The bremsstrahlung of accelerated electrons passing through a converter is used to study multiparticle photonuclear reactions. The results of calculations, numerical modeling, design, and testing of a special magnetic cleaning system to obtain a “pure” beam of bremsstrahlung quanta when studying the cross-sections of such reactions at the LUE-40 linac are presented. The system is based on commercially available permanent magnets of rectangular cross-sections. The maximum on-axis field is 0.9 T, which provides sufficient separation of the electron beam and gamma rays at a distance of more than 90 mm from the magnet.

Experiments to determine the yields and bremsstrahlung flux-averaged cross-sections σ(Еγmax) of photonuclear reactions on the natural Mo targets were performed on the beam from the electron linear accelerator LUE-40 with the use of the γ-activation technique. The bremsstrahlung end-point energies were in the range Еγmax = 35…80 MeV. The bremsstrahlung quantum flux was calculated with the program GEANT4.9.2 and, in addition, was monitored using the 100Мо(γ, n)99Мо reaction. Calculations of the yields and average cross-sections σ(Еγmax) for photonuclear reactions on stable Mo isotopes were computed using the σ(Е) cross-sections from the TALYS1.95 code (for the level density model LD1). A comparison of experimental and calculated cross-sections σ(Еγmax) for reactions 92Мо(γ, 2n)90Мо and 92Мо(γ, pn)90Nb was performed.

Acceleration of intense short-pulsed electron beams in transient mode with energy spread about a few tenths of a percent is the actual problem for RF linacs, in an instance, for an electron injector of a storage ring. In this work we study both analytically and numerically unsteady self-consistent beam dynamics in the one section RF linac fed from SLED. For compensation of the transient beam loading, resulting in beam energy spread, a method of a beam delay with respect to RF pulse is consider. In order to increase efficiency of this method we choose a homogenous dick-loaded waveguide with π/2 phase advance as an accelerating structure that characterized by the minimal frequency dispersion of group velocity. The preliminary results show that the full beam loading compensation is possible for the 1.2 A beam at its acceleration up to 60 MeV during 50 ns.

The results of self-consistent beam dynamics simulation are presented for the linac of the NESTOR storage ring. Consideration is given to the influence of particle energy change at the output of the electron gun during the current pulse. The obtained data have formed the basis for the computation of the beam transport line for research in the field of high energy physics.