Geant4  10.00.p01
G4GEMProbability.cc
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26 // $Id: G4GEMProbability.cc 74869 2013-10-23 09:26:17Z gcosmo $
27 //
28 //---------------------------------------------------------------------
29 //
30 // Geant4 class G4GEMProbability
31 //
32 //
33 // Hadronic Process: Nuclear De-excitations
34 // by V. Lara (Sept 2001)
35 //
36 //
37 // Hadronic Process: Nuclear De-excitations
38 // by V. Lara (Sept 2001)
39 //
40 // J. M. Quesada : several fixes in total GEM width
41 // J. M. Quesada 14/07/2009 bug fixed in total emission width (hbarc)
42 // J. M. Quesada (September 2009) several fixes:
43 // -level density parameter of residual calculated at its right excitation energy.
44 // -InitialLeveldensity calculated according to the right conditions of the
45 // initial excited nucleus.
46 // J. M. Quesada 19/04/2010 fix in emission probability calculation.
47 // V.Ivanchenko 20/04/2010 added usage of G4Pow and use more safe computation
48 // V.Ivanchenko 18/05/2010 trying to speedup the most slow method
49 // by usage of G4Pow, integer Z and A; moved constructor,
50 // destructor and virtual functions to source
51 
52 #include "G4GEMProbability.hh"
53 #include "G4PairingCorrection.hh"
54 #include "G4PhysicalConstants.hh"
55 #include "G4SystemOfUnits.hh"
56 #include "G4Log.hh"
57 #include "G4Exp.hh"
58 
60  theA(anA), theZ(aZ), Spin(aSpin), theCoulombBarrierPtr(0),
61  Normalization(1.0)
62 {
65  fPlanck= CLHEP::hbar_Planck*fG4pow->logZ(2);
67 }
68 
70 {
71  delete theEvapLDPptr;
72 }
73 
75  G4double MaximalKineticEnergy)
76 {
77  G4double probability = 0.0;
78 
79  if (MaximalKineticEnergy > 0.0 && fragment.GetExcitationEnergy() > 0.0) {
80  G4double CoulombBarrier = GetCoulombBarrier(fragment);
81 
82  probability =
83  CalcProbability(fragment,MaximalKineticEnergy,CoulombBarrier);
84 
85  // Next there is a loop over excited states for this channel
86  // summing probabilities
87  size_t nn = ExcitEnergies.size();
88  if (0 < nn) {
89  G4double SavedSpin = Spin;
90  for (size_t i = 0; i <nn; ++i) {
91  Spin = ExcitSpins[i];
92  // substract excitation energies
93  G4double Tmax = MaximalKineticEnergy - ExcitEnergies[i];
94  if (Tmax > 0.0) {
95  G4double width = CalcProbability(fragment,Tmax,CoulombBarrier);
96  //JMQ April 2010 added condition to prevent reported crash
97  // update probability
98  if (width > 0. && fPlanck < width*ExcitLifetimes[i]) {
99  probability += width;
100  }
101  }
102  }
103  // Restore Spin
104  Spin = SavedSpin;
105  }
106  }
107  Normalization = probability;
108  return probability;
109 }
110 
111 
113  G4double MaximalKineticEnergy,
114  G4double V)
115 
116 // Calculate integrated probability (width) for evaporation channel
117 {
118  G4int A = fragment.GetA_asInt();
119  G4int Z = fragment.GetZ_asInt();
120 
121  G4int ResidualA = A - theA;
122  G4int ResidualZ = Z - theZ;
123  G4double U = fragment.GetExcitationEnergy();
124 
125  G4double NuclearMass = fragment.ComputeGroundStateMass(theZ, theA);
126 
127  G4double Alpha = CalcAlphaParam(fragment);
128  G4double Beta = CalcBetaParam(fragment);
129 
130  // ***RESIDUAL***
131  //JMQ (September 2009) the following quantities refer to the RESIDUAL:
132 
133  G4double delta0 = fPairCorr->GetPairingCorrection(ResidualA, ResidualZ);
134 
136  LevelDensityParameter(ResidualA,ResidualZ,MaximalKineticEnergy+V-delta0);
137  G4double Ux = (2.5 + 150.0/G4double(ResidualA))*MeV;
138  G4double Ex = Ux + delta0;
139  G4double T = 1.0/(std::sqrt(a/Ux) - 1.5/Ux);
140  //JMQ fixed bug in units
141  G4double E0 = Ex - T*(G4Log(T/MeV) - G4Log(a*MeV)/4.0
142  - 1.25*G4Log(Ux/MeV) + 2.0*std::sqrt(a*Ux));
143  // ***end RESIDUAL ***
144 
145  // ***PARENT***
146  //JMQ (September 2009) the following quantities refer to the PARENT:
147 
148  G4double deltaCN = fPairCorr->GetPairingCorrection(A, Z);
149  G4double aCN = theEvapLDPptr->LevelDensityParameter(A, Z, U-deltaCN);
150  G4double UxCN = (2.5 + 150.0/G4double(A))*MeV;
151  G4double ExCN = UxCN + deltaCN;
152  G4double TCN = 1.0/(std::sqrt(aCN/UxCN) - 1.5/UxCN);
153  // ***end PARENT***
154 
155  G4double Width;
156  G4double InitialLevelDensity;
157  G4double t = MaximalKineticEnergy/T;
158  if ( MaximalKineticEnergy < Ex ) {
159  //JMQ 190709 bug in I1 fixed (T was missing)
160  Width = (I1(t,t)*T + (Beta+V)*I0(t))/G4Exp(E0/T);
161  //JMQ 160909 fix: InitialLevelDensity has been taken away
162  //(different conditions for initial CN..)
163  } else {
164 
165  //VI minor speedup
166  G4double expE0T = G4Exp(E0/T);
167  static const G4double sqrt2 = std::sqrt(2.0);
168 
169  G4double tx = Ex/T;
170  G4double s0 = 2.0*std::sqrt(a*(MaximalKineticEnergy-delta0));
171  G4double sx = 2.0*std::sqrt(a*(Ex-delta0));
172  Width = I1(t,tx)*T/expE0T + I3(s0,sx)*G4Exp(s0)/(sqrt2*a);
173  // For charged particles (Beta+V) = 0 beacuse Beta = -V
174  if (theZ == 0) {
175  Width += (Beta+V)*(I0(tx)/expE0T + 2.0*sqrt2*I2(s0,sx)*G4Exp(s0));
176  }
177  }
178 
179  //JMQ 14/07/2009 BIG BUG : NuclearMass is in MeV => hbarc instead of hbar_planck must be used
180  // G4double g = (2.0*Spin+1.0)*NuclearMass/(pi2* hbar_Planck*hbar_Planck);
181  G4double gg = (2.0*Spin+1.0)*NuclearMass/(pi2* hbarc*hbarc);
182 
183  //JMQ 190709 fix on Rb and geometrical cross sections according to Furihata's paper
184  // (JAERI-Data/Code 2001-105, p6)
185  // G4double RN = 0.0;
186  G4double Rb = 0.0;
187  if (theA > 4)
188  {
189  G4double Ad = fG4pow->Z13(ResidualA);
190  G4double Aj = fG4pow->Z13(theA);
191  Rb = 1.12*(Aj + Ad) - 0.86*((Aj+Ad)/(Aj*Ad))+2.85;
192  Rb *= fermi;
193  }
194  else if (theA>1)
195  {
196  G4double Ad = fG4pow->Z13(ResidualA);
197  G4double Aj = fG4pow->Z13(theA);
198  Rb=1.5*(Aj+Ad)*fermi;
199  }
200  else
201  {
202  G4double Ad = fG4pow->Z13(ResidualA);
203  Rb = 1.5*Ad*fermi;
204  }
205  // G4double GeometricalXS = pi*RN*RN*std::pow(ResidualA,2./3.);
206  G4double GeometricalXS = pi*Rb*Rb;
207  //end of JMQ fix on Rb by 190709
208 
209  //JMQ 160909 fix: initial level density must be calculated according to the
210  // conditions at the initial compound nucleus
211  // (it has been removed from previous "if" for the residual)
212 
213  if ( U < ExCN )
214  {
215  //JMQ fixed bug in units
216  //VI moved the computation here
217  G4double E0CN = ExCN - TCN*(G4Log(TCN/MeV) - G4Log(aCN*MeV)/4.0
218  - 1.25*G4Log(UxCN/MeV)
219  + 2.0*std::sqrt(aCN*UxCN));
220  InitialLevelDensity = (pi/12.0)*G4Exp((U-E0CN)/TCN)/TCN;
221  }
222  else
223  {
224  //VI speedup
225  G4double x = U-deltaCN;
226  G4double x1 = std::sqrt(aCN*x);
227  InitialLevelDensity = (pi/12.0)*G4Exp(2*x1)/(x*std::sqrt(x1));
228  }
229 
230  //JMQ 190709 BUG : pi instead of sqrt(pi) must be here according
231  // to Furihata's report:
232  Width *= pi*gg*GeometricalXS*Alpha/(12.0*InitialLevelDensity);
233 
234  return Width;
235 }
236 
238 {
239  G4double s2 = s0*s0;
240  G4double sx2 = sx*sx;
241  G4double S = 1.0/std::sqrt(s0);
242  G4double S2 = S*S;
243  G4double Sx = 1.0/std::sqrt(sx);
244  G4double Sx2 = Sx*Sx;
245 
246  G4double p1 = S *(2.0 + S2 *( 4.0 + S2 *( 13.5 + S2 *( 60.0 + S2 * 325.125 ))));
247  G4double p2 = Sx*Sx2 *(
248  (s2-sx2) + Sx2 *(
249  (1.5*s2+0.5*sx2) + Sx2 *(
250  (3.75*s2+0.25*sx2) + Sx2 *(
251  (12.875*s2+0.625*sx2) + Sx2 *(
252  (59.0625*s2+0.9375*sx2) + Sx2 *(324.8*s2+3.28*sx2))))));
253 
254  p2 *= G4Exp(sx-s0);
255 
256  return p1-p2;
257 }
G4double I3(G4double s0, G4double sx)
static G4Pow * GetInstance()
Definition: G4Pow.cc:53
static const double MeV
Definition: G4SIunits.hh:193
G4double I1(G4double t, G4double tx)
G4double EmissionProbability(const G4Fragment &fragment, G4double anEnergy)
const G4double pi
G4double CalcAlphaParam(const G4Fragment &) const
G4PairingCorrection * fPairCorr
G4double GetCoulombBarrier(const G4Fragment &fragment) const
#define width
G4double CalcProbability(const G4Fragment &fragment, G4double MaximalKineticEnergy, G4double V)
G4double a
Definition: TRTMaterials.hh:39
std::vector< G4double > ExcitLifetimes
int G4int
Definition: G4Types.hh:78
G4double I2(G4double s0, G4double sx)
G4double logZ(G4int Z) const
Definition: G4Pow.hh:165
G4double Z13(G4int Z) const
Definition: G4Pow.hh:129
std::vector< G4double > ExcitSpins
G4int GetA_asInt() const
Definition: G4Fragment.hh:238
G4double GetPairingCorrection(G4int A, G4int Z) const
G4VLevelDensityParameter * theEvapLDPptr
virtual ~G4GEMProbability()
G4double CalcBetaParam(const G4Fragment &) const
std::vector< G4double > ExcitEnergies
static const G4double A[nN]
G4double G4Log(G4double x)
Definition: G4Log.hh:227
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition: G4Exp.hh:180
static G4PairingCorrection * GetInstance()
virtual G4double LevelDensityParameter(G4int A, G4int Z, G4double U) const =0
G4int GetZ_asInt() const
Definition: G4Fragment.hh:243
G4double I0(G4double t)
double G4double
Definition: G4Types.hh:76
G4double ComputeGroundStateMass(G4int Z, G4int A) const
Definition: G4Fragment.hh:293
static const double fermi
Definition: G4SIunits.hh:93
G4double GetExcitationEnergy() const
Definition: G4Fragment.hh:255