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 | // |
---|
27 | // The lust update: M.V. Kossov, CERN/ITEP(Moscow) 17-June-02 |
---|
28 | // GEANT4 tag $Name: geant4-09-02-ref-02 $ |
---|
29 | // |
---|
30 | // |
---|
31 | // G4 Physics class: G4QNeutronNuclearCrossSection for gamma+A cross sections |
---|
32 | // @@ A preliminary temporary class identical to G4QProtonNuclearCS. Must be improved. @@ |
---|
33 | // Created: M.V. Kossov, CERN/ITEP(Moscow), 20-Dec-03 |
---|
34 | // The last update: M.V. Kossov, CERN/ITEP (Moscow) 15-Feb-04 |
---|
35 | // -------------------------------------------------------------------------------- |
---|
36 | // **************************************************************************************** |
---|
37 | // ****** This CLASS is a property of the CHIPS hadronic package in Geant4 (M. Kosov) ***** |
---|
38 | // *********** DO NOT MAKE ANY CHANGE without approval of Mikhail.Kossov@cern.ch ********** |
---|
39 | // **************************************************************************************** |
---|
40 | // |
---|
41 | //#define debug |
---|
42 | //#define pdebug |
---|
43 | //#define debug3 |
---|
44 | //#define debugn |
---|
45 | //#define debugs |
---|
46 | |
---|
47 | #include "G4QNeutronNuclearCrossSection.hh" |
---|
48 | |
---|
49 | // Initialization of the |
---|
50 | G4double* G4QNeutronNuclearCrossSection::lastLEN=0; // Pointer to the lastArray of LowEn CS |
---|
51 | G4double* G4QNeutronNuclearCrossSection::lastHEN=0; // Pointer to the lastArray of HighEn CS |
---|
52 | G4int G4QNeutronNuclearCrossSection::lastN=0; // The last N of calculated nucleus |
---|
53 | G4int G4QNeutronNuclearCrossSection::lastZ=0; // The last Z of calculated nucleus |
---|
54 | G4double G4QNeutronNuclearCrossSection::lastP=0.; // Last used in cross section Momentum |
---|
55 | G4double G4QNeutronNuclearCrossSection::lastTH=0.; // Last threshold momentum |
---|
56 | G4double G4QNeutronNuclearCrossSection::lastCS=0.; // Last value of the Cross Section |
---|
57 | G4int G4QNeutronNuclearCrossSection::lastI=0; // The last position in the DAMDB |
---|
58 | |
---|
59 | // Returns Pointer to the G4VQCrossSection class |
---|
60 | G4VQCrossSection* G4QNeutronNuclearCrossSection::GetPointer() |
---|
61 | { |
---|
62 | static G4QNeutronNuclearCrossSection theCrossSection; //**Static body of Cross Section** |
---|
63 | return &theCrossSection; |
---|
64 | } |
---|
65 | |
---|
66 | // The main member function giving the collision cross section (P is in IU, CS is in mb) |
---|
67 | // Make pMom in independent units ! (Now it is MeV) |
---|
68 | G4double G4QNeutronNuclearCrossSection::GetCrossSection(G4bool fCS, G4double pMom, |
---|
69 | G4int tgZ, G4int tgN, G4int) |
---|
70 | { |
---|
71 | static G4int j; // A#0f records found in DB for this projectile |
---|
72 | static std::vector <G4int> colN; // Vector of N for calculated nuclei (isotops) |
---|
73 | static std::vector <G4int> colZ; // Vector of Z for calculated nuclei (isotops) |
---|
74 | static std::vector <G4double> colP; // Vector of last momenta for the reaction |
---|
75 | static std::vector <G4double> colTH; // Vector of energy thresholds for the reaction |
---|
76 | static std::vector <G4double> colCS; // Vector of last cross sections for the reaction |
---|
77 | // ***---*** End of the mandatory Static Definitions of the Associative Memory ***---*** |
---|
78 | G4double pEn=pMom; |
---|
79 | #ifdef pdebug |
---|
80 | G4cout<<"G4QNtCS::GetCS:>>> f="<<fCS<<", p="<<pMom<<", Z="<<tgZ<<"("<<lastZ<<") ,N="<<tgN |
---|
81 | <<"("<<lastN<<"),PDG=2212, P="<<pEn<<"("<<lastTH<<")"<<",Sz="<<colN.size()<<G4endl; |
---|
82 | #endif |
---|
83 | G4bool in=false; // By default the isotope must be found in the AMDB |
---|
84 | if(tgN!=lastN || tgZ!=lastZ) // The nucleus was not the last used isotope |
---|
85 | { |
---|
86 | in = false; // By default the isotope haven't be found in AMDB |
---|
87 | lastP = 0.; // New momentum history (nothing to compare with) |
---|
88 | lastN = tgN; // The last N of the calculated nucleus |
---|
89 | lastZ = tgZ; // The last Z of the calculated nucleus |
---|
90 | lastI = colN.size(); // Size of the Associative Memory DB in the heap |
---|
91 | j = 0; // A#0f records found in DB for this projectile |
---|
92 | if(lastI) for(G4int i=0; i<lastI; i++) // The partType is found |
---|
93 | { // The nucleus with is found in AMDB |
---|
94 | if(colN[i]==tgN && colZ[i]==tgZ) |
---|
95 | { |
---|
96 | lastI=i; |
---|
97 | lastTH =colTH[i]; // Last THreshold (A-dependent) |
---|
98 | #ifdef pdebug |
---|
99 | G4cout<<"G4QNtCS::GetCS:*Found* P="<<pMom<<",Threshold="<<lastTH<<",j="<<j<<G4endl; |
---|
100 | #endif |
---|
101 | if(pEn<=lastTH) |
---|
102 | { |
---|
103 | #ifdef pdebug |
---|
104 | G4cout<<"G4QNtCS::GetCS:Found T="<<pEn<<" < Threshold="<<lastTH<<",CS=0"<<G4endl; |
---|
105 | #endif |
---|
106 | return 0.; // Energy is below the Threshold value |
---|
107 | } |
---|
108 | lastP =colP [i]; // Last Momentum (A-dependent) |
---|
109 | lastCS =colCS[i]; // Last CrossSect (A-dependent) |
---|
110 | // if(std::fabs(lastP/pMom-1.)<tolerance) |
---|
111 | if(lastP==pMom) // VI do not use tolerance |
---|
112 | { |
---|
113 | #ifdef pdebug |
---|
114 | G4cout<<"G4QNeutronNuclCS::GetCS:P="<<pMom<<",CS="<<lastCS*millibarn<<G4endl; |
---|
115 | #endif |
---|
116 | CalculateCrossSection(fCS,-1,j,2212,lastZ,lastN,pMom); // Update param's only |
---|
117 | return lastCS*millibarn; // Use theLastCS |
---|
118 | } |
---|
119 | in = true; // This is the case when the isotop is found in DB |
---|
120 | // Momentum pMom is in IU ! @@ Units |
---|
121 | #ifdef pdebug |
---|
122 | G4cout<<"G4QNtCS::G:UpdatDB P="<<pMom<<",f="<<fCS<<",lI="<<lastI<<",j="<<j<<G4endl; |
---|
123 | #endif |
---|
124 | lastCS=CalculateCrossSection(fCS,-1,j,2212,lastZ,lastN,pMom); // read & update |
---|
125 | #ifdef pdebug |
---|
126 | G4cout<<"G4QNeutronCS::GetCrosSec:*****>New (inDB) Calculated CS="<<lastCS<<G4endl; |
---|
127 | #endif |
---|
128 | if(lastCS<=0. && pEn>lastTH) // Correct the threshold |
---|
129 | { |
---|
130 | #ifdef pdebug |
---|
131 | G4cout<<"G4QNtCS::GetCS: New T="<<pEn<<"(CS=0) > Threshold="<<lastTH<<G4endl; |
---|
132 | #endif |
---|
133 | lastTH=pEn; |
---|
134 | } |
---|
135 | break; // Go out of the LOOP |
---|
136 | } |
---|
137 | #ifdef pdebug |
---|
138 | G4cout<<"-->G4QNeutronNuclearCrossSec::GetCrosSec: pPDG=2212, j="<<j<<", N="<<colN[i] |
---|
139 | <<",Z["<<i<<"]="<<colZ[i]<<G4endl; |
---|
140 | #endif |
---|
141 | j++; // Increment a#0f records found in DB |
---|
142 | } |
---|
143 | if(!in) // This nucleus has not been calculated previously |
---|
144 | { |
---|
145 | #ifdef pdebug |
---|
146 | G4cout<<"G4QNtCS::GetCrosSec:CalcNew P="<<pMom<<",f="<<fCS<<",lastI="<<lastI<<G4endl; |
---|
147 | #endif |
---|
148 | //!!The slave functions must provide cross-sections in millibarns (mb) !! (not in IU) |
---|
149 | lastCS=CalculateCrossSection(fCS,0,j,2212,lastZ,lastN,pMom); //calculate & create |
---|
150 | if(lastCS<=0.) |
---|
151 | { |
---|
152 | lastTH = ThresholdEnergy(tgZ, tgN); // The Threshold Energy which is now the last |
---|
153 | #ifdef pdebug |
---|
154 | G4cout<<"G4QNeutronNuclCSec::GetCrossSect: NewThresh="<<lastTH<<",T="<<pEn<<G4endl; |
---|
155 | #endif |
---|
156 | if(pEn>lastTH) |
---|
157 | { |
---|
158 | #ifdef pdebug |
---|
159 | G4cout<<"G4QNeutCS::GetCS: First T="<<pEn<<"(CS=0) > Threshold="<<lastTH<<G4endl; |
---|
160 | #endif |
---|
161 | lastTH=pEn; |
---|
162 | } |
---|
163 | } |
---|
164 | #ifdef pdebug |
---|
165 | G4cout<<"G4QNtCS::GetCrosSec: New CS="<<lastCS<<",lZ="<<lastN<<",lN="<<lastZ<<G4endl; |
---|
166 | #endif |
---|
167 | colN.push_back(tgN); |
---|
168 | colZ.push_back(tgZ); |
---|
169 | colP.push_back(pMom); |
---|
170 | colTH.push_back(lastTH); |
---|
171 | colCS.push_back(lastCS); |
---|
172 | #ifdef pdebug |
---|
173 | G4cout<<"G4QNtCS::GetCS:1st,P="<<pMom<<"(MeV),CS="<<lastCS*millibarn<<"(mb)"<<G4endl; |
---|
174 | #endif |
---|
175 | return lastCS*millibarn; |
---|
176 | } // End of creation of the new set of parameters |
---|
177 | else |
---|
178 | { |
---|
179 | #ifdef pdebug |
---|
180 | G4cout<<"G4QNeutronNuclearCrossSect::GetCS: Update lastI="<<lastI<<",j="<<j<<G4endl; |
---|
181 | #endif |
---|
182 | colP[lastI]=pMom; |
---|
183 | colCS[lastI]=lastCS; |
---|
184 | } |
---|
185 | } // End of parameters udate |
---|
186 | else if(pEn<=lastTH) |
---|
187 | { |
---|
188 | #ifdef pdebug |
---|
189 | G4cout<<"G4QNeutCS::GetCS: Current T="<<pEn<<" < Threshold="<<lastTH<<", CS=0"<<G4endl; |
---|
190 | #endif |
---|
191 | return 0.; // Momentum is below the Threshold Value -> CS=0 |
---|
192 | } |
---|
193 | // else if(std::fabs(lastP/pMom-1.)<tolerance) |
---|
194 | else if(lastP==pMom) // do not use tolerance |
---|
195 | { |
---|
196 | #ifdef pdebug |
---|
197 | G4cout<<"G4QNtCS::GetCS:OldCur P="<<pMom<<"="<<pMom<<", CS="<<lastCS*millibarn<<G4endl; |
---|
198 | #endif |
---|
199 | return lastCS*millibarn; // Use theLastCS |
---|
200 | } |
---|
201 | else |
---|
202 | { |
---|
203 | #ifdef pdebug |
---|
204 | G4cout<<"G4QNtCS::GetCS:UpdatCur P="<<pMom<<",f="<<fCS<<",I="<<lastI<<",j="<<j<<G4endl; |
---|
205 | #endif |
---|
206 | lastCS=CalculateCrossSection(fCS,1,j,2212,lastZ,lastN,pMom); // Only UpdateDB |
---|
207 | lastP=pMom; |
---|
208 | } |
---|
209 | #ifdef pdebug |
---|
210 | G4cout<<"G4QNtCS::GetCroSec:End,P="<<pMom<<"(MeV),CS="<<lastCS*millibarn<<"(mb)"<<G4endl; |
---|
211 | #endif |
---|
212 | return lastCS*millibarn; |
---|
213 | } |
---|
214 | |
---|
215 | // The main member function giving the gamma-A cross section (E in GeV, CS in mb) |
---|
216 | G4double G4QNeutronNuclearCrossSection::CalculateCrossSection(G4bool, G4int F, G4int I, |
---|
217 | G4int, G4int targZ, G4int targN, G4double Momentum) |
---|
218 | { |
---|
219 | static const G4double THmin=27.; // minimum Momentum (MeV/c) Threshold |
---|
220 | static const G4double THmiG=THmin*.001; // minimum Momentum (GeV/c) Threshold |
---|
221 | static const G4double dP=10.; // step for the LEN (Low ENergy) table MeV/c |
---|
222 | static const G4double dPG=dP*.001; // step for the LEN (Low ENergy) table GeV/c |
---|
223 | static const G4int nL=105; // A#of LEN points in E (step 10 MeV/c) |
---|
224 | static const G4double Pmin=THmin+(nL-1)*dP; // minP for the HighE part with safety |
---|
225 | static const G4double Pmax=227000.; // maxP for the HEN (High ENergy) part 227 GeV |
---|
226 | static const G4int nH=224; // A#of HEN points in lnE |
---|
227 | static const G4double milP=std::log(Pmin);// Low logarithm energy for the HEN part |
---|
228 | static const G4double malP=std::log(Pmax);// High logarithm energy (each 2.75 percent) |
---|
229 | static const G4double dlP=(malP-milP)/(nH-1); // Step in log energy in the HEN part |
---|
230 | static const G4double milPG=std::log(.001*Pmin);// Low logarithm energy for the HEN part GeV/c |
---|
231 | // |
---|
232 | // Associative memory for acceleration |
---|
233 | //static std::vector <G4double> spA; // shadowing coefficients (A-dependent) |
---|
234 | static std::vector <G4double*> LEN; // Vector of pointers to LowEnProtonCrossSection |
---|
235 | static std::vector <G4double*> HEN; // Vector of pointers to HighEnProtonCrossSection |
---|
236 | #ifdef debug |
---|
237 | G4cout<<"G4QNeutronNuclearCS::CalcCS: N="<<targN<<",Z="<<targZ<<",P="<<Momentum<<G4endl; |
---|
238 | #endif |
---|
239 | if (Momentum<THmin) return 0.; // @@ This can be dangerouse for the heaviest nuc.! |
---|
240 | G4double sigma=0.; |
---|
241 | if(F&&I) sigma=0.; // @@ *!* Fake line *!* to use F & I !!!Temporary!!! |
---|
242 | G4double A=targN+targZ; // A of the target |
---|
243 | if(F<=0) // This isotope was not the last used isotop |
---|
244 | { |
---|
245 | if(F<0) // This isotope was found in DAMDB =========> RETRIEVE |
---|
246 | { |
---|
247 | lastLEN=LEN[I]; // Pointer to prepared LowEnergy cross sections |
---|
248 | lastHEN=HEN[I]; // Pointer to prepared High Energy cross sections |
---|
249 | } |
---|
250 | else // This isotope wasn't calculated previously => CREATE |
---|
251 | { |
---|
252 | lastLEN = new G4double[nL]; // Allocate memory for the new LEN cross sections |
---|
253 | lastHEN = new G4double[nH]; // Allocate memory for the new HEN cross sections |
---|
254 | // --- Instead of making a separate function --- |
---|
255 | G4double P=THmiG; // Table threshold in GeV/c |
---|
256 | for(G4int m=0; m<nL; m++) |
---|
257 | { |
---|
258 | lastLEN[m] = CrossSectionLin(targZ, targN, P); |
---|
259 | P+=dPG; |
---|
260 | } |
---|
261 | G4double lP=milPG; |
---|
262 | for(G4int n=0; n<nH; n++) |
---|
263 | { |
---|
264 | lastHEN[n] = CrossSectionLog(targZ, targN, lP); |
---|
265 | lP+=dlP; |
---|
266 | } |
---|
267 | // --- End of possible separate function |
---|
268 | // *** The synchronization check *** |
---|
269 | G4int sync=LEN.size(); |
---|
270 | if(sync!=I) G4cerr<<"***G4QNeutronNuclCS::CalcCrossSect:Sync="<<sync<<"#"<<I<<G4endl; |
---|
271 | LEN.push_back(lastLEN); // added LEN, found by AH 10/7/02 |
---|
272 | HEN.push_back(lastHEN); // added HEN, found by AH 10/7/02 |
---|
273 | } // End of creation of the new set of parameters |
---|
274 | } // End of parameters udate |
---|
275 | // ============================== NOW the Magic Formula ================================= |
---|
276 | if (Momentum<lastTH) return 0.; // It must be already checked in the interface class |
---|
277 | else if (Momentum<Pmin) // High Energy region |
---|
278 | { |
---|
279 | #ifdef debug |
---|
280 | G4cout<<"G4QNeutCS::CalcCS:bLEN A="<<A<<", nL="<<nL<<",TH="<<THmin<<",dP="<<dP<<G4endl; |
---|
281 | #endif |
---|
282 | if(A<=1.) sigma=0.; |
---|
283 | else sigma=EquLinearFit(Momentum,nL,THmin,dP,lastLEN); |
---|
284 | #ifdef debugn |
---|
285 | if(sigma<0.) |
---|
286 | G4cout<<"G4QNeutCS::CalcCS:A="<<A<<",E="<<Momentum<<",T="<<THmin<<",dP="<<dP<<G4endl; |
---|
287 | #endif |
---|
288 | } |
---|
289 | else if (Momentum<Pmax) // High Energy region |
---|
290 | { |
---|
291 | G4double lP=std::log(Momentum); |
---|
292 | #ifdef debug |
---|
293 | G4cout<<"G4QNeutNucCS::CalcCS: before HEN nH="<<nH<<",iE="<<milP<<",dlP="<<dlP<<G4endl; |
---|
294 | #endif |
---|
295 | sigma=EquLinearFit(lP,nH,milP,dlP,lastHEN); |
---|
296 | } |
---|
297 | else // UHE region (calculation, not frequent) |
---|
298 | { |
---|
299 | G4double P=0.001*Momentum; // Approximation formula is for P in GeV/c |
---|
300 | sigma=CrossSectionFormula(targZ, targN, P, std::log(P)); |
---|
301 | } |
---|
302 | #ifdef debug |
---|
303 | G4cout<<"G4QNeutronNuclearCrossSection::CalcCS: sigma="<<sigma<<G4endl; |
---|
304 | #endif |
---|
305 | if(sigma<0.) return 0.; |
---|
306 | return sigma; |
---|
307 | } |
---|
308 | |
---|
309 | // Electromagnetic momentum-threshold (in MeV/c) |
---|
310 | G4double G4QNeutronNuclearCrossSection::ThresholdMomentum(G4int tZ, G4int tN) |
---|
311 | { |
---|
312 | static const G4double third=1./3.; |
---|
313 | static const G4double pM = G4QPDGCode(2212).GetMass(); // Proton mass in MeV |
---|
314 | static const G4double tpM= pM+pM; // Doubled proton mass (MeV) |
---|
315 | G4double tA=tZ+tN; |
---|
316 | if(tZ<.99 || tN<0.) return 0.; |
---|
317 | //G4double dE=1.263*tZ/(1.+std::pow(tA,third)); |
---|
318 | G4double dE=tZ/(1.+std::pow(tA,third)); // Safety for diffused edge of the nucleus (QE) |
---|
319 | return std::sqrt(dE*(tpM+dE)); |
---|
320 | } |
---|
321 | |
---|
322 | // Calculation formula for proton-nuclear inelastic cross-section (mb) (P in GeV/c) |
---|
323 | G4double G4QNeutronNuclearCrossSection::CrossSectionLin(G4int tZ, G4int tN, G4double P) |
---|
324 | { |
---|
325 | G4double sigma=0.; |
---|
326 | if(P<ThresholdMomentum(tZ,tN)*.001) return sigma; |
---|
327 | G4double lP=std::log(P); |
---|
328 | if(tZ==1&&!tN){if(P>.35) sigma=CrossSectionFormula(tZ,tN,P,lP);}// s(pp)=0 below 350Mev/c |
---|
329 | else if(tZ<93 && tN<239) // General solution |
---|
330 | { |
---|
331 | G4double pex=0.; |
---|
332 | G4double pos=0.; |
---|
333 | G4double wid=1.; |
---|
334 | if(tZ==13 && tN==14) // Excited metastable states |
---|
335 | { |
---|
336 | pex=230.; |
---|
337 | pos=.13; |
---|
338 | wid=8.e-5; |
---|
339 | } |
---|
340 | else if(tZ<7) |
---|
341 | { |
---|
342 | if(tZ==6 && tN==6) |
---|
343 | { |
---|
344 | pex=320.; |
---|
345 | pos=.14; |
---|
346 | wid=7.e-6; |
---|
347 | } |
---|
348 | else if(tZ==4 && tN==5) |
---|
349 | { |
---|
350 | pex=600.; |
---|
351 | pos=.132; |
---|
352 | wid=.005; |
---|
353 | } |
---|
354 | else if(tZ==3 && tN==4) |
---|
355 | { |
---|
356 | pex=280.; |
---|
357 | pos=.19; |
---|
358 | wid=.0025; |
---|
359 | } |
---|
360 | else if(tZ==3 && tN==3) |
---|
361 | { |
---|
362 | pex=370.; |
---|
363 | pos=.171; |
---|
364 | wid=.006; |
---|
365 | } |
---|
366 | else if(tZ==2 && tN==1) |
---|
367 | { |
---|
368 | pex=30.; |
---|
369 | pos=.22; |
---|
370 | wid=.0005; |
---|
371 | } |
---|
372 | } |
---|
373 | sigma=CrossSectionFormula(tZ,tN,P,lP); |
---|
374 | if(pex>0.) |
---|
375 | { |
---|
376 | G4double dp=P-pos; |
---|
377 | sigma+=pex*std::exp(dp*dp/wid); |
---|
378 | } |
---|
379 | } |
---|
380 | else |
---|
381 | { |
---|
382 | G4cerr<<"-Warning-G4QNeutronNuclearCrosSect::CSLin:*Bad A* Z="<<tZ<<", N="<<tN<<G4endl; |
---|
383 | sigma=0.; |
---|
384 | } |
---|
385 | if(sigma<0.) return 0.; |
---|
386 | return sigma; |
---|
387 | } |
---|
388 | |
---|
389 | // Calculation formula for proton-nuclear inelastic cross-section (mb) log(P in GeV/c) |
---|
390 | G4double G4QNeutronNuclearCrossSection::CrossSectionLog(G4int tZ, G4int tN, G4double lP) |
---|
391 | { |
---|
392 | G4double P=std::exp(lP); |
---|
393 | return CrossSectionFormula(tZ, tN, P, lP); |
---|
394 | } |
---|
395 | // Calculation formula for proton-nuclear inelastic cross-section (mb) log(P in GeV/c) |
---|
396 | G4double G4QNeutronNuclearCrossSection::CrossSectionFormula(G4int tZ, G4int tN, |
---|
397 | G4double P, G4double lP) |
---|
398 | { |
---|
399 | G4double sigma=0.; |
---|
400 | if(tZ==1 && !tN) // np=pp interaction |
---|
401 | { |
---|
402 | G4double sp=std::sqrt(P); |
---|
403 | G4double ds=lP-4.2; |
---|
404 | G4double dp=P-.35; |
---|
405 | G4double d3=dp*dp*dp; |
---|
406 | sigma=(33.+.2*ds*ds)/(1.+.4/sp)/(1.+.5/d3/d3); |
---|
407 | } |
---|
408 | else if(tZ<93 && tN<146) // General solution |
---|
409 | { |
---|
410 | G4double lP=std::log(P); |
---|
411 | G4double d=lP-4.2; |
---|
412 | G4double p2=P*P; |
---|
413 | G4double p4=p2*p2; |
---|
414 | G4double a=tN+tZ; // A of the target |
---|
415 | G4double al=std::log(a); |
---|
416 | G4double a2=a*a; |
---|
417 | G4double a4=a2*a2; |
---|
418 | G4double a8=a4*a4; |
---|
419 | G4double a12=a8*a4; |
---|
420 | G4double a16=a8*a8; |
---|
421 | G4double c=170./(1.+5./std::exp(al*1.6)); |
---|
422 | G4double dl=al-2.8; |
---|
423 | G4double r=.3+.2*dl*dl; |
---|
424 | G4double g=40.*std::exp(al*0.712)/(1.+12.2/a)/(1.+34./a2); |
---|
425 | G4double e=318.+a4/(1.+.0015*a4/std::exp(al*0.09))/(1.+4.e-28*a12)+ |
---|
426 | 8.e-18/(1./a16+1.3e-20)/(1.+1.e-21*a12); |
---|
427 | G4double s=3.57+.009*a2/(1.+.0001*a2*a); |
---|
428 | G4double h=(.01/a4+2.5e-6/a)*(1.+7.e-8*a4)/(1.+6.e7/a12/a2); |
---|
429 | sigma=(c+d*d)/(1.+r/p4)+(g+e*std::exp(-s*P))/(1.+h/p4/p4); |
---|
430 | } |
---|
431 | else |
---|
432 | { |
---|
433 | G4cerr<<"-Warning-G4QNeutronNuclearCroSect::CSForm:*Bad A* Z="<<tZ<<", N="<<tN<<G4endl; |
---|
434 | sigma=0.; |
---|
435 | } |
---|
436 | if(sigma<0.) return 0.; |
---|
437 | return sigma; |
---|
438 | } |
---|