G4cout << " was defined in terms of KineticEnergy: "
180 << particle_energy/GeV << "GeV" << G4endl;
181 G4cout << " is now defined in terms Momentum: "
182 << aMomentum.mag()/GeV << "GeV/c" << G4endl;
183 }
184 if(particle_definition == nullptr)
185 {
186 G4cout << "Particle Definition not defined yet for G4ParticleGun"
187 << G4endl;
188 G4cout << "Zero Mass is assumed" << G4endl;
189 particle_momentum_direction = aMomentum.unit();
190 particle_momentum = aMomentum.mag();
191 particle_energy = aMomentum.mag();
192 }
193 else
194 {
195 G4double mass = particle_definition->GetPDGMass();
196 particle_momentum = aMomentum.mag();
197 particle_momentum_direction = aMomentum.unit();
198 particle_energy =
199 std::sqrt(particle_momentum*particle_momentum+mass*mass)-mass;
200 }
201 }
202
203 void G4ParticleGun::GeneratePrimaryVertex(G4Event* evt)
204 {
205 if(particle_definition == nullptr)
206 {
207 G4ExceptionDescription ED;
208 ED << "Particle definition is not defined." << G4endl;
209 ED << "G4ParticleGun::SetParticleDefinition() has to be invoked beforehand."
210 << G4endl;
211 G4Exception("G4ParticleGun::GeneratePrimaryVertex()", "Event0109",
212 FatalException, ED);
213 return;
214 }
215
216 // Create a new vertex
217 //
218 auto* vertex =
219 new G4PrimaryVertex(particle_position,particle_time);
220
221 // Create new primaries and set them to the vertex
222 //
223 G4double mass = particle_definition->GetPDGMass();
224 for( G4int i=0; i<NumberOfParticlesToBeGenerated; ++i )
225 {
226 auto* particle =
227 new G4PrimaryParticle(particle_definition);
228 particle->SetKineticEnergy( particle_energy );
229 particle->SetMass( mass );
230 particle->SetMomentumDirection( particle_momentum_direction );
231 particle->SetCharge( particle_charge );
232 particle->SetPolarization(particle_polarization.x(),
233 particle_polarization.y(),
234 particle_polarization.z());
235 particle->SetWeight( particle_weight );
236 vertex->SetPrimary( particle );
237 }
238 evt->AddPrimaryVertex( vertex );
239 }
240