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35 // 35 //
36 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% << 36 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
37 // 37 //
38 // MODULE: G4EMDissociationCrossSection.cc 38 // MODULE: G4EMDissociationCrossSection.cc
39 // 39 //
40 // Version: B.1 40 // Version: B.1
41 // Date: 15/04/04 41 // Date: 15/04/04
42 // Author: P R Truscott 42 // Author: P R Truscott
43 // Organisation: QinetiQ Ltd, UK 43 // Organisation: QinetiQ Ltd, UK
44 // Customer: ESA/ESTEC, NOORDWIJK 44 // Customer: ESA/ESTEC, NOORDWIJK
45 // Contract: 17191/03/NL/LvH 45 // Contract: 17191/03/NL/LvH
46 // 46 //
47 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% << 47 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
48 // 48 //
49 // CHANGE HISTORY 49 // CHANGE HISTORY
50 // -------------- 50 // --------------
51 // 51 //
52 // 17 October 2003, P R Truscott, QinetiQ Ltd, 52 // 17 October 2003, P R Truscott, QinetiQ Ltd, UK
53 // Created. 53 // Created.
54 // 54 //
55 // 15 March 2004, P R Truscott, QinetiQ Ltd, U 55 // 15 March 2004, P R Truscott, QinetiQ Ltd, UK
56 // Beta release 56 // Beta release
57 // 57 //
58 // 30 May 2005, J.P. Wellisch removed a compil << 58 // 30. May 2005, J.P. Wellisch removed a compilation warning on gcc 3.4 for gant4 7.1.
59 // geant4 7.1. <<
60 // 09 November 2010, V.Ivanchenko make class a <<
61 // set cross section for Hyd <<
62 // 59 //
63 // 17 August 2011, V.Ivanchenko, provide migra << 60 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
64 // sections considering this c << 61 ////////////////////////////////////////////////////////////////////////////////
65 // <<
66 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% <<
67 ////////////////////////////////////////////// <<
68 // 62 //
69 #include "G4EMDissociationCrossSection.hh" 63 #include "G4EMDissociationCrossSection.hh"
70 #include "G4PhysicalConstants.hh" << 64 #include "G4PhysicsFreeVector.hh"
71 #include "G4SystemOfUnits.hh" <<
72 #include "G4ParticleTable.hh" 65 #include "G4ParticleTable.hh"
73 #include "G4IonTable.hh" 66 #include "G4IonTable.hh"
74 #include "G4HadTmpUtil.hh" <<
75 #include "globals.hh" 67 #include "globals.hh"
76 #include "G4NistManager.hh" << 68 ////////////////////////////////////////////////////////////////////////////////
77 << 69 //
78 <<
79 G4EMDissociationCrossSection::G4EMDissociation 70 G4EMDissociationCrossSection::G4EMDissociationCrossSection ()
80 : G4VCrossSectionDataSet("Electromagnetic dis <<
81 { 71 {
82 // This function makes use of the class whic << 72 //
83 // spectrum, G4EMDissociationSpectrum. << 73 //
84 << 74 // This function makes use of the class which can sample the virtual photon
>> 75 // spectrum, G4EMDissociationSpectrum.
>> 76 //
85 thePhotonSpectrum = new G4EMDissociationSpec 77 thePhotonSpectrum = new G4EMDissociationSpectrum();
86 << 78 //
87 // Define other constants. << 79 //
88 << 80 // Define other constants.
>> 81 //
89 r0 = 1.18 * fermi; 82 r0 = 1.18 * fermi;
90 J = 36.8 * MeV; 83 J = 36.8 * MeV;
91 Qprime = 17.0 * MeV; 84 Qprime = 17.0 * MeV;
92 epsilon = 0.0768; 85 epsilon = 0.0768;
93 xd = 0.25; 86 xd = 0.25;
94 } 87 }
95 << 88 ////////////////////////////////////////////////////////////////////////////////
96 ////////////////////////////////////////////// << 89 //
97 <<
98 G4EMDissociationCrossSection::~G4EMDissociatio 90 G4EMDissociationCrossSection::~G4EMDissociationCrossSection()
99 { 91 {
100 delete thePhotonSpectrum; 92 delete thePhotonSpectrum;
101 } 93 }
102 ////////////////////////////////////////////// << 94 ////////////////////////////////////////////////////////////////////////////////
103 // 95 //
104 G4bool << 96 G4bool G4EMDissociationCrossSection::IsApplicable
105 G4EMDissociationCrossSection::IsElementApplica << 97 (const G4DynamicParticle *theDynamicParticle, const G4Element* theElement)
106 G4int /*ZZ*/, const G4Material*) <<
107 { 98 {
108 // 99 //
>> 100 //
109 // The condition for the applicability of this 101 // The condition for the applicability of this class is that the projectile
110 // must be an ion and the target must have mor 102 // must be an ion and the target must have more than one nucleon. In reality
111 // the value of A for either the projectile or 103 // the value of A for either the projectile or target could be much higher,
112 // since for cases where both he projectile an 104 // since for cases where both he projectile and target are medium to small
113 // Z, the probability of the EMD process is, I 105 // Z, the probability of the EMD process is, I think, VERY small.
114 // 106 //
115 if (G4ParticleTable::GetParticleTable()->Get << 107 if (G4ParticleTable::GetParticleTable()->GetIonTable()->
>> 108 IsIon(theDynamicParticle->GetDefinition()) && theElement->GetN() > 1.0)
116 return true; 109 return true;
117 } else { << 110 else
118 return false; 111 return false;
119 } <<
120 } 112 }
121 << 113 ////////////////////////////////////////////////////////////////////////////////
122 ////////////////////////////////////////////// <<
123 // 114 //
124 G4double G4EMDissociationCrossSection::GetElem << 115 G4double G4EMDissociationCrossSection::GetCrossSection
125 (const G4DynamicParticle* theDynamicParticle << 116 (const G4DynamicParticle *theDynamicParticle, const G4Element* theElement,
126 const G4Material*) << 117 G4double )
127 { 118 {
128 // VI protection for Hydrogen << 119 //
129 if(1 >= Z) { return 0.0; } << 120 //
130 << 121 // Get relevant information about the projectile and target (A, Z) and
131 // Zero cross-section for particles with kin << 122 // velocity of the projectile.
132 // possible abort signal from bad arithmetic << 123 //
133 if ( theDynamicParticle->GetKineticEnergy() << 124 G4ParticleDefinition *definitionP = theDynamicParticle->GetDefinition();
134 <<
135 // <<
136 // Get relevant information about the projec <<
137 // velocity of the projectile. <<
138 // <<
139 const G4ParticleDefinition *definitionP = th <<
140 G4double AP = definitionP->GetBaryonNumber 125 G4double AP = definitionP->GetBaryonNumber();
141 G4double ZP = definitionP->GetPDGCharge(); 126 G4double ZP = definitionP->GetPDGCharge();
142 G4double b = theDynamicParticle->GetBeta( << 127 G4double b = theDynamicParticle->Get4Momentum().beta();
143 if (b <= 0.0 && b >= 1.0) { return 0.0; } << 128 // G4double bsq = b * b;
144 129
145 G4double AT = G4NistManager::Instance()->G << 130 G4double AT = theElement->GetN();
146 G4double ZT = (G4double)Z; << 131 G4double ZT = theElement->GetZ();
147 G4double bmin = thePhotonSpectrum->GetCloses 132 G4double bmin = thePhotonSpectrum->GetClosestApproach(AP, ZP, AT, ZT, b);
148 // << 133 //
149 // << 134 //
150 // Calculate the cross-section for the proje << 135 // Calculate the cross-section for the projectile and then the target. The
151 // information is returned in a G4PhysicsFre << 136 // information is returned in a G4PhysicsFreeVector, which separates out the
152 // cross-sections for the E1 and E2 moments << 137 // cross-sections for the E1 and E2 moments of the virtual photon field, and
153 // the energies (GDR and GQR). << 138 // the energies (GDR and GQR).
154 // << 139 //
155 G4PhysicsFreeVector *theProjectileCrossSecti << 140 G4PhysicsFreeVector *theProjectileCrossSections =
156 GetCrossSectionForProjectile (AP, ZP, AT, 141 GetCrossSectionForProjectile (AP, ZP, AT, ZT, b, bmin);
157 G4double crossSection = 142 G4double crossSection =
158 (*theProjectileCrossSections)[0]+(*theProj 143 (*theProjectileCrossSections)[0]+(*theProjectileCrossSections)[1];
159 delete theProjectileCrossSections; 144 delete theProjectileCrossSections;
160 G4PhysicsFreeVector *theTargetCrossSections << 145 G4PhysicsFreeVector *theTargetCrossSections =
161 GetCrossSectionForTarget (AP, ZP, AT, ZT, 146 GetCrossSectionForTarget (AP, ZP, AT, ZT, b, bmin);
162 crossSection += << 147 crossSection +=
163 (*theTargetCrossSections)[0]+(*theTargetCr 148 (*theTargetCrossSections)[0]+(*theTargetCrossSections)[1];
164 delete theTargetCrossSections; 149 delete theTargetCrossSections;
>> 150
165 return crossSection; 151 return crossSection;
166 } 152 }
167 ////////////////////////////////////////////// 153 ////////////////////////////////////////////////////////////////////////////////
168 // 154 //
169 G4PhysicsFreeVector * 155 G4PhysicsFreeVector *
170 G4EMDissociationCrossSection::GetCrossSectionF << 156 G4EMDissociationCrossSection::GetCrossSectionForProjectile (G4double AP,
171 G4double ZP, G4double /* AT */, G4double ZT, 157 G4double ZP, G4double /* AT */, G4double ZT, G4double b, G4double bmin)
172 { 158 {
173 // 159 //
174 // 160 //
175 // Use Wilson et al's approach to calculate th 161 // Use Wilson et al's approach to calculate the cross-sections due to the E1
176 // and E2 moments of the field at the giant di 162 // and E2 moments of the field at the giant dipole and quadrupole resonances
177 // respectively, Note that the algorithm is t 163 // respectively, Note that the algorithm is traditionally applied to the
178 // EMD break-up of the projectile in the field 164 // EMD break-up of the projectile in the field of the target, as is implemented
179 // here. 165 // here.
180 // 166 //
181 // Initialise variables and calculate the ener 167 // Initialise variables and calculate the energies for the GDR and GQR.
182 // 168 //
183 G4double AProot3 = G4Pow::GetInstance()->A13 << 169 G4double AProot3 = std::pow(AP,1.0/3.0);
184 G4double u = 3.0 * J / Qprime / AProot 170 G4double u = 3.0 * J / Qprime / AProot3;
185 G4double R0 = r0 * AProot3; 171 G4double R0 = r0 * AProot3;
186 G4double E_GDR = hbarc / std::sqrt(0.7*amu_ 172 G4double E_GDR = hbarc / std::sqrt(0.7*amu_c2*R0*R0/8.0/J*
187 (1.0 + u - (1.0 + epsilon + 3.0*u)/(1.0 + 173 (1.0 + u - (1.0 + epsilon + 3.0*u)/(1.0 + epsilon + u)*epsilon));
188 G4double E_GQR = 63.0 * MeV / AProot3; 174 G4double E_GQR = 63.0 * MeV / AProot3;
189 // 175 //
190 // 176 //
191 // Determine the virtual photon spectra at the 177 // Determine the virtual photon spectra at these energies.
192 // 178 //
193 G4double ZTsq = ZT * ZT; 179 G4double ZTsq = ZT * ZT;
194 G4double nE1 = ZTsq * 180 G4double nE1 = ZTsq *
195 thePhotonSpectrum->GetGeneralE1Spectrum(E_ 181 thePhotonSpectrum->GetGeneralE1Spectrum(E_GDR, b, bmin);
196 G4double nE2 = ZTsq * 182 G4double nE2 = ZTsq *
197 thePhotonSpectrum->GetGeneralE2Spectrum(E_ 183 thePhotonSpectrum->GetGeneralE2Spectrum(E_GQR, b, bmin);
198 // 184 //
199 // 185 //
200 // Now calculate the cross-section of the proj 186 // Now calculate the cross-section of the projectile for interaction with the
201 // E1 and E2 fields. 187 // E1 and E2 fields.
202 // 188 //
203 G4double sE1 = 60.0 * millibarn * MeV * (AP- 189 G4double sE1 = 60.0 * millibarn * MeV * (AP-ZP)*ZP/AP;
204 G4double sE2 = 0.22 * microbarn / MeV * ZP * 190 G4double sE2 = 0.22 * microbarn / MeV * ZP * AProot3 * AProot3;
205 if (AP > 100.0) sE2 *= 0.9; 191 if (AP > 100.0) sE2 *= 0.9;
206 else if (AP > 40.0) sE2 *= 0.6; 192 else if (AP > 40.0) sE2 *= 0.6;
207 else sE2 *= 0.3; 193 else sE2 *= 0.3;
208 // 194 //
209 // 195 //
210 // ... and multiply with the intensity of the 196 // ... and multiply with the intensity of the virtual photon spectra to get
211 // the probability of interaction. 197 // the probability of interaction.
212 // 198 //
213 G4PhysicsFreeVector *theCrossSectionVector = 199 G4PhysicsFreeVector *theCrossSectionVector = new G4PhysicsFreeVector(2);
214 theCrossSectionVector->PutValue(0, E_GDR, sE 200 theCrossSectionVector->PutValue(0, E_GDR, sE1*nE1);
215 theCrossSectionVector->PutValue(1, E_GQR, sE 201 theCrossSectionVector->PutValue(1, E_GQR, sE2*nE2*E_GQR*E_GQR);
216 << 202
217 return theCrossSectionVector; 203 return theCrossSectionVector;
218 } 204 }
219 <<
220 ////////////////////////////////////////////// 205 ////////////////////////////////////////////////////////////////////////////////
221 // 206 //
222 G4PhysicsFreeVector * 207 G4PhysicsFreeVector *
223 G4EMDissociationCrossSection::GetCrossSectionF << 208 G4EMDissociationCrossSection::GetCrossSectionForTarget (G4double AP,
224 G4double ZP, G4double AT, G4double ZT, G4dou 209 G4double ZP, G4double AT, G4double ZT, G4double b, G4double bmin)
225 { 210 {
226 // 211 //
>> 212 //
227 // This is a cheaky little member function to 213 // This is a cheaky little member function to calculate the probability of
228 // EMD for the target in the field of the proj 214 // EMD for the target in the field of the projectile ... just by reversing the
229 // A and Z's for the participants. 215 // A and Z's for the participants.
230 // 216 //
231 return GetCrossSectionForProjectile (AT, ZT, 217 return GetCrossSectionForProjectile (AT, ZT, AP, ZP, b, bmin);
232 } 218 }
233 <<
234 ////////////////////////////////////////////// 219 ////////////////////////////////////////////////////////////////////////////////
235 // 220 //
236 G4double 221 G4double
237 G4EMDissociationCrossSection::GetWilsonProbabi << 222 G4EMDissociationCrossSection::GetWilsonProbabilityForProtonDissociation
238 << 223 (G4double A, G4double Z)
239 { 224 {
240 // 225 //
>> 226 //
241 // This is a simple algorithm to choose whethe 227 // This is a simple algorithm to choose whether a proton or neutron is ejected
242 // from the nucleus in the EMD interaction. 228 // from the nucleus in the EMD interaction.
243 // 229 //
244 G4double p = 0.0; 230 G4double p = 0.0;
245 if (Z < 2.0) << 231 if (Z < 6.0)
246 p = 0.0; // To avoid to remove one proton <<
247 else if (Z < 6.0) <<
248 p = 0.5; 232 p = 0.5;
249 else if (Z < 8.0) 233 else if (Z < 8.0)
250 p = 0.6; 234 p = 0.6;
251 else if (Z < 14.0) 235 else if (Z < 14.0)
252 p = 0.7; 236 p = 0.7;
253 else 237 else
254 { 238 {
255 G4double p1 = (G4double) Z / (G4double) A; 239 G4double p1 = (G4double) Z / (G4double) A;
256 G4double p2 = 1.95*G4Exp(-0.075*Z); << 240 G4double p2 = 1.95*std::exp(-0.075*Z);
257 if (p1 < p2) p = p1; 241 if (p1 < p2) p = p1;
258 else p = p2; 242 else p = p2;
259 } 243 }
260 244
261 return p; 245 return p;
262 } 246 }
>> 247 ////////////////////////////////////////////////////////////////////////////////
>> 248 //
263 249