source: trunk/source/processes/hadronic/cross_sections/src/G4TripathiLightCrossSection.cc @ 1315

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35//
36// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
37//
38// MODULE:              G4TripathiLightCrossSection.cc
39//
40// Version:             B.1
41// Date:                15/04/04
42// Author:              P R Truscott
43// Organisation:        QinetiQ Ltd, UK
44// Customer:            ESA/ESTEC, NOORDWIJK
45// Contract:            17191/03/NL/LvH
46//
47// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
48//
49// CHANGE HISTORY
50// --------------
51//
52// 6 October 2003, P R Truscott, QinetiQ Ltd, UK
53// Created.
54//
55// 15 March 2004, P R Truscott, QinetiQ Ltd, UK
56// Beta release
57//
58// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
59///////////////////////////////////////////////////////////////////////////////
60//
61#include "G4TripathiLightCrossSection.hh"
62#include "G4WilsonRadius.hh"
63#include "G4ParticleTable.hh"
64#include "G4IonTable.hh"
65
66///////////////////////////////////////////////////////////////////////////////
67//
68G4TripathiLightCrossSection::G4TripathiLightCrossSection ()
69{
70//
71//
72// Constructor only needs to instantiate the object which provides functions
73// to calculate the nuclear radius, and some other constants used to
74// calculate cross-sections.
75//
76  theWilsonRadius = new G4WilsonRadius();
77  r_0             = 1.1  * fermi;
78  third           = 1.0/3.0;
79//
80//
81// The following variable is set to true if
82// G4TripathiLightCrossSection::GetCrossSection is going to be called from
83// within G4TripathiLightCrossSection::GetCrossSection to check whether the
84// cross-section is behaviing anomalously in the low-energy region.
85//
86  lowEnergyCheck = false;
87}
88///////////////////////////////////////////////////////////////////////////////
89//
90G4TripathiLightCrossSection::~G4TripathiLightCrossSection ()
91{
92//
93//
94// Destructor just needs to delete the pointer to the G4WilsonRadius object.
95//
96  delete theWilsonRadius;
97}
98///////////////////////////////////////////////////////////////////////////////
99//
100G4bool G4TripathiLightCrossSection::IsApplicable
101  (const G4DynamicParticle* theProjectile, const G4Element* theTarget)
102{
103  return IsZAApplicable(theProjectile, theTarget->GetZ(), theTarget->GetN());
104}
105
106
107G4bool G4TripathiLightCrossSection::IsZAApplicable
108  (const G4DynamicParticle* theProjectile, G4double ZZ, G4double AA)
109{
110  G4bool result = false;
111  const G4double AT = AA;
112  const G4double ZT = ZZ;
113  const G4double ZP = theProjectile->GetDefinition()->GetPDGCharge();
114  const G4double AP = theProjectile->GetDefinition()->GetBaryonNumber();
115  if (theProjectile->GetKineticEnergy()/
116      theProjectile->GetDefinition()->GetBaryonNumber()<10.0*GeV &&
117     ((AT==1 && ZT==1) || (AP==1 && ZP==1) ||
118      (AT==1 && ZT==0) || (AP==1 && ZP==0) ||
119      (AT==2 && ZT==1) || (AP==2 && ZP==1) ||
120      (AT==3 && ZT==2) || (AP==3 && ZP==2) ||
121      (AT==4 && ZT==2) || (AP==4 && ZP==2))) result = true;
122  return result;
123}
124///////////////////////////////////////////////////////////////////////////////
125//
126G4double G4TripathiLightCrossSection::GetIsoZACrossSection
127  (const G4DynamicParticle* theProjectile, G4double ZZ, G4double AA,
128   G4double /*theTemperature*/)
129{
130//
131// Initialise the result.
132  G4double result = 0.0;
133//
134//
135// Get details of the projectile and target (nucleon number, atomic number,
136// kinetic enery and energy/nucleon.
137//
138  const G4double AT = AA;
139  const G4double ZT = ZZ;
140  const G4double EA = theProjectile->GetKineticEnergy()/MeV;
141  const G4double AP = theProjectile->GetDefinition()->GetBaryonNumber();
142  const G4double ZP = theProjectile->GetDefinition()->GetPDGCharge();
143        G4double E  = EA / AP;
144//
145//
146// Determine target mass and energy within the centre-of-mass frame.
147//
148  G4double mT = G4ParticleTable::GetParticleTable()
149                ->GetIonTable()
150                ->GetIonMass(static_cast<G4int>(ZT), static_cast<G4int>(AT));
151  G4LorentzVector pT(0.0, 0.0, 0.0, mT);
152  G4LorentzVector pP(theProjectile->Get4Momentum());
153  pT = pT + pP;
154  G4double E_cm = (pT.mag()-mT-pP.m())/MeV;
155//
156//
157// Determine nuclear radii.  Note that the r_p and r_T are defined differently
158// from Wilson et al.
159//
160  G4WilsonRadius theWilsonNuclearRadius;
161  G4double r_rms_p = theWilsonRadius->GetWilsonRMSRadius(AP);
162  G4double r_rms_t = theWilsonRadius->GetWilsonRMSRadius(AT);
163
164  G4double r_p = 1.29*r_rms_p;
165  G4double r_t = 1.29*r_rms_t;
166
167  G4double Radius = (r_p + r_t)/fermi + 1.2*(std::pow(AT, third) + std::pow(AP, third))/
168    std::pow(E_cm, third);
169
170  G4double B = 1.44 * ZP * ZT / Radius;
171//
172//
173// Now determine other parameters associated with the parametric
174// formula, depending upon the projectile and target.
175//
176  G4double T1 = 0.0;
177  G4double D  = 0.0;
178  G4double G  = 0.0;
179
180  if ((AT==1 && ZT==1) || (AP==1 && ZP==1))
181  {
182    T1 = 23.0;
183    D  = 1.85 + 0.16/(1+std::exp((500.0-E)/200.0));
184  }
185  else if ((AT==1 && ZT==0) || (AP==1 && ZP==0))
186  {
187    T1 = 18.0;
188    D  = 1.85 + 0.16/(1+std::exp((500.0-E)/200.0));
189  }
190  else if ((AT==2 && ZT==1) || (AP==2 && ZP==1))
191  {
192    T1 = 23.0;
193    D  = 1.65 + 0.1/(1+std::exp((500.0-E)/200.0));
194  }
195  else if ((AT==3 && ZT==2) || (AP==3 && ZP==2))
196  {
197    T1 = 40.0;
198    D  = 1.55;
199  }
200  else if (AP==4 && ZP==2)
201  {
202    if      (AT==4 && ZT==2) {T1 = 40.0; G = 300.0;}
203    else if (ZT==4)          {T1 = 25.0; G = 300.0;}
204    else if (ZT==7)          {T1 = 40.0; G = 500.0;}
205    else if (ZT==13)         {T1 = 25.0; G = 300.0;}
206    else if (ZT==26)         {T1 = 40.0; G = 300.0;}
207    else                     {T1 = 40.0; G = 75.0;}
208    D = 2.77 - 8.0E-3*AT + 1.8E-5*AT*AT-0.8/(1.0+std::exp((250.0-E)/G));
209  }
210  else if (AT==4 && ZT==2)
211  {
212    if      (AP==4 && ZP==2) {T1 = 40.0; G = 300.0;}
213    else if (ZP==4)          {T1 = 25.0; G = 300.0;}
214    else if (ZP==7)          {T1 = 40.0; G = 500.0;}
215    else if (ZP==13)         {T1 = 25.0; G = 300.0;}
216    else if (ZP==26)         {T1 = 40.0; G = 300.0;}
217    else                     {T1 = 40.0; G = 75.0;}
218    D = 2.77 - 8.0E-3*AP + 1.8E-5*AP*AP-0.8/(1.0+std::exp((250.0-E)/G));
219  }
220//
221//
222// C_E, S, deltaE, X1, S_L and X_m correspond directly with the original
223// formulae of Tripathi et al in his report.
224//
225  G4double C_E = D*(1.0-std::exp(-E/T1)) -
226                 0.292*std::exp(-E/792.0)*std::cos(0.229*std::pow(E,0.453));
227
228  G4double S = std::pow(AP,third)*std::pow(AT,third)/(std::pow(AP,third) + std::pow(AT,third));
229
230  G4double deltaE = 0.0;
231  G4double X1     = 0.0;
232  if (AT >= AP)
233  {
234    deltaE = 1.85*S + 0.16*S/std::pow(E_cm,third) - C_E + 0.91*(AT-2.0*ZT)*ZP/AT/AP;
235    X1     = 2.83 - 3.1E-2*AT + 1.7E-4*AT*AT;
236  }
237  else
238  {
239    deltaE = 1.85*S + 0.16*S/std::pow(E_cm,third) - C_E + 0.91*(AP-2.0*ZP)*ZT/AT/AP;
240    X1     = 2.83 - 3.1E-2*AP + 1.7E-4*AP*AP;
241  }
242  G4double S_L = 1.2 + 1.6*(1.0-std::exp(-E/15.0));
243  G4double X_m = 1.0 - X1*std::exp(-E/X1*S_L);
244//
245//
246// R_c is also highly dependent upon the A and Z of the projectile and
247// target.
248//
249  G4double R_c = 1.0;
250  if (AP==1 && ZP==1)
251  {
252    if      (AT==2 && ZT==1) R_c = 13.5;
253    else if (AT==3 && ZT==2) R_c = 21.0;
254    else if (AT==4 && ZT==2) R_c = 27.0;
255    else if (ZT==3)          R_c = 2.2;
256  }
257  else if (AT==1 && ZT==1)
258  {
259    if      (AP==2 && ZP==1) R_c = 13.5;
260    else if (AP==3 && ZP==2) R_c = 21.0;
261    else if (AP==4 && ZP==2) R_c = 27.0;
262    else if (ZP==3)          R_c = 2.2;
263  }
264  else if (AP==2 && ZP==1)
265  {
266    if       (AT==2 && ZT==1) R_c = 13.5;
267    else if (AT==4 && ZT==2)  R_c = 13.5;
268    else if (AT==12 && ZT==6) R_c = 6.0;
269  }
270  else if (AT==2 && ZT==1)
271  {
272    if       (AP==2 && ZP==1) R_c = 13.5;
273    else if (AP==4 && ZP==2)  R_c = 13.5;
274    else if (AP==12 && ZP==6) R_c = 6.0;
275  }
276  else if ((AP==4 && ZP==2 && (ZT==73 || ZT==79)) ||
277           (AT==4 && ZT==2 && (ZP==73 || ZP==79))) R_c = 0.6;
278//
279//
280// Find the total cross-section.  Check that it's value is positive, and if
281// the energy is less that 10 MeV/nuc, find out if the cross-section is
282// increasing with decreasing energy.  If so this is a sign that the function
283// is behaving badly at low energies, and the cross-section should be
284// set to zero.
285//
286  result = pi * r_0*r_0 *
287           std::pow((std::pow(AT,third) + std::pow(AP,third) + deltaE),2.0) *
288           (1.0 - R_c*B/E_cm) * X_m;
289  if (!lowEnergyCheck)
290  {
291    if (result < 0.0)
292      result = 0.0;
293    else if (E < 6.0*MeV)
294    {
295      G4double f  = 0.95;
296      G4DynamicParticle slowerProjectile = *theProjectile;
297      slowerProjectile.SetKineticEnergy(f * EA * MeV);
298      // G4TripathiLightCrossSection theTripathiLightCrossSection; // MHM 20090824 Not needed
299          // theTripathiLightCrossSection.SetLowEnergyCheck(true);
300          G4bool savelowenergy=lowEnergyCheck;
301          SetLowEnergyCheck(true);
302      G4double resultp =
303        GetIsoZACrossSection(&slowerProjectile, ZZ, AA, 0.0);
304          SetLowEnergyCheck(savelowenergy);
305      if (resultp >result) result = 0.0;
306    }
307  }
308
309  return result;
310}
311
312
313G4double G4TripathiLightCrossSection::GetCrossSection
314  (const G4DynamicParticle* theProjectile, const G4Element* theTarget,
315  G4double theTemperature)
316{
317  G4int nIso = theTarget->GetNumberOfIsotopes();
318  G4double xsection = 0;
319     
320  if (nIso) {
321    G4double sig;
322    G4IsotopeVector* isoVector = theTarget->GetIsotopeVector();
323    G4double* abundVector = theTarget->GetRelativeAbundanceVector();
324    G4double ZZ;
325    G4double AA;
326     
327    for (G4int i = 0; i < nIso; i++) {
328      ZZ = G4double( (*isoVector)[i]->GetZ() );
329      AA = G4double( (*isoVector)[i]->GetN() );
330      sig = GetIsoZACrossSection(theProjectile, ZZ, AA, theTemperature);
331      xsection += sig*abundVector[i];
332    }
333   
334  } else {
335    xsection =
336      GetIsoZACrossSection(theProjectile, theTarget->GetZ(), theTarget->GetN(),
337                           theTemperature);
338  }
339   
340  return xsection;
341}
342
343
344///////////////////////////////////////////////////////////////////////////////
345//
346void G4TripathiLightCrossSection::SetLowEnergyCheck (G4bool aLowEnergyCheck)
347{
348  lowEnergyCheck = aLowEnergyCheck;
349}
350///////////////////////////////////////////////////////////////////////////////
351//
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