source: trunk/source/processes/hadronic/models/de_excitation/gem_evaporation/src/G4GEMProbability.cc @ 1347

Last change on this file since 1347 was 1347, checked in by garnier, 13 years ago

geant4 tag 9.4
File size: 10.3 KB
Line 
1//
2// ********************************************************************
3// * License and Disclaimer                                           *
4// *                                                                  *
5// * The  Geant4 software  is  copyright of the Copyright Holders  of *
6// * the Geant4 Collaboration.  It is provided  under  the terms  and *
7// * conditions of the Geant4 Software License,  included in the file *
8// * LICENSE and available at  http://cern.ch/geant4/license .  These *
9// * include a list of copyright holders.                             *
10// *                                                                  *
11// * Neither the authors of this software system, nor their employing *
12// * institutes,nor the agencies providing financial support for this *
13// * work  make  any representation or  warranty, express or implied, *
14// * regarding  this  software system or assume any liability for its *
15// * use.  Please see the license in the file  LICENSE  and URL above *
16// * for the full disclaimer and the limitation of liability.         *
17// *                                                                  *
18// * This  code  implementation is the result of  the  scientific and *
19// * technical work of the GEANT4 collaboration.                      *
20// * By using,  copying,  modifying or  distributing the software (or *
21// * any work based  on the software)  you  agree  to acknowledge its *
22// * use  in  resulting  scientific  publications,  and indicate your *
23// * acceptance of all terms of the Geant4 Software license.          *
24// ********************************************************************
25//
26// $Id: G4GEMProbability.cc,v 1.15 2010/11/05 14:43:27 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-04-ref-00 $
28//
29//---------------------------------------------------------------------
30//
31// Geant4 class G4GEMProbability
32//
33//
34// Hadronic Process: Nuclear De-excitations
35// by V. Lara (Sept 2001)
36//
37//
38// Hadronic Process: Nuclear De-excitations
39// by V. Lara (Sept 2001)
40//
41// J. M. Quesada : several fixes in total GEM width
42// J. M. Quesada 14/07/2009 bug fixed in total emission width (hbarc)
43// J. M. Quesada (September 2009) several fixes:
44//       -level density parameter of residual calculated at its right excitation energy.
45//       -InitialLeveldensity calculated according to the right conditions of the
46//        initial excited nucleus.
47// J. M. Quesada 19/04/2010 fix in  emission probability calculation.
48// V.Ivanchenko  20/04/2010 added usage of G4Pow and use more safe computation
49// V.Ivanchenko 18/05/2010 trying to speedup the most slow method
50//            by usage of G4Pow, integer Z and A; moved constructor,
51//            destructor and virtual functions to source
52
53#include "G4GEMProbability.hh"
54#include "G4PairingCorrection.hh"
55#include "G4Pow.hh"
56#include "G4IonTable.hh"
57
58G4GEMProbability:: G4GEMProbability() : 
59  theA(0), theZ(0), Spin(0.0), theCoulombBarrierPtr(0),
60  ExcitationEnergies(0), ExcitationSpins(0), ExcitationLifetimes(0), Normalization(1.0)
61{
62  theEvapLDPptr = new G4EvaporationLevelDensityParameter;
63  fG4pow = G4Pow::GetInstance(); 
64  fPairCorr = G4PairingCorrection::GetInstance();
65}
66
67G4GEMProbability:: G4GEMProbability(G4int anA, G4int aZ, G4double aSpin) : 
68  theA(anA), theZ(aZ), Spin(aSpin), theCoulombBarrierPtr(0),
69  ExcitationEnergies(0), ExcitationSpins(0), ExcitationLifetimes(0), Normalization(1.0)
70{
71  theEvapLDPptr = new G4EvaporationLevelDensityParameter;
72  fG4pow = G4Pow::GetInstance(); 
73  fPairCorr = G4PairingCorrection::GetInstance();
74}
75   
76G4GEMProbability::~G4GEMProbability()
77{
78  delete theEvapLDPptr;
79}
80
81G4double G4GEMProbability::CalcAlphaParam(const G4Fragment & ) const 
82{
83  return 1.0;
84}
85
86G4double G4GEMProbability::CalcBetaParam(const G4Fragment & ) const 
87{
88  return 1.0;
89}
90
91G4double G4GEMProbability::CCoeficient(const G4double ) const 
92{
93  return 0.0;
94}
95
96G4double G4GEMProbability::EmissionProbability(const G4Fragment & fragment,
97                                               G4double MaximalKineticEnergy)
98{
99  G4double EmissionProbability = 0.0;
100   
101  if (MaximalKineticEnergy > 0.0 && fragment.GetExcitationEnergy() > 0.0) {
102    G4double CoulombBarrier = GetCoulombBarrier(fragment);
103     
104    EmissionProbability = CalcProbability(fragment,MaximalKineticEnergy,CoulombBarrier);
105    Normalization = EmissionProbability;
106    // Next there is a loop over excited states for this channel summing probabilities
107    if (ExcitationEnergies  &&  ExcitationSpins && ExcitationLifetimes) {
108      G4double SavedSpin = Spin;
109      for (size_t i = 0; i < ExcitationEnergies->size(); ++i) {
110        Spin = ExcitationSpins->operator[](i);
111        // substract excitation energies
112        G4double Tmax = MaximalKineticEnergy - ExcitationEnergies->operator[](i);
113        if (Tmax > 0.0) {
114          G4double width = CalcProbability(fragment,Tmax,CoulombBarrier);
115          //JMQ April 2010 added condition to prevent reported crash
116          // update probability
117          if (width > 0. && 
118              hbar_Planck*fG4pow->logZ(2) < width*ExcitationLifetimes->operator[](i)) {
119            EmissionProbability += width;
120          }
121        }
122      }
123      // Restore Spin
124      Spin = SavedSpin;
125    }
126  }
127  return EmissionProbability;
128}
129
130
131G4double G4GEMProbability::CalcProbability(const G4Fragment & fragment, 
132                                           G4double MaximalKineticEnergy,
133                                           G4double V)
134
135// Calculate integrated probability (width) for evaporation channel
136{
137  G4int A = fragment.GetA_asInt();
138  G4int Z = fragment.GetZ_asInt();
139
140  G4int ResidualA = A - theA;
141  G4int ResidualZ = Z - theZ;
142  G4double U = fragment.GetExcitationEnergy();
143 
144  G4double NuclearMass = fragment.ComputeGroundStateMass(theZ, theA);
145 
146  G4double Alpha = CalcAlphaParam(fragment);
147  G4double Beta = CalcBetaParam(fragment);
148   
149  //                       ***RESIDUAL***
150  //JMQ (September 2009) the following quantities refer to the RESIDUAL:
151 
152  G4double delta0 = fPairCorr->GetPairingCorrection(ResidualA, ResidualZ); 
153 
154  G4double a = theEvapLDPptr->LevelDensityParameter(ResidualA,
155                                                    ResidualZ,MaximalKineticEnergy+V-delta0);
156  G4double Ux = (2.5 + 150.0/G4double(ResidualA))*MeV;
157  G4double Ex = Ux + delta0;
158  G4double T  = 1.0/(std::sqrt(a/Ux) - 1.5/Ux);
159  //JMQ fixed bug in units
160  G4double E0 = Ex - T*(std::log(T/MeV) - std::log(a*MeV)/4.0 
161        - 1.25*std::log(Ux/MeV) + 2.0*std::sqrt(a*Ux));
162  //                      ***end RESIDUAL ***
163 
164  //                       ***PARENT***
165  //JMQ (September 2009) the following quantities refer to the PARENT:
166     
167  G4double deltaCN = fPairCorr->GetPairingCorrection(A, Z);                                   
168  G4double aCN     = theEvapLDPptr->LevelDensityParameter(A, Z, U-deltaCN);
169  G4double UxCN    = (2.5 + 150.0/G4double(A))*MeV;
170  G4double ExCN    = UxCN + deltaCN;
171  G4double TCN     = 1.0/(std::sqrt(aCN/UxCN) - 1.5/UxCN);
172  //                     ***end PARENT***
173
174  G4double Width;
175  G4double InitialLevelDensity;
176  G4double t = MaximalKineticEnergy/T;
177  if ( MaximalKineticEnergy < Ex ) {
178    //JMQ 190709 bug in I1 fixed (T was  missing)
179    Width = (I1(t,t)*T + (Beta+V)*I0(t))/std::exp(E0/T);
180    //JMQ 160909 fix:  InitialLevelDensity has been taken away
181    //(different conditions for initial CN..)
182  } else {
183
184    //VI minor speedup
185    G4double expE0T = std::exp(E0/T);
186    const G4double sqrt2 = std::sqrt(2.0);
187
188    G4double tx = Ex/T;
189    G4double s = 2.0*std::sqrt(a*(MaximalKineticEnergy-delta0));
190    G4double sx = 2.0*std::sqrt(a*(Ex-delta0));
191    Width = I1(t,tx)*T/expE0T + I3(s,sx)*std::exp(s)/(sqrt2*a);
192    // For charged particles (Beta+V) = 0 beacuse Beta = -V
193    if (theZ == 0) {
194      Width += (Beta+V)*(I0(tx)/expE0T + 2.0*sqrt2*I2(s,sx)*std::exp(s));
195    }
196  }
197 
198  //JMQ 14/07/2009 BIG BUG : NuclearMass is in MeV => hbarc instead of hbar_planck must be used
199  //    G4double g = (2.0*Spin+1.0)*NuclearMass/(pi2* hbar_Planck*hbar_Planck);
200  G4double g = (2.0*Spin+1.0)*NuclearMass/(pi2* hbarc*hbarc);
201 
202  //JMQ 190709 fix on Rb and  geometrical cross sections according to Furihata's paper
203  //                      (JAERI-Data/Code 2001-105, p6)
204  //    G4double RN = 0.0;
205  G4double Rb = 0.0;
206  if (theA > 4) 
207    {
208      //        G4double R1 = std::pow(ResidualA,1.0/3.0);
209      //        G4double R2 = std::pow(G4double(theA),1.0/3.0);
210      G4double Ad = fG4pow->Z13(ResidualA);
211      G4double Aj = fG4pow->Z13(theA);
212      //        RN = 1.12*(R1 + R2) - 0.86*((R1+R2)/(R1*R2));
213      Rb = 1.12*(Aj + Ad) - 0.86*((Aj+Ad)/(Aj*Ad))+2.85;
214      Rb *= fermi;
215    }
216  else if (theA>1)
217    {
218      G4double Ad = fG4pow->Z13(ResidualA);
219      G4double Aj = fG4pow->Z13(theA);
220      Rb=1.5*(Aj+Ad)*fermi;
221    }
222  else
223    {
224      G4double Ad = fG4pow->Z13(ResidualA);
225      Rb = 1.5*Ad*fermi;
226    }
227  //   G4double GeometricalXS = pi*RN*RN*std::pow(ResidualA,2./3.);
228  G4double GeometricalXS = pi*Rb*Rb; 
229  //end of JMQ fix on Rb by 190709
230 
231  //JMQ 160909 fix: initial level density must be calculated according to the
232  // conditions at the initial compound nucleus
233  // (it has been removed from previous "if" for the residual)
234
235  if ( U < ExCN ) 
236    {
237      //JMQ fixed bug in units
238      //VI moved the computation here
239      G4double E0CN = ExCN - TCN*(std::log(TCN/MeV) - std::log(aCN*MeV)/4.0 
240                                  - 1.25*std::log(UxCN/MeV) + 2.0*std::sqrt(aCN*UxCN));
241      InitialLevelDensity = (pi/12.0)*std::exp((U-E0CN)/TCN)/TCN;
242    } 
243  else 
244    {
245      //InitialLevelDensity = (pi/12.0)*std::exp(2*std::sqrt(aCN*(U-deltaCN)))/std::pow(aCN*std::pow(U-deltaCN,5.0),1.0/4.0);
246      //VI speedup
247      G4double x  = U-deltaCN;
248      G4double x1 = std::sqrt(aCN*x);
249      InitialLevelDensity = (pi/12.0)*std::exp(2*x1)/(x*std::sqrt(x1));
250    }
251
252  //JMQ 190709 BUG : pi instead of sqrt(pi) must be here according to Furihata's report:
253  //    Width *= std::sqrt(pi)*g*GeometricalXS*Alpha/(12.0*InitialLevelDensity);
254  Width *= pi*g*GeometricalXS*Alpha/(12.0*InitialLevelDensity); 
255   
256  return Width;
257}
258
259G4double G4GEMProbability::I3(G4double s, G4double sx)
260{
261  G4double s2 = s*s;
262  G4double sx2 = sx*sx;
263  G4double S = 1.0/std::sqrt(s);
264  G4double S2 = S*S;
265  G4double Sx = 1.0/std::sqrt(sx);
266  G4double Sx2 = Sx*Sx;
267 
268  G4double p1 = S *(2.0 + S2 *( 4.0 + S2 *( 13.5 + S2 *( 60.0 + S2 * 325.125 ))));
269  G4double p2 = Sx*Sx2 *(
270                         (s2-sx2) + Sx2 *(
271                                          (1.5*s2+0.5*sx2) + Sx2 *(
272                                                                   (3.75*s2+0.25*sx2) + Sx2 *(
273                                                                                              (12.875*s2+0.625*sx2) + Sx2 *(
274                                                                                                                            (59.0625*s2+0.9375*sx2) + Sx2 *(324.8*s2+3.28*sx2))))));
275 
276  p2 *= std::exp(sx-s);
277 
278  return p1-p2; 
279}
Note: See TracBrowser for help on using the repository browser.