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25 //
26 // J.M. Quesada (August2008). Based on:
27 //
28 // Hadronic Process: Nuclear De-excitations
29 // by V. Lara (Oct 1998)
30 //
31 // Modif (03 September 2008) by J. M. Quesada for external choice of inverse
32 // cross section option
33 // JMQ (06 September 2008) Also external choices have been added for
34 // superimposed Coulomb barrier (if useSICB is set true, by default is false)
35 //
36 // JMQ (14 february 2009) bug fixed in emission width: hbarc instead of
37 // hbar_Planck in the denominator
38 //
39 // V.Ivanchenko general clean-up since 2010
40 //
41 #include "G4EvaporationProbability.hh"
42 #include "G4NuclearLevelData.hh"
43 #include "G4VCoulombBarrier.hh"
44 #include "G4PhysicalConstants.hh"
45 #include "G4SystemOfUnits.hh"
46 #include "G4PairingCorrection.hh"
47 #include "G4NucleiProperties.hh"
48 #include "G4KalbachCrossSection.hh"
49 #include "G4ChatterjeeCrossSection.hh"
50 #include "G4InterfaceToXS.hh"
51 #include "G4IsotopeList.hh"
52 #include "G4Neutron.hh"
53 #include "G4Proton.hh"
54 #include "G4Deuteron.hh"
55 #include "G4Triton.hh"
56 #include "G4He3.hh"
57 #include "G4Alpha.hh"
58 #include "Randomize.hh"
59 #include "G4Exp.hh"
60 #include "G4Log.hh"
61 #include "G4Pow.hh"
62
63 namespace
64 {
65 const G4double explim = 160.;
66 }
67
68 G4EvaporationProbability::G4EvaporationProbability(G4int anA, G4int aZ,
69 G4double aGamma)
70 : G4VEmissionProbability(aZ, anA), fGamma(aGamma)
71 {
72 resA13 = lastA = muu = freeU = a0 = a1 = delta0 = delta1 = 0.0;
73 pcoeff = fGamma*pEvapMass*CLHEP::millibarn
74 /((CLHEP::pi*CLHEP::hbarc)*(CLHEP::pi*CLHEP::hbarc));
75
76 if (1 == theZ && 1 == theA) { index = 1; }
77 else if (1 == theZ && 2 == theA) { index = 2; }
78 else if (1 == theZ && 3 == theA) { index = 3; }
79 else if (2 == theZ && 3 == theA) { index = 4; }
80 else if (2 == theZ && 4 == theA) { index = 5; }
81
82 if (OPTxs == 1) {
83 const G4ParticleDefinition* part = nullptr;
84 if (index == 1) { part = G4Proton::Proton(); }
85 else if (index == 2) { part = G4Deuteron::Deuteron(); }
86 else if (index == 3) { part = G4Triton::Triton(); }
87 else if (index == 4) { part = G4He3::He3(); }
88 else if (index == 5) { part = G4Alpha::Alpha(); }
89 else { part = G4Neutron::Neutron(); }
90 fXSection = new G4InterfaceToXS(part, index);
91 }
92
93 if (0 == aZ) {
94 ResetIntegrator(30, 0.15*CLHEP::MeV, 0.02);
95 } else {
96 ResetIntegrator(30, 0.25*CLHEP::MeV, 0.03);
97 }
98 }
99
100 G4EvaporationProbability::~G4EvaporationProbability()
101 {
102 delete fXSection;
103 }
104
105 G4double G4EvaporationProbability::CalcAlphaParam(const G4Fragment&)
106 {
107 return 1.0;
108 }
109
110 G4double G4EvaporationProbability::CalcBetaParam(const G4Fragment&)
111 {
112 return 1.0;
113 }
114
115 G4double G4EvaporationProbability::TotalProbability(
116 const G4Fragment& fragment, G4double minEnergy, G4double maxEnergy,
117 G4double CB, G4double exEnergy)
118 {
119 G4int fragA = fragment.GetA_asInt();
120 G4int fragZ = fragment.GetZ_asInt();
121 freeU = exEnergy;
122 a0 = pNuclearLevelData->GetLevelDensity(fragZ, fragA, freeU);
123 delta0 = pNuclearLevelData->GetPairingCorrection(fragZ, fragA);
124 delta1 = pNuclearLevelData->GetPairingCorrection(resZ, resA);
125 resA13 = pG4pow->Z13(resA);
126 /*
127 G4cout << "G4EvaporationProbability: Z= " << theZ << " A= " << theA
128 << " resZ= " << resZ << " resA= " << resA
129 << " fragZ= " << fragZ << " fragA= " << fragA
130 << "\n freeU= " << freeU
131 << " a0= " << a0 << " OPT= " << OPTxs << " emin= "
132 << minEnergy << " emax= " << maxEnergy
133 << " CB= " << CB << G4endl;
134 */
135 if (OPTxs==0) {
136
137 G4double SystemEntropy = 2.0*std::sqrt(a0*freeU);
138 const G4double RN2 = 2.25*CLHEP::fermi*CLHEP::fermi
139 /(CLHEP::twopi*CLHEP::hbar_Planck*hbar_Planck);
140
141 G4double Alpha = CalcAlphaParam(fragment);
142 G4double Beta = CalcBetaParam(fragment);
143
144 // to be checked where to use a0, where - a1
145 a1 = pNuclearLevelData->GetLevelDensity(resZ,resA,freeU);
146 G4double GlobalFactor = fGamma*Alpha*pEvapMass*RN2*resA13*resA13/(a1*a1);
147
148 G4double maxea = maxEnergy*a1;
149 G4double Term1 = Beta*a1 - 1.5 + maxea;
150 G4double Term2 = (2.0*Beta*a1-3.0)*std::sqrt(maxea) + 2*maxea;
151
152 G4double ExpTerm1 = (SystemEntropy <= explim) ? G4Exp(-SystemEntropy) : 0.0;
153
154 G4double ExpTerm2 = 2.*std::sqrt(maxea) - SystemEntropy;
155 ExpTerm2 = std::min(ExpTerm2, explim);
156 ExpTerm2 = G4Exp(ExpTerm2);
157
158 pProbability = GlobalFactor*(Term1*ExpTerm1 + Term2*ExpTerm2);
159
160 } else {
161 // if Coulomb barrier cutoff is superimposed for all cross sections
162 // then the limit is the Coulomb Barrier
163 pProbability = IntegrateProbability(minEnergy, maxEnergy, CB);
164 }
165 /*
166 G4cout << "TotalProbability: Emin=" << minEnergy << " Emax= " << maxEnergy
167 << " CB= " << CB << " prob=" << pProbability << G4endl;
168 */
169 return pProbability;
170 }
171
172 G4double G4EvaporationProbability::ComputeProbability(G4double K, G4double CB)
173 {
174 // abnormal case - should never happens
175 if(pMass < pEvapMass + pResMass + K) { return 0.0; }
176
177 G4double pEvapM2 = pEvapMass*pEvapMass;
178 G4double mres = std::sqrt(pMass*pMass + pEvapM2 - 2.*pMass*(pEvapMass + K));
179
180 G4double excRes = mres - pResMass;
181 if (excRes < 0.0) { return 0.0; }
182 G4double K1 = (pMass*(K + pEvapMass) - pEvapM2)/mres - pEvapMass;
183 K1 = std::max(K1, 0.0);
184 G4double xs = CrossSection(K1, CB);
185 if (xs <= 0.0) { return 0.0; }
186
187 a1 = pNuclearLevelData->GetLevelDensity(resZ, resA, excRes);
188 G4double E0 = std::max(freeU - delta0, 0.0);
189 G4double E1 = std::max(excRes - delta1, 0.0);
190 G4double prob = pcoeff*G4Exp(2.0*(std::sqrt(a1*E1) - std::sqrt(a0*E0)))*K1*xs;
191 return prob;
192 }
193
194 G4double
195 G4EvaporationProbability::CrossSection(G4double K, G4double CB)
196 {
197 // compute power once
198 if (OPTxs > 1 && 0 < index && resA != lastA) {
199 lastA = resA;
200 muu = G4KalbachCrossSection::ComputePowerParameter(resA, index);
201 }
202 if (OPTxs == 1) {
203 recentXS = fXSection->GetElementCrossSection(K, resZ)/CLHEP::millibarn;
204
205 } else if (OPTxs == 2) {
206 recentXS = G4ChatterjeeCrossSection::ComputeCrossSection(K, CB, resA13, muu,
207 index, theZ, resA);
208 } else if (OPTxs == 3) {
209 recentXS = G4KalbachCrossSection::ComputeCrossSection(K, CB, resA13, muu,
210 index, theZ, theA, resA);
211 }
212 return recentXS;
213 }
214