Gabriele Cosmo
77 lines
2.5 KiB
C++
77 lines
2.5 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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//
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#ifndef G4FermiMomentum_h
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#define G4FermiMomentum_h 1
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#include "globals.hh"
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#include "G4ThreeVector.hh"
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#include "Randomize.hh"
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class G4FermiMomentum
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{
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public:
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G4FermiMomentum();
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~G4FermiMomentum();
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inline void Init(G4double anA, G4double aZ) {theA = anA; theZ = aZ;}
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inline G4double GetFermiMomentum(G4double density)
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{
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return constofpmax * cbrt(density * theA);
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}
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inline G4ThreeVector GetMomentum(G4double density,
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G4double maxMomentum=-1.)
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{
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if (maxMomentum < 0 ) maxMomentum=GetFermiMomentum(density);
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G4ThreeVector p;
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do {
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p=G4ThreeVector(2.*G4UniformRand()-1.,
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2.*G4UniformRand()-1.,
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2.*G4UniformRand()-1.);
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} while ( p.mag() > 1. );
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return p*maxMomentum;
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}
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private:
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G4double cbrt(G4double x) { return pow(x,1./3.); }
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private:
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G4double theA;
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G4double theZ;
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// pmax= hbar * c * ( 3* pi**2 * rho )**(1/3) =
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// hbar * c * ( 3* pi**2 )**(1/3) * rho**(1/3)=
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// constofpmax * rho**(1/3)
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G4double constofpmax;
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};
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#endif
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