Gabriele Cosmo
1170 lines
40 KiB
C++
1170 lines
40 KiB
C++
//
|
|
// ********************************************************************
|
|
// * 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: G4UrbanMscModel.cc,v 1.47 2007/03/07 15:44:42 urban Exp $
|
|
// GEANT4 tag $Name: geant4-08-03 $
|
|
//
|
|
// -------------------------------------------------------------------
|
|
//
|
|
// GEANT4 Class file
|
|
//
|
|
//
|
|
// File name: G4UrbanMscModel
|
|
//
|
|
// Author: Laszlo Urban
|
|
//
|
|
// Creation date: 03.03.2001
|
|
//
|
|
// Modifications:
|
|
//
|
|
// 27-03-03 Move model part from G4MultipleScattering80 (V.Ivanchenko)
|
|
// 23-05-03 important change in angle distribution for muons/hadrons
|
|
// the central part now is similar to the Highland parametrization +
|
|
// minor correction in angle sampling algorithm (for all particles)
|
|
// (L.Urban)
|
|
// 30-05-03 misprint in SampleCosineTheta corrected(L.Urban)
|
|
// 27-03-03 Rename (V.Ivanchenko)
|
|
// 05-08-03 angle distribution has been modified (L.Urban)
|
|
// 06-11-03 precision problems solved for high energy (PeV) particles
|
|
// change in the tail of the angular distribution
|
|
// highKinEnergy is set to 100 PeV (L.Urban)
|
|
//
|
|
// 10-11-03 highKinEnergy is set back to 100 TeV, some tail tuning +
|
|
// cleaning (L.Urban)
|
|
// 26-11-03 correction in TrueStepLength :
|
|
// trueLength <= currentRange (L.Urban)
|
|
// 01-03-04 signature changed in SampleCosineTheta,
|
|
// energy dependence calculations has been simplified,
|
|
// 11-03-04 corrections in GeomPathLength,TrueStepLength,
|
|
// SampleCosineTheta
|
|
// 23-04-04 true -> geom and geom -> true transformation has been
|
|
// rewritten, changes in the angular distribution (L.Urban)
|
|
// 19-07-04 correction in SampleCosineTheta in order to avoid
|
|
// num. precision problems at high energy/small step(L.Urban)
|
|
// 17-08-04 changes in the angle distribution (slightly modified
|
|
// Highland formula for the width of the central part,
|
|
// changes in the numerical values of some other parameters)
|
|
// ---> approximately step independent distribution (L.Urban)
|
|
// 21-09-04 change in the tail of the angular distribution (L.Urban)
|
|
//
|
|
// 03-11-04 precision problem for very high energy ions and small stepsize
|
|
// solved in SampleCosineTheta (L.Urban).
|
|
// 15-04-05 optimize internal interface
|
|
// add SampleSecondaries method (V.Ivanchenko)
|
|
// 11-08-05 computation of lateral correlation added (L.Urban)
|
|
// 02-10-05 nuclear size correction computation removed, the correction
|
|
// included in the (theoretical) tabulated values (L.Urban)
|
|
// 17-01-06 computation of tail changed in SampleCosineTheta (l.Urban)
|
|
// 16-02-06 code cleaning + revised 'z' sampling (L.Urban)
|
|
// 17-02-06 Save table of transport cross sections not mfp (V.Ivanchenko)
|
|
// 07-03-06 Create G4UrbanMscModel and move there step limit
|
|
// calculation (V.Ivanchenko)
|
|
// 23-03-06 Bugfix in SampleCosineTheta method (L.Urban)
|
|
// 10-05-06 SetMscStepLimitation at initialisation (V.Ivantchenko)
|
|
// 11-05-06 name of data member safety changed to presafety, some new data
|
|
// members added (frscaling1,frscaling2,tlimitminfix,nstepmax)
|
|
// changes in ComputeTruePathLengthLimit,SampleCosineTheta (L.Urban)
|
|
// 17-05-06 parameters of theta0 in SampleCosineTheta changed
|
|
// c_highland 13.6*MeV ---> 13.26*MeV,
|
|
// corr_highland 0.555 ---> 0.54,
|
|
// value of data member geommin changed (5 nm -> 1 nm) (L.Urban)
|
|
// 13-10-06 data member factail removed, data member tkinlimit changed
|
|
// to lambdalimit,
|
|
// new data members tgeom,tnow,skin,skindepth,Zeff,geomlimit
|
|
// G4double GeomLimit(const G4Track& track) changed to
|
|
// void GeomLimit(const G4Track& track)
|
|
// - important changes in ComputeTruePathLengthLimit:
|
|
// possibility to have very small step(s) with single scattering
|
|
// before boundary crossing (with skin > 0)
|
|
// - changes in SampleCosineTheta :
|
|
// single scattering if step <= stepmin, parameter theta0
|
|
// slightly modified, tail modified (L.Urban)
|
|
// 20-10-06 parameter theta0 now computed in the (public)
|
|
// function ComputeTheta0,
|
|
// single scattering modified allowing not small
|
|
// angles as well (L.Urban)
|
|
// 23-10-06 correction in SampleSecondaries, now safety update
|
|
// computed in a simpler/faster way (L.Urban)
|
|
// 06-11-06 corrections in ComputeTruePathLengthLimit, results are
|
|
// more stable in calorimeters (L.Urban)
|
|
// 07-11-06 fix in GeomPathLength and SampleCosineTheta (L.Urban)
|
|
// 15-11-06 bugfix in SampleCosineTheta (L.Urban)
|
|
// 20-11-06 bugfix in single scattering part of SampleCosineTheta,
|
|
// single scattering just before boundary crossing now (L.Urban)
|
|
// 04-12-06 fix in ComputeTruePathLengthLimit (L.Urban)
|
|
// 17-01-07 remove LocatePoint from GeomLimit method (V.Ivanchenko)
|
|
// 19-01-07 fix of true < geom problem (L.Urban)
|
|
// 25-01-07 add protections from NaN vaues and for zero geometry step (VI)
|
|
// 31-01-07 correction in SampleCosineTheta: screening parameter
|
|
// corrected in single/plural scattering +
|
|
// code cleaning (L.Urban)
|
|
// 01-02-07 restore logic inside ComputeTrueStepLength (V.Ivanchenko)
|
|
// 06-02-07 Move SetMscStepLimitation method into the source, add there
|
|
// reinitialisation of some private members, add protection inside
|
|
// SampleDisplacement(VI)
|
|
// 07-02-07 fix single scattering for heavy particles, now skin=1 can be used
|
|
// for heavy particles as well (L.Urban)
|
|
// 08-02-07 randomization of tlimit removed (L.Urban)
|
|
// 11-02-07 modified stepping algorithm for skin=0
|
|
// 15-02-07 new data member: smallstep, small steps with single scattering
|
|
// before + after boundary for skin > 1
|
|
// 23-02-07 use tPathLength inside ComputeStep instead of geombig
|
|
// 24-02-07 step reduction before boundary for 'small' geomlimit only
|
|
// 03-03-07 single scattering around boundaries only (L.Urban)
|
|
// 07-03-07 bugfix in ComputeTruePathLengthLimit (for skin > 0.) (L.Urban)
|
|
//
|
|
|
|
// Class Description:
|
|
//
|
|
// Implementation of the model of multiple scattering based on
|
|
// H.W.Lewis Phys Rev 78 (1950) 526 and others
|
|
|
|
// -------------------------------------------------------------------
|
|
//
|
|
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
#include "G4UrbanMscModel.hh"
|
|
#include "Randomize.hh"
|
|
#include "G4Electron.hh"
|
|
#include "G4LossTableManager.hh"
|
|
#include "G4ParticleChangeForMSC.hh"
|
|
#include "G4TransportationManager.hh"
|
|
#include "G4Navigator.hh"
|
|
|
|
#include "G4Poisson.hh"
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
using namespace std;
|
|
|
|
G4UrbanMscModel::G4UrbanMscModel(G4double m_facrange, G4double m_dtrl,
|
|
G4double m_lambdalimit,
|
|
G4double m_facgeom,G4double m_skin,
|
|
G4bool m_samplez, G4bool m_stepAlg,
|
|
const G4String& nam)
|
|
: G4VEmModel(nam),
|
|
dtrl(m_dtrl),
|
|
lambdalimit(m_lambdalimit),
|
|
facrange(m_facrange),
|
|
facgeom(m_facgeom),
|
|
skin(m_skin),
|
|
samplez(m_samplez),
|
|
steppingAlgorithm(m_stepAlg),
|
|
isInitialized(false)
|
|
{
|
|
taubig = 8.0;
|
|
tausmall = 1.e-20;
|
|
taulim = 1.e-6;
|
|
currentTau = taulim;
|
|
tlimitminfix = 1.e-6*mm;
|
|
stepmin = tlimitminfix;
|
|
skindepth = skin*stepmin;
|
|
smallstep = 1.e10;
|
|
currentRange = 0. ;
|
|
frscaling2 = 0.25;
|
|
frscaling1 = 1.-frscaling2;
|
|
tlimit = 1.e10*mm;
|
|
tlimitmin = 10.*tlimitminfix;
|
|
tnow = 10.*tlimitminfix;
|
|
nstepmax = 25.;
|
|
geombig = 1.e50*mm;
|
|
geommin = 1.e-3*mm;
|
|
geomlimit = geombig;
|
|
presafety = 0.*mm;
|
|
facsafety = 0.25;
|
|
Zeff = 1.;
|
|
particle = 0;
|
|
theManager = G4LossTableManager::Instance();
|
|
inside = false;
|
|
insideskin = false;
|
|
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4UrbanMscModel::~G4UrbanMscModel()
|
|
{
|
|
delete safetyHelper;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
void G4UrbanMscModel::Initialise(const G4ParticleDefinition* p,
|
|
const G4DataVector&)
|
|
{
|
|
if(isInitialized) return;
|
|
// set values of some data members
|
|
SetParticle(p);
|
|
|
|
if (pParticleChange)
|
|
fParticleChange = reinterpret_cast<G4ParticleChangeForMSC*>(pParticleChange);
|
|
else
|
|
fParticleChange = new G4ParticleChangeForMSC();
|
|
|
|
navigator = G4TransportationManager::GetTransportationManager()
|
|
->GetNavigatorForTracking();
|
|
|
|
safetyHelper= new G4SafetyHelper();
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
void G4UrbanMscModel::SetMscStepLimitation(G4bool alg, G4double factor)
|
|
{
|
|
steppingAlgorithm = alg;
|
|
facrange = factor;
|
|
|
|
// reinitialisation
|
|
stepmin = tlimitminfix;
|
|
skindepth = skin*stepmin;
|
|
tlimitmin = 10.*tlimitminfix;
|
|
tnow = 10.*tlimitminfix;
|
|
inside = false;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeCrossSectionPerAtom(
|
|
const G4ParticleDefinition* part,
|
|
G4double KineticEnergy,
|
|
G4double AtomicNumber,G4double,
|
|
G4double, G4double)
|
|
{
|
|
const G4double sigmafactor = twopi*classic_electr_radius*classic_electr_radius;
|
|
const G4double epsfactor = 2.*electron_mass_c2*electron_mass_c2*
|
|
Bohr_radius*Bohr_radius/(hbarc*hbarc);
|
|
const G4double epsmin = 1.e-4 , epsmax = 1.e10;
|
|
|
|
const G4double Zdat[15] = { 4., 6., 13., 20., 26., 29., 32., 38., 47.,
|
|
50., 56., 64., 74., 79., 82. };
|
|
|
|
const G4double Tdat[22] = { 100*eV, 200*eV, 400*eV, 700*eV,
|
|
1*keV, 2*keV, 4*keV, 7*keV,
|
|
10*keV, 20*keV, 40*keV, 70*keV,
|
|
100*keV, 200*keV, 400*keV, 700*keV,
|
|
1*MeV, 2*MeV, 4*MeV, 7*MeV,
|
|
10*MeV, 20*MeV};
|
|
|
|
// corr. factors for e-/e+ lambda for T <= Tlim
|
|
G4double celectron[15][22] =
|
|
{{1.125,1.072,1.051,1.047,1.047,1.050,1.052,1.054,
|
|
1.054,1.057,1.062,1.069,1.075,1.090,1.105,1.111,
|
|
1.112,1.108,1.100,1.093,1.089,1.087 },
|
|
{1.408,1.246,1.143,1.096,1.077,1.059,1.053,1.051,
|
|
1.052,1.053,1.058,1.065,1.072,1.087,1.101,1.108,
|
|
1.109,1.105,1.097,1.090,1.086,1.082 },
|
|
{2.833,2.268,1.861,1.612,1.486,1.309,1.204,1.156,
|
|
1.136,1.114,1.106,1.106,1.109,1.119,1.129,1.132,
|
|
1.131,1.124,1.113,1.104,1.099,1.098 },
|
|
{3.879,3.016,2.380,2.007,1.818,1.535,1.340,1.236,
|
|
1.190,1.133,1.107,1.099,1.098,1.103,1.110,1.113,
|
|
1.112,1.105,1.096,1.089,1.085,1.098 },
|
|
{6.937,4.330,2.886,2.256,1.987,1.628,1.395,1.265,
|
|
1.203,1.122,1.080,1.065,1.061,1.063,1.070,1.073,
|
|
1.073,1.070,1.064,1.059,1.056,1.056 },
|
|
{9.616,5.708,3.424,2.551,2.204,1.762,1.485,1.330,
|
|
1.256,1.155,1.099,1.077,1.070,1.068,1.072,1.074,
|
|
1.074,1.070,1.063,1.059,1.056,1.052 },
|
|
{11.72,6.364,3.811,2.806,2.401,1.884,1.564,1.386,
|
|
1.300,1.180,1.112,1.082,1.073,1.066,1.068,1.069,
|
|
1.068,1.064,1.059,1.054,1.051,1.050 },
|
|
{18.08,8.601,4.569,3.183,2.662,2.025,1.646,1.439,
|
|
1.339,1.195,1.108,1.068,1.053,1.040,1.039,1.039,
|
|
1.039,1.037,1.034,1.031,1.030,1.036 },
|
|
{18.22,10.48,5.333,3.713,3.115,2.367,1.898,1.631,
|
|
1.498,1.301,1.171,1.105,1.077,1.048,1.036,1.033,
|
|
1.031,1.028,1.024,1.022,1.021,1.024 },
|
|
{14.14,10.65,5.710,3.929,3.266,2.453,1.951,1.669,
|
|
1.528,1.319,1.178,1.106,1.075,1.040,1.027,1.022,
|
|
1.020,1.017,1.015,1.013,1.013,1.020 },
|
|
{14.11,11.73,6.312,4.240,3.478,2.566,2.022,1.720,
|
|
1.569,1.342,1.186,1.102,1.065,1.022,1.003,0.997,
|
|
0.995,0.993,0.993,0.993,0.993,1.011 },
|
|
{22.76,20.01,8.835,5.287,4.144,2.901,2.219,1.855,
|
|
1.677,1.410,1.224,1.121,1.073,1.014,0.986,0.976,
|
|
0.974,0.972,0.973,0.974,0.975,0.987 },
|
|
{50.77,40.85,14.13,7.184,5.284,3.435,2.520,2.059,
|
|
1.837,1.512,1.283,1.153,1.091,1.010,0.969,0.954,
|
|
0.950,0.947,0.949,0.952,0.954,0.963 },
|
|
{65.87,59.06,15.87,7.570,5.567,3.650,2.682,2.182,
|
|
1.939,1.579,1.325,1.178,1.108,1.014,0.965,0.947,
|
|
0.941,0.938,0.940,0.944,0.946,0.954 },
|
|
{55.60,47.34,15.92,7.810,5.755,3.767,2.760,2.239,
|
|
1.985,1.609,1.343,1.188,1.113,1.013,0.960,0.939,
|
|
0.933,0.930,0.933,0.936,0.939,0.949 }};
|
|
|
|
G4double cpositron[15][22] = {
|
|
{2.589,2.044,1.658,1.446,1.347,1.217,1.144,1.110,
|
|
1.097,1.083,1.080,1.086,1.092,1.108,1.123,1.131,
|
|
1.131,1.126,1.117,1.108,1.103,1.100 },
|
|
{3.904,2.794,2.079,1.710,1.543,1.325,1.202,1.145,
|
|
1.122,1.096,1.089,1.092,1.098,1.114,1.130,1.137,
|
|
1.138,1.132,1.122,1.113,1.108,1.102 },
|
|
{7.970,6.080,4.442,3.398,2.872,2.127,1.672,1.451,
|
|
1.357,1.246,1.194,1.179,1.178,1.188,1.201,1.205,
|
|
1.203,1.190,1.173,1.159,1.151,1.145 },
|
|
{9.714,7.607,5.747,4.493,3.815,2.777,2.079,1.715,
|
|
1.553,1.353,1.253,1.219,1.211,1.214,1.225,1.228,
|
|
1.225,1.210,1.191,1.175,1.166,1.174 },
|
|
{17.97,12.95,8.628,6.065,4.849,3.222,2.275,1.820,
|
|
1.624,1.382,1.259,1.214,1.202,1.202,1.214,1.219,
|
|
1.217,1.203,1.184,1.169,1.160,1.151 },
|
|
{24.83,17.06,10.84,7.355,5.767,3.707,2.546,1.996,
|
|
1.759,1.465,1.311,1.252,1.234,1.228,1.238,1.241,
|
|
1.237,1.222,1.201,1.184,1.174,1.159 },
|
|
{23.26,17.15,11.52,8.049,6.375,4.114,2.792,2.155,
|
|
1.880,1.535,1.353,1.281,1.258,1.247,1.254,1.256,
|
|
1.252,1.234,1.212,1.194,1.183,1.170 },
|
|
{22.33,18.01,12.86,9.212,7.336,4.702,3.117,2.348,
|
|
2.015,1.602,1.385,1.297,1.268,1.251,1.256,1.258,
|
|
1.254,1.237,1.214,1.195,1.185,1.179 },
|
|
{33.91,24.13,15.71,10.80,8.507,5.467,3.692,2.808,
|
|
2.407,1.873,1.564,1.425,1.374,1.330,1.324,1.320,
|
|
1.312,1.288,1.258,1.235,1.221,1.205 },
|
|
{32.14,24.11,16.30,11.40,9.015,5.782,3.868,2.917,
|
|
2.490,1.925,1.596,1.447,1.391,1.342,1.332,1.327,
|
|
1.320,1.294,1.264,1.240,1.226,1.214 },
|
|
{29.51,24.07,17.19,12.28,9.766,6.238,4.112,3.066,
|
|
2.602,1.995,1.641,1.477,1.414,1.356,1.342,1.336,
|
|
1.328,1.302,1.270,1.245,1.231,1.233 },
|
|
{38.19,30.85,21.76,15.35,12.07,7.521,4.812,3.498,
|
|
2.926,2.188,1.763,1.563,1.484,1.405,1.382,1.371,
|
|
1.361,1.330,1.294,1.267,1.251,1.239 },
|
|
{49.71,39.80,27.96,19.63,15.36,9.407,5.863,4.155,
|
|
3.417,2.478,1.944,1.692,1.589,1.480,1.441,1.423,
|
|
1.409,1.372,1.330,1.298,1.280,1.258 },
|
|
{59.25,45.08,30.36,20.83,16.15,9.834,6.166,4.407,
|
|
3.641,2.648,2.064,1.779,1.661,1.531,1.482,1.459,
|
|
1.442,1.400,1.354,1.319,1.299,1.272 },
|
|
{56.38,44.29,30.50,21.18,16.51,10.11,6.354,4.542,
|
|
3.752,2.724,2.116,1.817,1.692,1.554,1.499,1.474,
|
|
1.456,1.412,1.364,1.328,1.307,1.282 }};
|
|
|
|
//data/corrections for T > Tlim
|
|
G4double Tlim = 10.*MeV;
|
|
G4double beta2lim = Tlim*(Tlim+2.*electron_mass_c2)/
|
|
((Tlim+electron_mass_c2)*(Tlim+electron_mass_c2));
|
|
G4double bg2lim = Tlim*(Tlim+2.*electron_mass_c2)/
|
|
(electron_mass_c2*electron_mass_c2);
|
|
|
|
G4double sig0[15] = {0.2672*barn, 0.5922*barn, 2.653*barn, 6.235*barn,
|
|
11.69*barn , 13.24*barn , 16.12*barn, 23.00*barn ,
|
|
35.13*barn , 39.95*barn , 50.85*barn, 67.19*barn ,
|
|
91.15*barn , 104.4*barn , 113.1*barn};
|
|
|
|
G4double hecorr[15] = {120.70, 117.50, 105.00, 92.92, 79.23, 74.510, 68.29,
|
|
57.39, 41.97, 36.14, 24.53, 10.21, -7.855, -16.84,
|
|
-22.30};
|
|
|
|
G4double sigma;
|
|
SetParticle(part);
|
|
|
|
G4double Z23 = 2.*log(AtomicNumber)/3.; Z23 = exp(Z23);
|
|
|
|
// correction if particle .ne. e-/e+
|
|
// compute equivalent kinetic energy
|
|
// lambda depends on p*beta ....
|
|
|
|
G4double eKineticEnergy = KineticEnergy;
|
|
|
|
if((particle->GetParticleName() != "e-") &&
|
|
(particle->GetParticleName() != "e+") )
|
|
{
|
|
G4double TAU = KineticEnergy/mass ;
|
|
G4double c = mass*TAU*(TAU+2.)/(electron_mass_c2*(TAU+1.)) ;
|
|
G4double w = c-2. ;
|
|
G4double tau = 0.5*(w+sqrt(w*w+4.*c)) ;
|
|
eKineticEnergy = electron_mass_c2*tau ;
|
|
}
|
|
|
|
G4double ChargeSquare = charge*charge;
|
|
|
|
G4double eTotalEnergy = eKineticEnergy + electron_mass_c2 ;
|
|
G4double beta2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
|
|
/(eTotalEnergy*eTotalEnergy);
|
|
G4double bg2 = eKineticEnergy*(eTotalEnergy+electron_mass_c2)
|
|
/(electron_mass_c2*electron_mass_c2);
|
|
|
|
G4double eps = epsfactor*bg2/Z23;
|
|
|
|
if (eps<epsmin) sigma = 2.*eps*eps;
|
|
else if(eps<epsmax) sigma = log(1.+2.*eps)-2.*eps/(1.+2.*eps);
|
|
else sigma = log(2.*eps)-1.+1./eps;
|
|
|
|
sigma *= ChargeSquare*AtomicNumber*AtomicNumber/(beta2*bg2);
|
|
|
|
// interpolate in AtomicNumber and beta2
|
|
G4double c1,c2,cc1,cc2,corr;
|
|
|
|
// get bin number in Z
|
|
G4int iZ = 14;
|
|
while ((iZ>=0)&&(Zdat[iZ]>=AtomicNumber)) iZ -= 1;
|
|
if (iZ==14) iZ = 13;
|
|
if (iZ==-1) iZ = 0 ;
|
|
|
|
G4double Z1 = Zdat[iZ];
|
|
G4double Z2 = Zdat[iZ+1];
|
|
G4double ratZ = (AtomicNumber-Z1)*(AtomicNumber+Z1)/
|
|
((Z2-Z1)*(Z2+Z1));
|
|
|
|
if(eKineticEnergy <= Tlim)
|
|
{
|
|
// get bin number in T (beta2)
|
|
G4int iT = 21;
|
|
while ((iT>=0)&&(Tdat[iT]>=eKineticEnergy)) iT -= 1;
|
|
if(iT==21) iT = 20;
|
|
if(iT==-1) iT = 0 ;
|
|
|
|
// calculate betasquare values
|
|
G4double T = Tdat[iT], E = T + electron_mass_c2;
|
|
G4double b2small = T*(E+electron_mass_c2)/(E*E);
|
|
|
|
T = Tdat[iT+1]; E = T + electron_mass_c2;
|
|
G4double b2big = T*(E+electron_mass_c2)/(E*E);
|
|
G4double ratb2 = (beta2-b2small)/(b2big-b2small);
|
|
|
|
if (charge < 0.)
|
|
{
|
|
c1 = celectron[iZ][iT];
|
|
c2 = celectron[iZ+1][iT];
|
|
cc1 = c1+ratZ*(c2-c1);
|
|
|
|
c1 = celectron[iZ][iT+1];
|
|
c2 = celectron[iZ+1][iT+1];
|
|
cc2 = c1+ratZ*(c2-c1);
|
|
|
|
corr = cc1+ratb2*(cc2-cc1);
|
|
|
|
sigma *= sigmafactor/corr;
|
|
}
|
|
else
|
|
{
|
|
c1 = cpositron[iZ][iT];
|
|
c2 = cpositron[iZ+1][iT];
|
|
cc1 = c1+ratZ*(c2-c1);
|
|
|
|
c1 = cpositron[iZ][iT+1];
|
|
c2 = cpositron[iZ+1][iT+1];
|
|
cc2 = c1+ratZ*(c2-c1);
|
|
|
|
corr = cc1+ratb2*(cc2-cc1);
|
|
|
|
sigma *= sigmafactor/corr;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
c1 = bg2lim*sig0[iZ]*(1.+hecorr[iZ]*(beta2-beta2lim))/bg2;
|
|
c2 = bg2lim*sig0[iZ+1]*(1.+hecorr[iZ+1]*(beta2-beta2lim))/bg2;
|
|
if((AtomicNumber >= Z1) && (AtomicNumber <= Z2))
|
|
sigma = c1+ratZ*(c2-c1) ;
|
|
else if(AtomicNumber < Z1)
|
|
sigma = AtomicNumber*AtomicNumber*c1/(Z1*Z1);
|
|
else if(AtomicNumber > Z2)
|
|
sigma = AtomicNumber*AtomicNumber*c2/(Z2*Z2);
|
|
}
|
|
return sigma;
|
|
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeTruePathLengthLimit(
|
|
const G4Track& track,
|
|
G4PhysicsTable* theTable,
|
|
G4double currentMinimalStep)
|
|
{
|
|
theLambdaTable = theTable;
|
|
const G4DynamicParticle* dp = track.GetDynamicParticle();
|
|
SetParticle( dp->GetDefinition() );
|
|
|
|
couple = track.GetMaterialCutsCouple();
|
|
currentMaterialIndex = couple->GetIndex();
|
|
currentKinEnergy = dp->GetKineticEnergy();
|
|
currentRange =
|
|
theManager->GetRangeFromRestricteDEDX(particle,currentKinEnergy,couple);
|
|
lambda0 = GetLambda(currentKinEnergy);
|
|
|
|
tPathLength = currentMinimalStep;
|
|
if(tPathLength > currentRange)
|
|
tPathLength = currentRange;
|
|
|
|
G4StepPoint* sp = track.GetStep()->GetPreStepPoint();
|
|
|
|
presafety = sp->GetSafety();
|
|
G4StepStatus stepStatus = sp->GetStepStatus();
|
|
G4int stepNumber = track.GetCurrentStepNumber();
|
|
if(stepNumber == 1) insideskin = false;
|
|
|
|
// standard version
|
|
//
|
|
if (steppingAlgorithm)
|
|
{
|
|
//for precise simulation for the case without magnatic field
|
|
// small step(s) + single/plural scattering around boundaries
|
|
if(skin > 0.)
|
|
{
|
|
if((stepNumber > 1) && inside)
|
|
return tPathLength;
|
|
|
|
//compute geomlimit and presafety
|
|
GeomLimit(track);
|
|
|
|
insideskin = false;
|
|
smallstep += 1.;
|
|
|
|
if((stepStatus == fGeomBoundary) || (stepNumber == 1))
|
|
{
|
|
if(stepNumber == 1) smallstep = 1.e10;
|
|
else smallstep = 1.;
|
|
|
|
if((stepNumber == 1) && (currentRange < presafety))
|
|
{
|
|
stepmin = tlimitminfix;
|
|
inside = true;
|
|
return tPathLength;
|
|
}
|
|
else
|
|
inside = false;
|
|
|
|
// facrange scaling in lambda
|
|
// not so strong step restriction above lambdalimit
|
|
G4double facr = facrange;
|
|
if(lambda0 > lambdalimit)
|
|
facr *= frscaling1+frscaling2*lambda0/lambdalimit;
|
|
|
|
// constraint from the physics
|
|
if (currentRange > lambda0) tlimit = facr*currentRange;
|
|
else tlimit = facr*lambda0;
|
|
|
|
// constraint from the geometry (if tlimit above is too big)
|
|
G4double tgeom = geombig;
|
|
if(geomlimit > geommin)
|
|
{
|
|
if(stepStatus == fGeomBoundary)
|
|
tgeom = geomlimit/facgeom;
|
|
else
|
|
tgeom = 2.*geomlimit/facgeom;
|
|
}
|
|
|
|
//define stepmin here (it depends on lambda!)
|
|
//rough estimation of lambda_elastic/lambda_transport
|
|
G4double rat = currentKinEnergy/MeV ;
|
|
rat = 1.e-3/(rat*(10.+rat)) ;
|
|
//stepmin ~ lambda_elastic
|
|
stepmin = rat*lambda0;
|
|
skindepth = skin*stepmin;
|
|
|
|
//define tlimitmin
|
|
tlimitmin = lambda0/nstepmax;
|
|
if(tlimitmin < stepmin) tlimitmin = 1.01*stepmin;
|
|
if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix;
|
|
|
|
//lower limit for tlimit
|
|
if(tlimit < tlimitmin) tlimit = tlimitmin;
|
|
|
|
//check against geometry limit
|
|
if(tlimit > tgeom) tlimit = tgeom;
|
|
|
|
//if track starts far from boundaries increase tlimit!
|
|
if(tlimit < facsafety*presafety)
|
|
tlimit = facsafety*presafety ;
|
|
}
|
|
|
|
if(currentRange < presafety)
|
|
{
|
|
inside = true;
|
|
return tPathLength;
|
|
}
|
|
|
|
// shortcut
|
|
if((tPathLength < tlimit) &&
|
|
(tPathLength < presafety))
|
|
return tPathLength;
|
|
|
|
//if track far from boundaries increase tPathLength
|
|
tnow = tlimit;
|
|
if(tlimit < facsafety*presafety)
|
|
tnow = facsafety*presafety ;
|
|
|
|
// step reduction near to boundary
|
|
if(smallstep < skin)
|
|
{
|
|
tnow = stepmin;
|
|
insideskin = true;
|
|
}
|
|
else if(geomlimit < geombig)
|
|
{
|
|
if(geomlimit > skindepth)
|
|
{
|
|
if(tnow > geomlimit-0.999*skindepth)
|
|
tnow = geomlimit-0.999*skindepth;
|
|
}
|
|
else
|
|
{
|
|
insideskin = true;
|
|
if(tnow > stepmin)
|
|
tnow = stepmin;
|
|
}
|
|
}
|
|
|
|
if(tnow < stepmin)
|
|
tnow = stepmin;
|
|
|
|
if(tPathLength > tnow)
|
|
tPathLength = tnow ;
|
|
}
|
|
// for 'normal' simulation with or without magnetic field
|
|
// there no small step/single scattering at boundaries
|
|
else
|
|
{
|
|
if((stepNumber > 1) && inside)
|
|
return tPathLength;
|
|
|
|
// compute presafety again if presafety <= 0 and no boundary
|
|
// i.e. when it is needed for optimization purposes
|
|
if((stepStatus != fGeomBoundary) && (presafety <= 0.))
|
|
{
|
|
presafety = safetyHelper->ComputeSafety(sp->GetPosition());
|
|
if(currentRange < presafety)
|
|
{
|
|
stepmin = tlimitminfix;
|
|
inside = true;
|
|
return tPathLength;
|
|
}
|
|
else
|
|
inside = false;
|
|
}
|
|
|
|
if((stepStatus == fGeomBoundary) || (stepNumber == 1))
|
|
{
|
|
if(stepNumber == 1)
|
|
insideskin = false;
|
|
|
|
// facrange scaling in lambda
|
|
// not so strong step restriction above lambdalimit
|
|
G4double facr = facrange;
|
|
if(lambda0 > lambdalimit)
|
|
facr *= frscaling1+frscaling2*lambda0/lambdalimit;
|
|
|
|
// constraint from the physics
|
|
if (currentRange > lambda0) tlimit = facr*currentRange;
|
|
else tlimit = facr*lambda0;
|
|
|
|
//lower limit for tlimit
|
|
tlimitmin = lambda0/nstepmax;
|
|
if(tlimitmin < tlimitminfix) tlimitmin = tlimitminfix;
|
|
if(tlimit < tlimitmin) tlimit = tlimitmin;
|
|
|
|
//if track starts far from boundaries increase tlimit!
|
|
if(tlimit < facsafety*presafety)
|
|
tlimit = facsafety*presafety ;
|
|
}
|
|
|
|
if(currentRange < presafety)
|
|
{
|
|
inside = true;
|
|
return tPathLength;
|
|
}
|
|
|
|
// shortcut
|
|
if((tPathLength < tlimit) &&
|
|
(tPathLength < presafety))
|
|
return tPathLength;
|
|
|
|
if(tPathLength > tlimit) tPathLength = tlimit;
|
|
|
|
}
|
|
}
|
|
|
|
// version similar to 7.1 (needed for some experiments)
|
|
else
|
|
{
|
|
if(stepNumber == 1)
|
|
tlimit = geombig;
|
|
|
|
if (stepStatus == fGeomBoundary)
|
|
{
|
|
if (currentRange > lambda0) tlimit = facrange*currentRange;
|
|
else tlimit = facrange*lambda0;
|
|
|
|
if(tlimit < tlimitmin) tlimit = tlimitmin;
|
|
if(tPathLength > tlimit) tPathLength = tlimit;
|
|
}
|
|
}
|
|
|
|
return tPathLength ;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
void G4UrbanMscModel::GeomLimit(const G4Track& track)
|
|
{
|
|
geomlimit = geombig;
|
|
|
|
// no geomlimit for the World volume
|
|
if((track.GetVolume() != 0) &&
|
|
(track.GetVolume() != navigator->GetWorldVolume()))
|
|
{
|
|
const G4double cstep = tPathLength;
|
|
geomlimit = navigator->ComputeStep(
|
|
track.GetStep()->GetPreStepPoint()->GetPosition(),
|
|
track.GetMomentumDirection(),
|
|
cstep,
|
|
presafety);
|
|
// G4cout << "!!!G4UrbanMscModel::GeomLimit presafety= " << presafety
|
|
// << " limit= " << geomlimit << G4endl;
|
|
}
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeGeomPathLength(G4double)
|
|
{
|
|
lambdaeff = lambda0;
|
|
par1 = -1. ;
|
|
par2 = par3 = 0. ;
|
|
|
|
// do the true -> geom transformation
|
|
zPathLength = tPathLength;
|
|
|
|
// z = t for very small tPathLength
|
|
if(tPathLength < tlimitminfix) return zPathLength;
|
|
|
|
// this correction needed to run MSC with eIoni and eBrem inactivated
|
|
// and makes no harm for a normal run
|
|
if(tPathLength > currentRange)
|
|
tPathLength = currentRange ;
|
|
|
|
G4double tau = tPathLength/lambda0 ;
|
|
|
|
if ((tau <= tausmall) || insideskin) {
|
|
zPathLength = tPathLength;
|
|
if(zPathLength > lambda0) zPathLength = lambda0;
|
|
return zPathLength;
|
|
}
|
|
|
|
G4double zmean = tPathLength;
|
|
if (tPathLength < currentRange*dtrl) {
|
|
zmean = lambda0*(1.-exp(-tau));
|
|
if(tau < taulim) zmean = tPathLength*(1.-0.5*tau) ;
|
|
} else if(currentKinEnergy < mass) {
|
|
par1 = 1./currentRange ;
|
|
par2 = 1./(par1*lambda0) ;
|
|
par3 = 1.+par2 ;
|
|
if(tPathLength < currentRange)
|
|
zmean = (1.-exp(par3*log(1.-tPathLength/currentRange)))/(par1*par3) ;
|
|
else
|
|
zmean = 1./(par1*par3) ;
|
|
} else {
|
|
G4double T1 = theManager->GetEnergy(particle,currentRange-tPathLength,couple);
|
|
G4double lambda1 = GetLambda(T1);
|
|
|
|
par1 = (lambda0-lambda1)/(lambda0*tPathLength) ;
|
|
par2 = 1./(par1*lambda0) ;
|
|
par3 = 1.+par2 ;
|
|
zmean = (1.-exp(par3*log(lambda1/lambda0)))/(par1*par3) ;
|
|
}
|
|
|
|
zPathLength = zmean ;
|
|
|
|
// sample z
|
|
if(samplez)
|
|
{
|
|
const G4double ztmax = 0.99, onethird = 1./3. ;
|
|
G4double zt = zmean/tPathLength ;
|
|
|
|
if (tPathLength > stepmin && zt < ztmax)
|
|
{
|
|
G4double u,cz1;
|
|
if(zt >= onethird)
|
|
{
|
|
G4double cz = 0.5*(3.*zt-1.)/(1.-zt) ;
|
|
cz1 = 1.+cz ;
|
|
G4double u0 = cz/cz1 ;
|
|
G4double grej ;
|
|
do {
|
|
u = exp(log(G4UniformRand())/cz1) ;
|
|
grej = exp(cz*log(u/u0))*(1.-u)/(1.-u0) ;
|
|
} while (grej < G4UniformRand()) ;
|
|
}
|
|
else
|
|
{
|
|
cz1 = 1./zt-1.;
|
|
u = 1.-exp(log(G4UniformRand())/cz1) ;
|
|
}
|
|
zPathLength = tPathLength*u ;
|
|
}
|
|
}
|
|
|
|
if(zPathLength > lambda0) zPathLength = lambda0;
|
|
|
|
return zPathLength;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeTrueStepLength(G4double geomStepLength)
|
|
{
|
|
// step defined other than transportation
|
|
if(geomStepLength == zPathLength && tPathLength <= currentRange)
|
|
return tPathLength;
|
|
|
|
// t = z for very small step
|
|
zPathLength = geomStepLength;
|
|
tPathLength = geomStepLength;
|
|
if(geomStepLength < tlimitminfix) return tPathLength;
|
|
|
|
// recalculation
|
|
if((geomStepLength > lambda0*tausmall) && !insideskin)
|
|
{
|
|
if(par1 < 0.)
|
|
tPathLength = -lambda0*log(1.-geomStepLength/lambda0) ;
|
|
else
|
|
{
|
|
if(par1*par3*geomStepLength < 1.)
|
|
tPathLength = (1.-exp(log(1.-par1*par3*geomStepLength)/par3))/par1 ;
|
|
else
|
|
tPathLength = currentRange;
|
|
}
|
|
}
|
|
if(tPathLength < geomStepLength) tPathLength = geomStepLength;
|
|
|
|
return tPathLength;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::ComputeTheta0(G4double trueStepLength,
|
|
G4double KineticEnergy)
|
|
{
|
|
// for all particles take the width of the central part
|
|
// from a parametrization similar to the Highland formula
|
|
// ( Highland formula: Particle Physics Booklet, July 2002, eq. 26.10)
|
|
const G4double c_highland = 13.6*MeV ;
|
|
G4double betacp = sqrt(currentKinEnergy*(currentKinEnergy+2.*mass)*
|
|
KineticEnergy*(KineticEnergy+2.*mass)/
|
|
((currentKinEnergy+mass)*(KineticEnergy+mass)));
|
|
G4double y = trueStepLength/currentRadLength;
|
|
G4double theta0 = c_highland*charge*sqrt(y)/betacp;
|
|
y = log(y);
|
|
theta0 *= sqrt(1.+y*(0.105+0.0035*y));
|
|
|
|
//correction for small Zeff (based on high energy
|
|
// proton scattering data)
|
|
// see G.Shen at al. Phys.Rev.D20(1979) p.1584
|
|
theta0 *= 1.-0.24/(Zeff*(Zeff+1.));
|
|
|
|
return theta0;
|
|
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
std::vector<G4DynamicParticle*>* G4UrbanMscModel::SampleSecondaries(
|
|
const G4MaterialCutsCouple*,
|
|
const G4DynamicParticle* dynParticle,
|
|
G4double truestep,
|
|
G4double safety)
|
|
{
|
|
G4double kineticEnergy = dynParticle->GetKineticEnergy();
|
|
if((kineticEnergy <= 0.0) || (truestep <= tlimitminfix)) return 0;
|
|
|
|
G4double cth = SampleCosineTheta(truestep,kineticEnergy);
|
|
G4double sth = sqrt((1.0 - cth)*(1.0 + cth));
|
|
G4double phi = twopi*G4UniformRand();
|
|
G4double dirx = sth*cos(phi);
|
|
G4double diry = sth*sin(phi);
|
|
|
|
G4ThreeVector oldDirection = dynParticle->GetMomentumDirection();
|
|
G4ThreeVector newDirection(dirx,diry,cth);
|
|
newDirection.rotateUz(oldDirection);
|
|
fParticleChange->ProposeMomentumDirection(newDirection);
|
|
|
|
if (latDisplasment) {
|
|
|
|
G4double r = SampleDisplacement();
|
|
/*
|
|
G4cout << "G4UrbanMscModel::SampleSecondaries: e(MeV)= " << kineticEnergy
|
|
<< " sinTheta= " << sth << " r(mm)= " << r
|
|
<< " trueStep(mm)= " << truestep
|
|
<< " geomStep(mm)= " << zPathLength
|
|
<< G4endl;
|
|
*/
|
|
if(r > 0.)
|
|
{
|
|
G4double latcorr = LatCorrelation();
|
|
if(latcorr > r) latcorr = r;
|
|
|
|
// sample direction of lateral displacement
|
|
// compute it from the lateral correlation
|
|
G4double Phi = 0.;
|
|
if(std::abs(r*sth) < latcorr)
|
|
Phi = twopi*G4UniformRand();
|
|
else
|
|
Phi = phi-std::acos(latcorr/(r*sth));
|
|
if(Phi < 0.) Phi += twopi;
|
|
|
|
dirx = std::cos(Phi);
|
|
diry = std::sin(Phi);
|
|
|
|
G4ThreeVector latDirection(dirx,diry,0.0);
|
|
latDirection.rotateUz(oldDirection);
|
|
|
|
G4ThreeVector Position = *(fParticleChange->GetProposedPosition());
|
|
G4double fac = 0.;
|
|
if(r < safety)
|
|
{
|
|
//normal case, no need to check safety
|
|
fac = 1.;
|
|
}
|
|
else
|
|
{
|
|
// ******* we do not have track info at this level ***********
|
|
// ******* so safety is computed at boundary too ************
|
|
G4double newsafety = safetyHelper->ComputeSafety(Position);
|
|
safety= newsafety;
|
|
if(r < newsafety)
|
|
fac = 1.;
|
|
else
|
|
fac = newsafety/r ;
|
|
}
|
|
|
|
if(fac > 0.)
|
|
{
|
|
// compute new endpoint of the Step
|
|
G4ThreeVector newPosition = Position+fac*r*latDirection;
|
|
|
|
safetyHelper->ReLocateWithinVolume(newPosition);
|
|
|
|
fParticleChange->ProposePosition(newPosition);
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::SampleCosineTheta(G4double trueStepLength,
|
|
G4double KineticEnergy)
|
|
{
|
|
G4double cth = 1. ;
|
|
G4double tau = trueStepLength/lambda0 ;
|
|
|
|
Zeff = couple->GetMaterial()->GetTotNbOfElectPerVolume()/
|
|
couple->GetMaterial()->GetTotNbOfAtomsPerVolume() ;
|
|
|
|
if(insideskin)
|
|
{
|
|
//no scattering, single or plural scattering
|
|
G4double mean = trueStepLength/stepmin ;
|
|
cth = 1.;
|
|
G4int n = G4Poisson(mean);
|
|
if(n > 0)
|
|
{
|
|
G4double tm = KineticEnergy/electron_mass_c2;
|
|
// ascr - screening parameter
|
|
G4double ascr = exp(log(Zeff)/3.)/(137.*sqrt(tm*(tm+2.)));
|
|
G4double ascr1 = 1.+0.5*ascr*ascr;
|
|
G4double bp1=ascr1+1.;
|
|
G4double bm1=ascr1-1.;
|
|
// single scattering from screened Rutherford x-section
|
|
G4double ct,st,phi;
|
|
G4double sx=0.,sy=0.,sz=0.;
|
|
for(G4int i=1; i<=n; i++)
|
|
{
|
|
ct = ascr1-bp1*bm1/(2.*G4UniformRand()+bm1);
|
|
if(ct < -1.) ct = -1.;
|
|
if(ct > 1.) ct = 1.;
|
|
st = sqrt(1.-ct*ct);
|
|
phi = twopi*G4UniformRand();
|
|
sx += st*cos(phi);
|
|
sy += st*sin(phi);
|
|
sz += ct;
|
|
}
|
|
cth = sz/sqrt(sx*sx+sy*sy+sz*sz);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if(trueStepLength >= currentRange*dtrl)
|
|
if(par1*trueStepLength < 1.)
|
|
tau = -par2*log(1.-par1*trueStepLength) ;
|
|
// for the case if ioni/brems are inactivated
|
|
// see the corresponding condition in ComputeGeomPathLength
|
|
else if(1.-KineticEnergy/currentKinEnergy > taulim)
|
|
tau = taubig ;
|
|
|
|
currentTau = tau ;
|
|
lambdaeff = trueStepLength/currentTau;
|
|
currentRadLength = couple->GetMaterial()->GetRadlen();
|
|
|
|
if (tau >= taubig) cth = -1.+2.*G4UniformRand();
|
|
else if (tau >= tausmall)
|
|
{
|
|
G4double b,bx,b1,ebx,eb1;
|
|
G4double prob = 0., qprob = 1. ;
|
|
G4double a = 1., ea = 0., eaa = 1.;
|
|
G4double xmean1 = 1., xmean2 = 0.;
|
|
G4double xsi = 3.;
|
|
|
|
G4double theta0 = ComputeTheta0(trueStepLength,KineticEnergy);
|
|
|
|
if(theta0 > taulim) a = 0.5/(1.-cos(theta0)) ;
|
|
else a = 1.0/(theta0*theta0) ;
|
|
|
|
G4double xmeanth = exp(-tau);
|
|
|
|
G4double c = 3. ;
|
|
G4double c1 = c-1.;
|
|
|
|
G4double x0 = 1.-xsi/a ;
|
|
if(x0 < 0.)
|
|
{
|
|
// 1 model function
|
|
b = exp(tau);
|
|
bx = b-1.;
|
|
b1 = b+1.;
|
|
ebx=exp((c1)*log(bx)) ;
|
|
eb1=exp((c1)*log(b1)) ;
|
|
}
|
|
else
|
|
{
|
|
//empirical tail parameter
|
|
// based some exp. data
|
|
c = 2.40-0.027*exp(2.*log(Zeff)/3.);
|
|
|
|
if(c == 2.) c = 2.+taulim ;
|
|
if(c <= 1.) c = 1.+taulim ;
|
|
c1 = c-1.;
|
|
|
|
ea = exp(-xsi) ;
|
|
eaa = 1.-ea ;
|
|
xmean1 = 1.-(1.-(1.+xsi)*ea)/(eaa*a) ;
|
|
|
|
// from the continuity of the 1st derivative at x=x0
|
|
b = 1.+(c-xsi)/a ;
|
|
|
|
b1 = b+1. ;
|
|
bx = c/a ;
|
|
eb1=exp((c1)*log(b1)) ;
|
|
ebx=exp((c1)*log(bx)) ;
|
|
xmean2 = (x0*eb1+ebx-(eb1*bx-b1*ebx)/(c-2.))/(eb1-ebx) ;
|
|
|
|
G4double f1x0 = a*ea/eaa ;
|
|
G4double f2x0 = c1*eb1*ebx/(eb1-ebx)/exp(c*log(bx)) ;
|
|
|
|
// from continuity at x=x0
|
|
prob = f2x0/(f1x0+f2x0) ;
|
|
|
|
// from xmean = xmeanth
|
|
qprob = (f1x0+f2x0)*xmeanth/(f2x0*xmean1+f1x0*xmean2) ;
|
|
}
|
|
|
|
// sampling of costheta
|
|
if (G4UniformRand() < qprob)
|
|
{
|
|
if (G4UniformRand() < prob)
|
|
cth = 1.+log(ea+G4UniformRand()*eaa)/a ;
|
|
else
|
|
cth = b-b1*bx/exp(log(ebx-G4UniformRand()*(ebx-eb1))/c1) ;
|
|
}
|
|
else
|
|
{
|
|
cth = -1.+2.*G4UniformRand();
|
|
}
|
|
}
|
|
}
|
|
|
|
return cth ;
|
|
}
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::SampleDisplacement()
|
|
{
|
|
const G4double kappa = 2.5;
|
|
const G4double kappapl1 = kappa+1.;
|
|
const G4double kappami1 = kappa-1.;
|
|
G4double rmean = 0.0;
|
|
if ((currentTau >= tausmall) && !insideskin) {
|
|
if (currentTau < taulim) {
|
|
rmean = kappa*currentTau*currentTau*currentTau*
|
|
(1.-kappapl1*currentTau*0.25)/6. ;
|
|
|
|
} else {
|
|
G4double etau = 0.0;
|
|
if (currentTau<taubig) etau = exp(-currentTau);
|
|
rmean = -kappa*currentTau;
|
|
rmean = -exp(rmean)/(kappa*kappami1);
|
|
rmean += currentTau-kappapl1/kappa+kappa*etau/kappami1;
|
|
}
|
|
if (rmean>0.) rmean = 2.*lambdaeff*sqrt(rmean/3.0);
|
|
else rmean = 0.;
|
|
}
|
|
|
|
// protection against z > t ...........................
|
|
if(rmean > 0.) {
|
|
G4double zt = (tPathLength-zPathLength)*(tPathLength+zPathLength);
|
|
if(zt <= 0.)
|
|
rmean = 0.;
|
|
else if(rmean*rmean > zt)
|
|
rmean = sqrt(zt);
|
|
}
|
|
return rmean;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|
|
|
|
G4double G4UrbanMscModel::LatCorrelation()
|
|
{
|
|
const G4double kappa = 2.5;
|
|
const G4double kappami1 = kappa-1.;
|
|
|
|
G4double latcorr = 0.;
|
|
if((currentTau >= tausmall) && !insideskin)
|
|
{
|
|
if(currentTau < taulim)
|
|
latcorr = lambdaeff*kappa*currentTau*currentTau*
|
|
(1.-(kappa+1.)*currentTau/3.)/3.;
|
|
else
|
|
{
|
|
G4double etau = 0.;
|
|
if(currentTau < taubig) etau = exp(-currentTau);
|
|
latcorr = -kappa*currentTau;
|
|
latcorr = exp(latcorr)/kappami1;
|
|
latcorr += 1.-kappa*etau/kappami1 ;
|
|
latcorr *= 2.*lambdaeff/3. ;
|
|
}
|
|
}
|
|
|
|
return latcorr;
|
|
}
|
|
|
|
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
|