Spectral distribution and Coulomb correction for nuclear bremsstrahlung induced by heavy targets

Comparison with experimental data of different theoretical approaches to high-energy electron bremsstrahlung including quantum coherence effects

“…Such an approach was recently validated against accurate experimental data measured for 500 MeV electrons at MAMI in Ref. [24] and using exact partial wave calculations at low energies [49]. The comparison is shown in Fig.…”

“…The integral equation satisfied by the average density matrix is then simplified by using a series expansion up to second order in the small parameter given by the change in the momentum component of the electron, transverse to the photon momentum, in a single scattering process obtaining again a differential equation of the Fokker-Planck type (see Eq. (24) in Ref. [7]).…”

“…( 16), and the functions D 1 and D 2 , see Eqs. (24), need to be evaluated each time the photon energy k is sampled, so that direct use of their definition is very inefficient. Approximate methods for the evaluation of G and Φ were given by Stanev et al [77] employing rational functions, and were widely utilized in essentially all programs written afterwards [27,28,57,75].…”

“…(13), and the functions D 1 and D 2 in Eqs. (24). The dielectric suppression is taken into account with the substitutions presented in Subsection II D 2.…”

“…Bethe and Maximon discovered that such nonradiative corrections can be treated at the leading order of α Z in the high energy limit [23]. Data with systematic uncertainties low enough to validate this conclusion were only recently obtained [24]. The original quantum treatment of the LPM suppression by Migdal [7] did not include the Coulomb correction, which has since been taken into account semi-empirically by expressing his cross section in terms of the radiation length and then adding the Coulomb correction to the latter [18].…”