// // ******************************************************************** // * License and Disclaimer * // * * // * The Geant4 software is copyright of the Copyright Holders of * // * the Geant4 Collaboration. It is provided under the terms and * // * conditions of the Geant4 Software License, included in the file * // * LICENSE and available at http://cern.ch/geant4/license . These * // * include a list of copyright holders. * // * * // * Neither the authors of this software system, nor their employing * // * institutes,nor the agencies providing financial support for this * // * work make any representation or warranty, express or implied, * // * regarding this software system or assume any liability for its * // * use. Please see the license in the file LICENSE and URL above * // * for the full disclaimer and the limitation of liability. * // * * // * This code implementation is the result of the scientific and * // * technical work of the GEANT4 collaboration. * // * By using, copying, modifying or distributing the software (or * // * any work based on the software) you agree to acknowledge its * // * use in resulting scientific publications, and indicate your * // * acceptance of all terms of the Geant4 Software license. * // ******************************************************************** // // // $Id$ // // // GEANT4 virtual class: G4VQCrossSection -- header file // M.V. Kossov, CERN-ITEP(Moscow), 4-FEB-2004 // The last update: M.V. Kossov, CERN/ITEP (Moscow) 27-Nov-04 // // Short description: this G4 virtual class is made for the cross section // classes of the CHIPS model, which calculate the cross section for the // particular Element (virtual GetCrossSection member function). Each of the // CHIPS cross section classes creates its own Dynamic Associative Memory // Data Base (DAMDB) for the already used isotopes. For all of them thay use the // same algorithm. Common member functions of this algorithm can be in this // basic virtual class. Any CHIPS cross section class MUST inherit from this virtual // G4VQCrossSection class. In the G4QCollision class the general G4VQCrossSection* // pointer is connected to this or that CHIPS cross section class (depending on the // projectile particle), so each of the CHIPS cross section class must be // an evolving singletone. The singletone nature can not be realized in the // virtual class. So each derived CS class must have // static G4VQCrossSection* GetPointer(); // Gives a pointer to the singletone // static function, which is defined in the *.cc file as // // Returns Pointer to the G4VQCrossSection class // G4VQCrossSection* G4VQCrossSection::GetPointer() // { // static G4QXCrossSection theCrossSection; //***Static body of the Cross Section*** // return &theCrossSection; // } // the line // //virtual static G4VQCrossSection* GetPointer(); // Gives a pointer to the singletone // Reminds about this necesity, but in C++ the virtual static function can not be // realised, so the static function can not be realised in the interface. Developers // must take care of this themselves because this member fuction is called to get a pointer // to the singletone in the G4QCollision class. So there is an agreement to // make a separate CS class for each projectile particle, e.g. while the (pi-)d // and (pi+)d (as well as [n,z] and [z,n]) cross sections) are almost equal, // they must be calculated in different classes: G4QPiMinusCrossSection and // G4QPiPlusCrossSections. For the ion-nuclear cross sections there should exist only // one G4QIonCrossSection class with a huge (#0f isotopes times #of already produced // ions) DAMDB or a general analitic formula with parameters. --- December 2004 --- // ----------------------------------------------------------------------- // At present (25.11.04) for the test purposes this virtual class is created // for ohly G4QPhotonCrossSection, G4QElectronCrossSection, G4QMuonCrossSection, // G4QTauCrossSection and G4QProtonCrossSection (only for pp collisions now). // **************************************************************************************** // ********* This HEADER is temporary moved from the photolepton_hadron directory ********* // ******* DO NOT MAKE ANY CHANGE! With time it'll move back to photolepton...(M.K.) ****** // **************************************************************************************** // Short description: a basic class for all CHIPS reaction cross-sections. // ----------------------------------------------------------------------- #ifndef G4VQCrossSection_h #define G4VQCrossSection_h 1 #include "G4ParticleTable.hh" #include "G4NucleiProperties.hh" #include <vector> #include "Randomize.hh" class G4VQCrossSection { protected: G4VQCrossSection() {;} // for each particle a separate instance of G4QCollision should be // used (and inside use a separate instance of G4Q*CrossSection) public: virtual ~G4VQCrossSection() {;}// for each particle separate instance of G4QXCrossSection //@@ can be improved in future)// should be used and inside a separate istance of CS's // Set the new tolerance (abs(p_old/p_new-1)<tolerance) static void setTolerance(G4double tol){tolerance=tol;}// Set NewTolerance for SameCrosSec // At present momentum (pMom) must be in GeV (@@ Units) virtual G4double GetCrossSection(G4bool, G4double, G4int, G4int, G4int pPDG=0) {return G4double(pPDG);} virtual G4double ThresholdEnergy(G4int Z, G4int N, G4int PDG=0); // Gives 0 by default // Define in the derived class, F=0 - create AMDB, F=-1 - read AMDB, F=1 - update AMDB virtual G4double CalculateCrossSection(G4bool CS, G4int F, G4int I, G4int PDG, G4int tgZ, G4int tgN, G4double pMom)=0;//*** PURE VIRTUAL *** virtual G4double GetLastTOTCS(); // LastCalculated total cross-section (total elastic) virtual G4double GetLastQELCS(); // LastCalculated quasielastic cross-section (quasifree) virtual G4double GetDirectPart(G4double Q2); // DirectInteraction with QuarkPartons (nuA) virtual G4double GetNPartons(G4double Q2); // #ofQuarkPartons in nonPerturbatPhaseSp(nuA) // Subroutines for the t-chanel processes with a leader (DIS, Elastic, Quasielastic etc.) virtual G4double GetExchangeEnergy(); // Returns energy of the t-chanel particle (gam,pi) virtual G4double GetExchangeT(G4int tZ, G4int tN, G4int pPDG); // -t=Q2 for hadronic virtual G4double GetSlope(G4int tZ, G4int tN, G4int pPDG); // B-slope of the maim maximum virtual G4double GetHMaxT(); // max(-t=Q2)/2 for hadronic (MeV^2) virtual G4double GetExchangeQ2(G4double nu=0); // Q2 for lepto-nuclear reactions virtual G4double GetVirtualFactor(G4double nu, G4double Q2); // ReductionFactor (leptA) virtual G4double GetQEL_ExchangeQ2(); // Get randomized Q2 for quasi-elastic scattering virtual G4double GetNQE_ExchangeQ2(); // Get randomized Q2 for non quasi-elastic scat. virtual G4int GetExchangePDGCode(); // PDGCode of the Exchange Particle (Pi0 by default) // Body: Basic Parameters of DAMDB (each derived class can add it's own values) // ----------------------------------------------------------------------------- // The basic scheme of the DAMDB coveres the cross section for isotopes with fixed // Z (lastZ - number of protons) and N (lastN - number of neutrons) from the // Threshold momentum (TH) up to infinity. The cross section is first (Tab.1) // tabulated from the threshold till the boundary momentum (BP). The Tab.1 is // the function of the momentum (p) with the N1 elements. The N1 elements can be // not all different from zero. The first non-zero element is F1, the last non-zero // element is L1. If TH#0 the Tab.1 can be skipped. It is defined by N1=F1=L1=0 and // BP=TH. The Tab.1 is the function of the ln(p) with N2 elements (F2 is the first // non-zero element, L2 is the last non-zero element) from BP up tp MP. Both Tab.1 // and Tab.2 are calculated when the projectile of the class meet the corresponding // ion. After that the tables are stored in the DAMDB for the fast calculations. To // avoid a complete calculation of the tables in the low energy calculation case, // the lastP momentum is used. The tables are calculated only till the momentum, // which already appeared in the simulation for this projectile and this isotope. // If the momentum above MP appeared, then the extrapolation function is calculated. // So, if lastP>MP it means that the cross section is defined for all energies above // TH. All parameters and pointers to arrays MUST be stored (F=0), updated (F=1) and // retrieved (F=-1) by the derived class in the CalculateCrossSection(F,I,N,Z,P) // function. The parameters are used for the immediate result: if the cross section is // calculated for the same Z, N, and fabs(p-lastP)/lastP<.001 (? - a parameter), the same // cross section (lastCS) is returned, if p<lastTH, then the 0 cross section is returned. // It helps to avoid double counting. The derived class can have only the approximation // functions, but such class is too slow, as it calculates the arythmetic equations each // time, when it is necessary to get a new cross section. So it is reasonable to // precalculate the tables, store them in memory, remember the pointers to these // functions and just interpolate them in the range of the most frequent energies (use // a LinearFit inline function of this virtual class for that). Starting some high // momentum (PM) the functional calculations are unavoidable, but fortunately they are // not frequent. In case of the ion-nuclear cross section the functional approach can // be reasonable, because tabulated cross-sections demand too much memory. // // ----------------------------------------------------------------------------- protected: G4double LinearFit(G4double X, G4int N, G4double* XN, G4double* YN); G4double EquLinearFit(G4double X, G4int N, G4double X0, G4double DX, G4double* Y); static G4double tolerance;// relative tolerance in momentum to get old CroSec }; #endif