A novel slow extraction system for the U-70 synchrotron of the IHEP (Protvino) is presented. The system has been routinely employed since 2013 to extract carbon-nuclei beams with an intermediate energy (455 MeV/nucleon) for applied fixed-target radiobiological research. Issues of the beam dynamics and engineering implementation of the system are considered. The results of experimental beam observations in the U-70 machine are presented, which prove the adequacy of the design approach.

The results obtained by estimating the contribution of 8Be and 9B nuclei to the coherent dissociation of 10 C, 10 B, and 12 C relativistic nuclei in nuclear track emulsions (“white” stars) are presented. The selection of white stars accompanied by 9B leads to a distinct peak appearing in the distribution of the excitation energy of 2α2 p ensembles and having a maximum at 4.1 ± 0.3 MeV. A 8Be nucleus manifests itself in the coherent-dissociation reaction 10 B → 2 He + H with a probability of (25 ± 5)%, (14 ± 3)% of it being due to 9B decays. The ratio of the branching fractions of the 9 B + n and 9 Be + p mirror channels is estimated at 6 ± 1. An analysis of the relativistic dissociation of 12 C nuclei in a nuclear track emulsion revealed nine 3α events corresponding to the Hoyle state.

A magneto-optical scheme of a proton microscope based on an active U-70 accelerator radiography complex is presented. The microscope is created in the magnetic structure of the radiography complex only by changing strengths of quadrupole lenses without changing their position. The achieved magnification ratio of the image of the studied object is no smaller than 10 at E = 60 GeV. This is sufficient for a spatial resolution of images of 10–20 μm.

We describe a technique for attaining extended transversally-flat paraxial dose fields with the intermediateenergy carbon beam slowly extracted at the magnetic-field flat-bottom from the IHEP U-70 synchrotron. To this end, a fixed-radius circular beam sweep with the aid of a compact electromechanical wobbler with rotating permanent dipole magnets is applied. A technique for tuning the beam transfer line and the irradiation facility proper at the interim radiobiological workbench with an external fixed target is substantiated. A brief description of its engineering implementation is presented. Results of the successful experimental verification of the technique in question with a carbon nuclear beam from the U-70 machine are reported, in particular, results of the primary radiobiological exercises accomplished in cooperation with the scientists at the MRRC of the Russian Ministry of Healthcare.