It becomes difficult and expensive to control TeV-particle trajectories using electromagnets to obtain extracted beams at accelerators. For these purposes, high-gradient devices based on bent crystals are more suitable. These crystals can serve as superstrong lenses with a focal length of less than 1 m with an equivalent magnetic field of 1000 T. In this work, a scheme based on two successive focusing crystals has been implemented to form a 50 GeV axially symmetric beam with a small divergence of 30 μrad in both the horizontal and vertical planes. One of the promising applications of this scheme is the creation of high-energy neutrino beams.

In the TeV energy domain, it becomes difficult and very costly to control the trajectories of particles using electromagnets to obtain the extracted beams on accelerators. Highly gradient devices based on curved crystals are more suitable for these purposes. These crystals can work as super-strong lenses with a focal length of less than 1 m and with an equivalent magnetic field of 1000 T. In this paper, a scheme for the formation of a divergent beam with an energy of 50 GeV by two sequentially arranged focusing crystals is implemented to create an axially symmetric beam with a small divergence of 30 µrad in both horizontal and vertical planes. One promising application of such a scheme is the creation of high-energy neutrino beams.

Research of the ionization loss of 50 GeV protons, the path of which in the depleted layer of the silicon detector was smoothly regulated in the range from 0.3 to 10 mm, is presented. In the experiment, we used a flat silicon detector with a fixed thickness of the depleted layer of 300 μm. The smooth regulation of the path was realized due to the variation of the angle between the surface of the detector and the incident proton beam. The comparison of experimental data and theoretical calculations of the ionization loss demonstrates agreement in all range of thicknesses. Results of the research can be used in order to control the angle between the surface of the detector and the incident beam of relativistic particles. Besides, the results can be used in the analysis of data from astrophysical silicon detectors of charged particles if high-energy particles crossed flat detectors at arbitrary angle.

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.

In view of the successful experience in the generation of pion and kaon secondary beams using a focusing crystal, it has been proposed to build at the U-70 accelerator a new-type channel of secondary particles that does not consume electric power. It has been shown experimentally that an extraction septum magnet can be protected from radiation by applying a multistrip crystal device through current septum shadowing by the crystal that involves the bulk reflection regime for the deflection of particles. The listed applications of crystals are novel in the world practice with accelerators.

A radiation monitor based on a cast polystyrene scintillator with wavelength-shifting optical fibers is described, which has a large aperture; the dimensions of the active part of the detector are 100 × 200 × 5 cm. The monitor also includes a sensor for the presence of a monitored object and a television camera, united by a single control system. The monitor is designed to control transportation of radioactive materials. The operating experience is described.

Various samples of multisectoral high‐pressure high‐temperature (HPHT) single‐crystal diamond plate (IIa type) (4 × 4 × 0.53 mm) are tested for particle detection applications. The samples are investigated by X‐ray diffractometry, photoluminescence spectroscopy, Raman spectroscopy, Fourier‐transform infrared, and visible/ultraviolet (UV) absorption spectroscopy. High crystalline perfection and low impurity concentration (in the {100} growth sector) are observed. To investigate detector parameters, circular 1.0 and 1.5 mm diameter Pt Schottky barrier contacts are created on {111} and {100} growth sectors. On the backside, a Pt contact (3.5 × 3.5 mm) is produced. The {100} growth sector is proved to be a high‐quality detector: the full width at half maximum energy resolution is 0.94% for the 5.489 MeV 226Ra α‐line at an operational bias of +500 V. Therefore, it is concluded that the HPHT material {100} growth sector is used for radiation detector production, whose quality is not worse than the chemical vapor deposition method or specially selected natural diamond detectors.

Surface-barrier structures based on high-purity epitaxial GaAs layers with an ultrahigh-molecular-weight polyethylene converter were tested as fast-neutron detectors. The α-particle spectra and the response to fast neutrons were measured under exposure to a 241Am−Be source. The detectors demonstrated a high neutron-detection efficiency (1.22 × 10−3 counts/neutron) and an acceptable ratio of the signal to γ‑ray background (approximately 40). The possibility of using such detectors at temperatures as high as 120°C was shown.

The results of studies on fast-neutron detectors application of homoepitaxial Me–p––p+ structures are reported. Epitaxial boron doped (NA = (4–8) × 1014 cm–3) layers 65 μm thick were grown on highly boron doped HPHT diamond plates by CVD. The Schottky contact on epitaxial layer with 17 mm2 area was fabricated by 30 nm Pt deposition. The Ti(30 nm)/Pt(30 nm)/Au(50 nm) metallization scheme was used as an ohmic contact on the backside of the p+ HPHT diamond plate. The fast-neutron detection efficiency measured on 241Am–Be source at operational bias of 75 V (the depletion region is 10.6 µm) amounted to 6 × 10–5 puls./neutron.

The generation of beams of secondary particles (π and K mesons) at proton accelerators is a difficult scientific and engineering problem. To obtain narrow directional particle beams for experiments, intense extracted proton beams are used, secondary particles (π and K mesons) are generated at an external target, and they are focused and transferred through long magneto-optical channels. In this work, a surprisingly simple method based on a crystal focusing device has been proposed to obtain secondary beams. An experiment on the production of a secondary beam using a crystal has been performed at the U-70 accelerator. Schemes for the formation of beams with energies E ~ 1 TeV have been proposed for large colliders such as the Large Hadron Collider.

GaAs Schottky barrier detectors for α particle spectrometry have been tested. Detectors had an input window area of 80 mm2 and a working barrier layer thickness of 40–50 μm. The energy resolution (FWHM) measured on 5.499 MeV α line of 238Pu source amounted to 17.5 keV at a generator peak width of 7.8 keV. In the measurements on a 226Ra source, detectors showed linear response and nearly 100% charge collection efficiency at reverse bias above 65 V for all energies of α particles emitted from the source. Tests for thermal stability showed that the proposed detectors can be used in alpha-spectrometry of radionuclides at temperatures up to 120°C.

A radiation source based on the emission of electrons and positrons moving in a short bent crystal has been recently discovered. The emission of particles is due to oscillations of their trajectories near the point of reflections, where trajectories approach a tangent to bent atomic planes. In the experiment performed with the secondary electron beam of the U70 accelerator, it has been shown that the emission intensity can be increased by using a sequence of oriented bent crystals. Passing through six 2.5-mm-long silicon crystals, 7-GeV electrons lose on average 2.0 GeV on emission. This value is several times larger than that in an amorphous medium. Thus, an intense source of radiation has been demonstrated with prospects of application at accelerators.

AbstractGaAs Schottky barrier detectors for α particle spectrometry have been tested. Detectors had an input window area of 80 mm^2 and a working barrier layer thickness of 40–50 μm. The energy resolution (FWHM) measured on 5.499 MeV α line of ^238Pu source amounted to 17.5 keV at a generator peak width of 7.8 keV. In the measurements on a ^226Ra source, detectors showed linear response and nearly 100% charge collection efficiency at reverse bias above 65 V for all energies of α particles emitted from the source. Tests for thermal stability showed that the proposed detectors can be used in alpha-spectrometry of radionuclides at temperatures up to 120°C.