On the transition radiation and bremsstrahlung from a relativistic electron with a nonequilibrium field

Spectral-angular distributions of relativistic electrons' radiation in a thin layer of matter

“…In this case practically all the radiation of a particle hits in the collimator and, actually, we deal with a spectral density of radiation (13). This effect is similar to the suppression effect of bremsstrahlung spectral density in a thin layer of matter, which was pointed at in works [2,3]. For spectral density of radiation, however, it is characteristic that the linear growth of emission intensity with the target thickness increasing is replaced by logarithmic growth.…”

“…1 the dependence of spectral-angular density of radiation from a polar angle of radiation θ at various values of the parameter 2 β is represented. The indicated curves show, that at 1 2 < β the angular distribution of radiation has a maximum in the direction of the initial velocity of a particle and decreases rapidly with the growth of the radiation angle θ (see (13)).…”

“…A case of large coherence length as compared with a target thickness is the one of particular interest. It was shown in [1][2][3] that in this case an effect analogous to the Landau-Pomeranchuk-Migdal effect is possible. An experimental investigation of this effect has been recently realized on the SLAC accelerator [4,5].…”

The influence of non-parallelism of electron and positron velocities upon high-energy e+e− pair ionization loss in thin plate

“…Moreover in [14] it was shown that in this situation along with the Chudakov effect of pair ionization loss reduction the opposite effect (however not very large) may take place, which consists in exceeding by pair ionization loss of the sum of separate electron and positron losses in the plate.…”

“…Let us also note that the problem statement considered in [11] and [14] probably better corresponds to the experimental situation of the first accelerator-based investigation of pair ionization loss [9,10] in which the pairs loss was measured in thin silicon detector situated on different distances from golden foils in which the pairs were created by high-energy photons. Taking into account the contribution from transition radiation leads to somewhat better description of the obtained here results than the one provided by theories of pair ionization loss in boundless medium [1][2][3][4][5].…”