Gabriele Cosmo
139 lines
5.4 KiB
C++
139 lines
5.4 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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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. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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/*
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* Interface to calculation of the Fermi density effect as per the method
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* described in:
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*
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* R. M. Sternheimer, M. J. Berger, and S. M. Seltzer. Density
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* effect for the ionization loss of charged particles in various sub-
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* stances. Atom. Data Nucl. Data Tabl., 30:261, 1984.
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*
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* Which (among other Sternheimer references) builds on:
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*
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* R. M. Sternheimer. The density effect for ionization loss in
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* materials. Phys. Rev., 88:851859, 1952.
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*
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* The returned values of delta are directly from the Sternheimer calculation,
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* and not Sternheimer's popular three-part approximate parameterization
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* introduced in the same paper.
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*
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* Author: Matthew Strait <straitm@umn.edu> 2019
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*/
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#ifndef G4DensityEffectCalculator_HH
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#define G4DensityEffectCalculator_HH
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#include "globals.hh"
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class G4Material;
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class G4DensityEffectCalculator
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{
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public:
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G4DensityEffectCalculator(const G4Material*, G4int);
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~G4DensityEffectCalculator();
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// The Sternheimer 'x' defined as log10(p/m) == log10(beta*gamma).
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G4double ComputeDensityCorrection(G4double x);
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private:
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/*
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* Given a material defined in 'par' with a plasma energy, mean excitation
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* energy, and set of atomic energy levels ("oscillator frequencies") with
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* occupation fractions ("oscillation strengths"), solve for the Sternheimer
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* adjustment factor (Sternheimer 1984 eq 8) and record (into 'par') the values
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* of the adjusted oscillator frequencies and Sternheimer constants l_i.
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* After doing this, 'par' is ready for a calculation of delta for an
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* arbitrary particle energy. Returns true on success, false on failure.
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*/
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G4double FermiDeltaCalculation(G4double x);
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G4double Newton(G4double x0, G4bool first);
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G4double DFRho(G4double);
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G4double FRho(G4double);
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G4double DEll(G4double);
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G4double Ell(G4double);
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G4double DeltaOnceSolved(G4double);
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const G4Material* fMaterial;
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G4int fVerbose{0};
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G4int fWarnings{0};
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// Number of energy levels. If a single element, this is the number
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// of subshells. If several elements, this is the sum of the number
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// of subshells. In principle, could include levels for molecular
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// orbitals or other non-atomic states. The last level is always
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// the conduction band. If the material is an insulator, set the
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// oscillator strength for that level to zero and the energy to
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// any value.
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const G4int nlev;
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G4double fConductivity;
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// Current Sternheimer 'x' defined as log10(p/m) == log10(beta*gamma).
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G4double sternx;
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// The plasma energy of the material in eV, which is simply
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// 28.816 sqrt(density Z/A), with density in g/cc.
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G4double plasmaE;
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// The mean excitation energy of the material in eV, i.e. the 'I' in the
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// Bethe energy loss formula.
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G4double meanexcite;
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// Sternheimer's "oscillator strengths", which are simply the fraction
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// of electrons in a given energy level. For a single element, this is
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// the fraction of electrons in a subshell. For a compound or mixture,
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// it is weighted by the number fraction of electrons contributed by
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// each element, e.g. for water, oxygen's electrons are given 8/10 of the
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// weight.
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G4double* sternf;
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// Energy levels. Can be found for free atoms in, e.g., T. A. Carlson.
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// Photoelectron and Auger Spectroscopy. Plenum Press, New York and London,
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// 1985. Available in a convenient form in G4AtomicShells.cc.
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//
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// Sternheimer 1984 implies that the energy level for conduction electrons
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// (the final element of this array) should be set to zero, although the
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// computation could be run with other values.
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G4double* levE;
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/***** Results of intermediate calculations *****/
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// The Sternheimer parameters l_i which appear in Sternheimer 1984 eq(1).
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G4double* sternl;
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// The adjusted energy levels, as found using Sternheimer 1984 eq(8).
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G4double* sternEbar;
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};
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#endif
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