Gabriele Cosmo
223 lines
7.1 KiB
C++
223 lines
7.1 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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// 19.09.21 V. Grichine, first version
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//
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#include "G4GaussXTRadiator.hh"
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#include "G4PhysicalConstants.hh"
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////////////////////////////////////////////////////////////////////////////
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// Constructor, destructor
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G4GaussXTRadiator::G4GaussXTRadiator(
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G4LogicalVolume* anEnvelope, G4double alphaPlate, G4double alphaGas, G4Material* foilMat, G4Material* gasMat,
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G4double a, G4double b, G4int n, const G4String& processName)
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: G4VXTRenergyLoss(anEnvelope, foilMat, gasMat, a, b, n, processName)
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{
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if(verboseLevel > 0)
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G4cout << "Gauss X-ray TR radiator EM process is called"
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<< G4endl;
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fAlphaPlate = alphaPlate;
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fAlphaGas = alphaGas; // 1000; //
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}
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///////////////////////////////////////////////////////////////////////////
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G4GaussXTRadiator::~G4GaussXTRadiator() = default;
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///////////////////////////////////////////////////////////////////////////
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void G4GaussXTRadiator::ProcessDescription(std::ostream& out) const
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{
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out << "Simulation of forward X-ray transition radiation generated by\n"
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"relativistic charged particles crossing the interface between\n"
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"two materials.\n";
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}
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///////////////////////////////////////////////////////////////////////////
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//
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// The Fabian-Strujinsky (FS) algorithm for integration over XTR angle,
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// resolution is about 0.5 mrad
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G4double G4GaussXTRadiator::SpectralXTRdEdxFS(G4double energy)
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{
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G4double result, sum = 0., tmp, cof1, cof2, cofMin, cofPHC, theta2, theta2k;
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G4int k, kMax, kMin;
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cofPHC = 4. * pi * hbarc;
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tmp = (fSigma1 - fSigma2) / cofPHC / energy;
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cof1 = fPlateThick * tmp;
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cof2 = fGasThick * tmp;
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cofMin = energy * (fPlateThick + fGasThick) / fGamma / fGamma;
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cofMin += (fPlateThick * fSigma1 + fGasThick * fSigma2) / energy;
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cofMin /= cofPHC;
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theta2 = cofPHC / (energy * (fPlateThick + fGasThick));
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kMin = G4int(cofMin);
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if(cofMin > kMin)
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kMin++;
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kMax = kMin + 49;
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if(verboseLevel > 2)
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{
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G4cout << cof1 << " " << cof2 << " " << cofMin << G4endl;
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G4cout << "kMin = " << kMin << "; kMax = " << kMax << G4endl;
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}
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for(k = kMin; k <= kMax; ++k)
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{
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tmp = pi * fPlateThick * (k + cof2) / (fPlateThick + fGasThick);
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result = (k - cof1) * (k - cof1) * (k + cof2) * (k + cof2);
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if(k == kMin && kMin == G4int(cofMin))
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{
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sum +=
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0.5 * std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result;
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}
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else
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{
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sum += std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result;
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}
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theta2k = std::sqrt(theta2 * std::abs(k - cofMin));
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if(verboseLevel > 2)
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{
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G4cout << k << " " << theta2k << " "
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<< std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result
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<< " " << sum << G4endl;
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}
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}
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result = 4. * (cof1 + cof2) * (cof1 + cof2) * sum / energy;
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result *= fPlateNumber;
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return result;
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}
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///////////////////////////////////////////////////////////////////////////
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//
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// Approximation for radiator interference factor for the case of
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// Gauss-distributed regular radiator. The plate and gas gap thicknesses are Gauss distributed with RMS
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// sa and sb for plate and gas, respectively.
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// The mean values of the plate and gas gap thicknesses
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// are supposed to be about XTR formation zones.
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G4double G4GaussXTRadiator::GetStackFactor(G4double energy,
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G4double gamma,
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G4double varAngle)
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{
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G4double result, Qa, Qb, Q, Qn, aZa, bZb, aMa, bMb;
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G4double Ma, Mb, Za, Zb;
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G4double sa = fPlateThick/fAlphaPlate;
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G4double sb = fGasThick/fAlphaGas;
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Za = GetPlateFormationZone(energy, gamma, varAngle);
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aZa = fPlateThick / Za ;
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Zb = GetGasFormationZone(energy, gamma, varAngle);
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bZb = fGasThick / Zb ;
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Ma = GetPlateLinearPhotoAbs(energy);
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aMa = fPlateThick * Ma;
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Mb = GetGasLinearPhotoAbs(energy);
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bMb = fGasThick * Mb;
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// Gauss fluctuation of gas gaps according to RMS = sb = b/fAlphaGas
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G4double gre, gim, pre, pim;
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pre = -0.5 * aMa - sa * sa * ( 4./ Za / Za - Ma*Ma )/8.;
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gre = -0.5 * bMb - sb * sb * ( 4./ Zb / Zb - Mb*Mb )/8.;
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pim = sa * sa * Ma/2./Za - aZa;
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gim = sb * sb * Mb/2./Zb - bZb;
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Qa = std::exp(pre);
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Qb = std::exp(gre);
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// Q = Qa * Qb;
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G4complex Ha( Qa * std::cos(pim), Qa * std::sin(pim) );
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G4complex Hb( Qb * std::cos(gim), Qb * std::sin(gim) );
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G4double hre, him, hnre, hnim;
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hre = pre + gre;
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him = pim + gim;
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G4double nn = G4double(fPlateNumber);
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hnre = nn*hre;
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hnim = nn*him;
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Q = std::exp(hre);
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Qn = std::exp(hnre);
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// G4complex H = Ha * Hb;
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G4complex H( Q * std::cos(him), Q * std::sin(him) );
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G4complex Hn( Qn * std::cos(hnim), Qn * std::sin(hnim) );
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// G4complex Hs = conj(H);
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// G4double sigma, D;
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// sigma = aMa * fPlateThick + bMb * fGasThick;
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// D = 1.0 / ((1 - Q) * (1 - Q) + 4 * Q * std::sin(0.5 * (aZa + bZb)) * std::sin(0.5 * (aZa + bZb)));
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// G4complex F1 = ( 1.0 - Ha ) * ( 1.0 - Hb ) * ( 1.0 - Hs ) * G4double(fPlateNumber) * D;
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G4complex F1 = ( 1.0 - Ha ) * ( 1.0 - Hb ) * nn / ( 1. - H );
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// G4complex F2 = ( 1.0 - Ha ) * ( 1.0 - Ha ) * Hb * ( 1.0 - Hs ) * ( 1.0 - Hs ) * (1.0 - std::exp( -0.5 * fPlateNumber * sigma) ) * D * D;
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G4complex F2 = ( 1.0 - Ha ) * ( 1.0 - Ha ) * Hb * ( 1. - Hn ) / ( 1. - H ) / ( 1. - H );
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G4complex R = (F1 + F2) * OneInterfaceXTRdEdx(energy, gamma, varAngle);
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result = 2.0 * std::real(R);
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return result;
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}
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