Search

The inclusive differential cross sections for the production of $$\pi^{\pm}$$ and $$k^{-}$$ mesons, protons, and antiprotons with momenta between 6 and 50 GeV/c and nuclear fragments of mass number $$1\leq A\leq 10$$ in the momentum range between 20 and 220 GeV/c were measured in carbon–lead collisions at a beam kinetic energy of 19.6 GeV per nucleon ( $$\sqrt{S_{NN}}=6.3$$ GeV). A comparison with the respective cross sections for carbon–carbon interactions is performed, and the dependence on the target mass number ( $$A$$ ) is estimated. The present analysis shows that the observed particles originate predominantly from peripheral interactions.

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.

The invariant cross sections for forward charged-hadron production at zero angle in carbon–carbon collisions at a beam kinetic energy of 19.6 GeV per nucleon were measured at the U-70 accelerator in an experiment performed with the aid of a combined spectrometer including beam line 22 and detectors of the modified FODS setup. The beam line rigidity was varied between 7 and 70 GeV/ $$c$$ . The results are compared with the predictions of the FTFP model and a self-similar solution for nucleus–nucleus collisions.

We present the results of an experimental study of multiple scattering of positively charged high energy particles in bent samples of monocrystalline silicon. This work confirms the recently discovered effect of a strong reduction in the rms multiple scattering angle of particles channeled in the silicon (111) plane. The effect is observed in the plane orthogonal to the bending plane. We show in detail the influence of angular constraints on the magnitude of the effect. Comparison of the multiple scattering process at different energies indicates a violation of the law of inverse proportionality of the rms angle of channeled particles with energy. By increasing the statistics, we have improved the results of multiple scattering measurements for particles moving, but not channeled, in silicon crystals., arXiv admin note: text overlap with arXiv:1910.00250 minor fixes

From year to year, both morbidity and mortality from malignant neoplasms are growing both in our country and worldwide. Ways to reduce it include early detection of tumors and timely treatment of precancerous diseases to inhibit their malignization. The article describes the contribution of the Department of Oncology of the Kazakh National Medical University in training and improving the knowledge of future oncologists and general practitioners about malignant neoplasms. This serves to increase early detection and treatment efficacy, reduce treatment costs, improve the quality of life of patients and, most importantly, reduce mortality from malignant neoplasms.

Studies on the steering of particle beams using channeling in aligned bent crystals have been performed at IHEP for many years. Different types of extraction schemes with bent crystals and technical equipment have been developed for experiments to test new crystal devices and to study beam collimation processes. A special apparatus has been designed to control the crystal extraction system. In this article, we describe the crystal devices and in-vacuum goniometers, the beam diagnostic tools (intensity and profile measurements), and the beam feedback system.

The results of calculation and theoretical investigation for the creation of a powerful (≈600 MW) pulsed MHD generator on the combustion products from solid (powder) plasma-forming fuel “Start-2” of a new generation are presented. The scheme, methods, results of calculations, and optimization of characteristics of the pulsed MHD generator with the self-excited resistive “iron-free” magnetic system are described. The local, integral, and specific energy and mass-dimensional characteristics are determined. The obtained characteristics are 1.5-2 times higher than those of the first generation MHD generator.

The results of calculation and theoretical investigation for the creation of a powerful (~600 MW) pulsed MHD generator on the combustion products from solid (powder) plasma-forming fuel “Start-2” of a new generation are presented. The scheme, methods, results of calculations, and optimization of characteristics of the pulsed MHD generator with the self-excited resistive “iron-free” magnetic system are described. The local, integral, and specific energy and mass-dimensional characteristics are determined.

The purpose of the work is to review the methods known from the literature and to propose the new methods for preparing the nickel electroplating and nickel electroless plating solutions containing nickel(+2) complexes with 1-hydroxyethane-1,1-diphosphonic acid CH3C(OH)(PO3H2)2 of various proton and stoichiometric composition which allow to obtain high quality nickel coatings. The classification of preparing methods on the basis of chemical reactions nature is given. The advantages and the limitations of each method are discussed. The starting materials are water soluble and water insoluble nickel(+2) salts, nickel(+2) 1-hydroxyethane-1,1-diphosphonates, 1-hydroxyethane-1,1-diphosphonic acid, sodium or potassium 1-hydroxyethane-1,1-diphosphonates. The conclusion is that the methods which base on the use of nickel(+2) bis(1-hydroxyethane-1,1-diphosphonate(1-)) tetrahydrate are the most versatile and convenient. The examples of the preparation of 1-hydroxyethane-1,1-diphosphonate solutions for nickel plating without other substances or with the second ligand (ammonia, ethylenediamine, triethanolamine and others) are given.

The UA9 setup, installed in the Super Proton Synchrotron (SPS) at CERN, was exploited for a proof of principle of the double-crystal scenario, proposed to measure the electric and the magnetic moments of short-lived baryons in a high-energy hadron collider, such as the Large Hadron Collider (LHC). Linear and angular actuators were used to position the crystals and establish the required beam configuration. Timepix detectors and high-sensitivity Beam Loss Monitors were exploited to observe the deflected beams. Linear and angular scans allowed exploring the particle interactions with the two crystals and recording their efficiency. The measured values of the beam trajectories, profiles and of the channeling efficiency agree with the results of a Monte-Carlo simulation., 25 pages, 13 figures

International audience; Experiments to measure the electric and the magnetic moments of short-lived baryons using an internal target and two bent crystals in the vicinity of one of the existing LHC detectors were recently proposed, in the frame of the Physics Beyond Colliders Working Group at CERN. Investigating fixed-target physics in the LHC with in-vacuum solid targets is an unprecedented challenge. As a preparatory step, the layout of the UA9 experiment, installed in the CERN SPS to explore beam manipulations assisted by bent crystals, has been modified to study the feasibility of the double-crystal scenario in a circular accelerator. Ideally, the first crystal should capture halo protons in channeling states directing them onto the internal target to produce rare baryons, whilst the second crystal, located just downstream of the target, should channel the baryons, rotate their polarization vector and deflect them towards the detector area. The upgraded UA9 layout is presented. Preliminary measurements providing an insight of the beam behavior are reported.

Strong reduction of multiple scattering for channeled particles has been observed in an experiment on the deflection of a 180 GeV/c π+-meson beam by bent silicon crystals. The RMS deflections due to multiple scattering for the channeled particles were about six times smaller than for non-channeled ones. It was shown that the approach suggested recently for the description of multiple scattering for channeled particles using the experimental data for random crystal orientations gives fair agreement with the experiment. Keywords: Crystal, Channeling, Multiple scattering, Dechanneling, Beam deflection

A method for designing a pulsed magnetohydrodynamic generator (MHDG) fueled by the combustion products of the modern aluminized plasma-forming Start-2 solid propellant was developed based on experimental and numerical studies of the characteristics and operating modes of the first-generation 500-MW Sakhalin pulsed MHDG fueled by a solid powder propellant (SPP). This paper presents the results of calculation and optimization of the characteristics of the designed pulsed MHDG with a self-excited resistive “iron-free” magnetic system with an electric power of more than 500 MW. The local, integral, and specific energy, weight, and size characteristics of this generator were determined. Stability parameters of supersonic flow during strong magnetohydrodynamic deceleration of the plasma of combustion products and the time of self-excitation of the magnet were determined. The characteristics of the pulsed MHDG were compared with those of MHDGs fueled by the combustion products of the first-generation SPP. It is shown that the obtained energy, mass, and size characteristics of the MHDG fueled by the Start-2 SPP are much superior to those of the pulsed MHDG fueled by the first-generation SPP.

Numerical study has been performed to investigate the operating characteristics and modes of an energy storage device based on a pulsed magnetohydrodynamic generator and a step-up transformer with a stored energy of 25 and 50 MJ and a secondary winding current of 250 kA at the final stage of operation. The operating parameters of such storage devices with rail launchers operating in the mode of rapid-fire launching of several projectiles were calculated.

Lithium dimethylaminomethanediphosphonate(1-) dihydrate (H 3 C) 2 HN+CH(PO 3 H)– 2 Li+·2H 2 O crystallizes from the aqueous solution at room temperature in the orthorhombic system (space group Pca2 1 , a = 9,861(2) A, b = 7,029(1) A, c = 14,946(3) A, z = 4). The crystal structure is determined by single-crystal X-ray diffraction analysis (R1 = 0,0737). The structure is constructed of zwitteranions (H 3 C) 2 HN+CH(PO 3 H)– 2 , cations Li+ and water molecules which are united together by interionic and hydrogen bonds. The zwitteranion is disordered: in the crystal there are two anions with occupancies of 0.5, which are linked together by pseudoplane, with common atom of phosphorus. The lithium cation occupying two positions with occupancies of ~ 0.5 is also disordered. The derivatography method has been used to study dehydration (t init. 110–115 °С, t min DTA 175 °С) and thermal stability (tinit. 240 °C) of the substance in the inert atmosphere. The list of wave numbers of absorption bands maxima in the IR spectrum is given. Solubility of the salt in water, in aqueous solutions of inorganic substances and in some particular organic solvents is evaluated.

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.

The brief review of higher dialkylphosphinic acids applications and of solid metal(+2,+3,+4) dialkylphosphinates is given. The solubility of R2PO2H, R = C7H15, C8H17, in the multiple inorganic and organic solvents media is estimated (0,23 and 0,16 mol/l in 96% ethanol at 23 °C). The methods of crystallizational purification are presented. The results of experimental study of dialkylphosphinic acid decomposition in the reactions with oxidants of different chemical nature (permanganate, dichromate, vanadate, bismuthate, cerium(+4), hexacyanoferrate(+3), diperiodatocuprate(+3), diperiodatoargentate(+3), diperiodatonickelate(+4), sulfuric acid, nitric acid, hydrogen peroxide, peroxydisulfate, hypochlorite, sodium benzenesulfonemonochloramide, bromate, periodate, iodate, manganese dioxide, lead dioxide) in aqueous media are given. Large amount of strong oxidant is required for breaking of both C–P chemical bonds in the molecule of higher dialkylphosphinic acid.

The phase homogeneity of diphenylphosphinic acid (С6H5)2PO2H purified by benzol or aqueous solution recrystallization is proved by X-ray powder diffraction analysis. The thermal behavior of the compound is studied by method of derivatography. The solubility of the compound in the multiple inorganic and organic solvents media is estimated. The results of experimental study of diphenylphosphinic acid decomposition in the reactions with oxidants of different chemical nature (nitric acid, permanganate, dichromate, vanadate, bismuthate, cerium (+4), hexacyanoferrate (+3), hydrogen peroxide, peroxydisulfate, hypochlorite, sodium benzenesulfonemonochloramide, bromate, periodate, iodate, manganese dioxide, lead dioxide) in aqueous media are given. Large amount of strong oxidant is required for breaking of both C–P chemical bonds in the molecule of diphenylphosphinic acid.

Phenomenon of the deflection of charged particle beam due to channeling in a bent crystal is good investigated and successfully applied for extraction of the beam in high-energy accelerators, at the energies of about 10 GeV and higher. However, a significant practical interest presents the problem of deflection and extraction of charged particles with energies below 1 GeV, for example, production of ultrastable beams of low emittance for medical and biological applications. That’s why two novel crystal techniques, namely: thin sequential straight crystal targets, and array of short bent crystal strips were investigated in this report as elements for extraction of the beam from U-70 accelerator. Experimental results were obtained for extraction of 1.3 GeV protons.

The possibility of pure nickel(+2) oxalate NiC2O42H2O precipitation from spent nickel(+2) solutions (electroless plating, electroplating) and spent solution of anodic aluminium oxidation with oxalic acid is shown experimentally. 99,7% of nickel(+2) and 77% of oxalate are recovered. Some physicochemical and chemical properties of nickel oxalate dehydrate (solubility in aqueous solutions with variable concentrations of nitric, sulfuric, hydrochloric, oxalic acids, solubility in organic solvents, reactions with carboxylic, hydroxycarboxylic, aminocarboxylic, aminophosphonic acids, sodium hydroxide, aqua ammonia, amines, aminoalcohols and other nickel(+2) complexing reagents) are studied.

Recently studies are started on the application of volume reflection of particles in crystals for the steering beams (for extraction and collimation of a circulating beam in accelerators). Volume reflection is more efficient than channeling, but requires amplification of the deflection angle by applying multicrystals. The report discusses two new applications of multicrystals made like multistrip structures: (i) the property of effective deflection of particle beam was used to protect the septum magnets of the U-70 in the process of extraction of the proton beam with energy of 50 GeV; (ii) the possibility of generation of gamma radiation was studied in the secondary electron beam with energy of 7 GeV. In both cases, promising preliminary data were obtained.

International audience; At large accelerators, bent crystals are employed to deflect weakly divergent proton beams at the stages of extraction and collimation. We demonstrate that a divergent particle beam may be efficiently deflected using a crystal with a focusing entry face. A 180 GeV/c pion beam with divergence near 0.060 mrad, which exceeds the Lindhard angle by a factor of 4, has been experimentally deflected by 0.25 mrad with efficiency near 22%. The proposed focusing crystal may serve as an element of a novel particle optics for secondary-particle beams in the TeV energy region.

Experimental results on deflection of a 180 GeV/c π+-meson beam by a 23 mm long bent silicon crystal are analyzed to study the dechanneling process of particles due to multiple scattering. A new approach for the determination of contributions from atomic nuclei and electrons to the multiple scattering using the experimental data for random crystal orientations is suggested. The results of simulations performed using this approach, in which the contribution from atomic electrons is considered according to the prescription of Bethe, are in a good agreement with the experiment.

A beam of six-charged carbon ions with an energy of 24.8 GeV/nucleon is extracted from the U-70 synchrotron by means of a silicon crystal bent through 85 mrad. A total of 200000 particles are observed in beamline 4a upon forcing 109 circulating ions to the crystal. The geometrical parameters, timing structure, and composition of the beam have been measured. It has been shown for the first time that, using a bent single crystal, an ion beam with required parameters can be extracted from the accelerator ring and formed for regular use in physics experiments.

The first results of Proton Radiographic Facility operation on the beam with energies of 50–70 GeV extracted from the U-70 synchrotron at the Institute for High Energy Physics are presented. This facility is capable of forming proton radiographic images of samples with an optical thickness as large as 450 g/cm2 and a field of view of 220 mm or more.

Extraction and collimation of the 50-GeV proton beam with a bent silicon crystal at the U-70 accelerator of the Institute for High Energy Physics (Protvino, Russia) was investigated. Until recently, proton beam extraction (and collimation) from accelerators has been effected using crystals with the (111) or (110) plane orientation, when the beam propagates far from the crystal axes. In the described experiment, the silicon crystal was oriented so that the proton beam was incident on it near the 〈110〉 axis. Under these conditions, a part of the beam was deflected by the crystal owing to the dynamic chaos phenomenon. The maximum beam extraction efficiency was as high as ~80%.

It has recently been realized that the focusing of high-energy particle beams at a distance of about 1 cm is promising. A new idea is proposed in this work to focus the beam at a short distance by using a bent plane–parallel silicon plate whose side edges are rotated at a small angle with respect to crystallographic planes. At the U-70 accelerator (IHEP, Protvino), a 50-GeV proton beam has been focused to a narrow line with a width of no more than 30 μm at a distance of 17 cm.

The inclusive differential cross sections for forward production of nuclear fragments at an angle of 0 ∘ in CC collisions at beam energy 20.5 GeV/nucleon ( S N N = 6.3 GeV ) are presented. Measurements have been performed at the U-70 Accelerator Complex (Protvino) using a combined spectrometer on base of the beamline. Fragments selection was carried out by measuring of ionization in scintillation counters taking into account the data from threshold Cherenkov counters and hadron calorimeter. Fragment mass was determined through Cherenkov light emission angle measured in the spectrometer of ring imaging Cherenkov radiation. Data are given for fragments with charge 1 ≤ Z ≤ 6 , atomic number 1 ≤ A ≤ 10 and A / Z 3.4 with momenta from 20 to 210 GeV/c. The measurements are compared with Fritiof model, statistical models and theoretical parameterizations. The discovered differences between theory and experiment are discussed.

Inelastic nuclear interaction probability of 400 GeV/c protons interacting with bent silicon crystals was investigated, in particular for both types of crystals installed at the CERN Large Hadron Collider for beam collimation purposes. In comparison to amorphous scattering interaction, in planar channeling this probability is \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim 36\%$$\end{document}∼36% for the quasi-mosaic type (planes (111)), and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim 27\%$$\end{document}∼27% for the strip type (planes (110)). Moreover, the absolute inelastic nuclear interaction probability in the axial channeling orientation, along the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle 110\rangle $$\end{document}⟨110⟩ axis, was estimated for the first time, finding a value of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.6\%$$\end{document}0.6% for a crystal 2 mm long along the beam direction, with a bending angle of 55 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu $$\end{document}μrad. This value is more than two times lower with respect to the planar channeling orientation of the same crystal, and increases with the vertical angular misalignment. Finally, the correlation between the inelastic nuclear interaction probability in the planar channeling and the silicon crystal curvature is reported.

International audience; Recent discussions about accelerators in high energy physics identified several challenges for the future, where it is necessary to focus particle beams over a distance of a few cm. In this paper, we investigate the focusing of particles by a new crystal device having such a capability. The trajectories of 180 GeV/ c pions passing through a 500 µm thick focusing crystal were reconstructed using silicon microstrip detectors. It is shown that a parallel beam of particles can be focused in one plane at a distance of 15.5 cm from the crystal, in a narrow line with an rms width of 8 µm.

International audience; This paper is devoted to an experimental study of focusing and defocusing positively charged particle beams with the help of specially bent single crystals. Four crystals have been fabricated for this purpose. The studies have been performed at the CERN SPS in 400 GeV/c proton and 180 GeV/c pion beams. The results of measurements of beam envelopes are presented. The rms size of the horizontal profile at the focus was 5–8 times smaller than at the exit of the crystals. The measured focal lengths were 4–21 m. The results of measurements are in good agreement with calculations. Possible applications of focusing crystals in present and future high energy accelerators are discussed.

Background Colorectal cancer (CRC) keeps an upward incidence and rejuvenation trend in Kazakhstan, as well as worldwide, which is the motive for revising traditional risk factors and searching for cause-effective relationships at the genome level. Genetic nature of early-onset CRC is still unclear. The aim of this study was to determine the spectrum of cancer-related gene mutations among early-onset CRC patients. Methods The study included 125 CRC patients aged between 17 and 50 from Kazakhstan. DNAs were extracted from blood using the GeneJET Purification Kit. Next-generation sequencing (NGS) was done on the MiSeq using the TruSightCancer Kit. NGS data were analyzed by the MiSeq Reporter and Variant Studio. SIFT and PolyPhen-2 were used to predict potential pathogenic effects of missense variants on protein structure and function. Results We were able to detect 24 pathogenic/likely pathogenic mutations in 20 (16%) cases, out of which 8 were novel. Out of all mutations, five were detected in the APC gene, three in FANCI, three in BRCA2, two in BRCA1, two in MLH1, and one mutation each, in MSH6, MUTYH, BLM, NBN, ATM, BMPR1A, CHEK2, AIP, and DICER1 genes. The analysis of mutation type has revealed 10 frameshift mutations, 5 missense mutations, 5 stop-gain mutations, 1 in-frame deletion, and 3 mutations involving uncorrected splicing. All mutations were in the heterozygous state. Most of the mutations were not available in the 1000G, ESP6500 and ExAC databases. 5% were available in the dbSNP database, 29.1% in the COSMIC, and 38.4% in the ClinVar and/or LOVD. Pathogenic mutations in high penetrance CRC genes were higher in patients with family history of cancer (FHC) (21.1%, P = 0.0002) and in patients with primary multiple tumors (20.0 %, P = 0.0004) compared with patients without/unknown FHC (3.1%). Conclusions Molecular genetic study of CRC in young patients using NGS allows to identify CRC cases with syndromic and sporadic nature, to stratify the level of risk for a particular patient and his/her relatives, to influence on the diagnostic and therapeutic approaches and clinical examinations. The findings from this study show the diagnostic value of the detected pathogenic mutations in key CRC genes from the Kazakhstan population as promising biomarkers for CRC diagnosis in young people. Legal entity responsible for the study Institute of General Genetics and Cytology. Funding Ministry of Healthcare of the Republic of Kazakhstan. Disclosure All authors have declared no conflicts of interest.

The operation of an electromagnetic multirail launcher of solids powered from a pulsed magnetohydrodynamic (MHD) generator is studied. The plasma flow in the channel of the pulsed MHD generator and the possibility of launching solids in a rapid-fire mode of launcher operation are considered. It is shown that this mode of launcher operation can be implemented by matching the plasma flow dynamics in the channel of the pulsed MHD generator and the launching conditions. It is also shown that powerful pulsed MHD generators can be used as a source of electrical energy for rapid-fire electromagnetic rail launchers operating in a burst mode.

The results of the experimental observation of characteristic X-ray radiation (CXR) excited in solid targets by the extracted and circulated 450 MeV/u C+6 ions beams and circulating 1.3 GeV protons beam are presented. The spectra of X-ray radiation measured from different targets are presented and discussed. It was found that the background radiation near the beams is low enough that allows the observation of the CXR spectral peaks with energies from a few to tens keV by semiconductor X-ray detectors. Applications of the CXR for monitoring of the number of accelerated particles in experimental applied and basic research, including radiobiology and radiation medicine as well as the relativistic nuclear physics and steering of beams by bent crystalline deflectors are proposed.

At large accelerators, bent crystals are employed to deflect weakly divergent proton beams at the stages of extraction and collimation. We demonstrate that a divergent particle beam may be efficiently deflected using a crystal with a focusing edge. A proton beam with divergence near 1 mrad, which exceeds the Lindhard angle by a factor of 30, has been experimentally deflected by 1.8 mrad with efficiency near 15%. The proposed focusing crystal may serve as an element of a novel optical system for secondary-particle beams in the TeV energy region.

This paper presents the results of a numerical study of the operating characteristics and operating modes of an electric power system developed as a multipurpose source of high-current pulses. The system consists of a 50 MW pulsed magnetohydrodynamic (MHD) generator, which utilizes an advanced plasma-generating solid propellant and comprises a liquid-free superconducting magnetic system, and a step-up transformer, whose superconducting windings serve as an inductive energy storage device with a current amplification up to 500 kA in the secondary winding. The parameters of the working fluid and supersonic flow in the MHD channel and the main energy and mass-dimensional characteristics of the pulsed MHD generator weighing about 5 tons were determined. The electromagnetic and mass-dimensional characteristics of the superconducting energy storage transformer were calculated in a model formulation. The results of numerical analysis of the operation of the system in the single and cyclic modes with a resistive external load of 0.01 Ohm are presented. It is shown that with complete switching of the current to the load in 1 ms, a load current of 480 kA and an energy of about 12 MJ are generated. The dimensions and weight of the system (about 15 tons) allow it to be used in mobile electric power plants.

The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70GeV proton beam with carbon, silicon and lead targets were studied to detect decays of charmed \(D^{0}\), \(\bar{D}^{0}\), \(D^{+}\), \(D^{-}\) mesons and \(\Lambda_{c}^{+}\) baryon near their production threshold. Measurements of lifetimes and masses have shown a good agreement with PDG data. The inclusive cross-sections of charm production and their A-dependences have been obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measured cross-section of the total open charm production ( \(\sigma_{\rm tot}(c\bar{c}) = 7.1 \pm 2.3({\rm stat}) \pm 1.4({\rm syst})\) μb/nucleon) at the collision c.m. energy \(\surd s = 11.8\) GeV is well above the QCD model predictions. The contributions of different kinds of charmed particles to the total cross-section of the open charm production in proton-nucleus interactions vary with energy.

The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70 GeV proton beam with C, Si and Pb targets were studied to detect decays of charmed $D^0$, $\overline D^0$, $D^+$, $D^-$ mesons and $\Lambda _c^+$ baryon near their production threshold. Measurements of lifetimes and masses are shown a good agreement with PDG data. The inclusive cross sections of charm production and their A-dependencies were obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measured cross section of the total open charm production ($\sigma _{\mathrm {tot}}(c\overline c)$ = 7.1 $\pm $ 2.3(stat) $\pm $1.4(syst) $\mu $b/nucleon) at the collision c.m. energy $\sqrt {s}$ = 11.8 GeV is well above the QCD model predictions. The contributions of different species of charmed particles to the total cross section of the open charm production in proton-nucleus interactions vary with energy., Comment: 4 pages, 6 pages, 38th International Conference on High Energy Physics 3-10 August 2016, Chicago, USA

International audience; The ordered positions of atoms in crystals give a reason to study multiple Coulomb scattering of high energy charged particles within them. In addition, the accurate representation of multiple scattering of high energy protons in a bent crystal is important for studies of crystal assisted collimation at the SPS and the LHC. Multiple scattering of 400 GeV/c protons in bent silicon crystals was measured for orientations far from the directions of main crystallographic planes and axes in conditions excluding channeling of protons. The observed RMS widths of the angular distributions are a little larger than those obtained from the Moliere theory. Simulation of multiple scattering in a model of binary collisions with the crystal atoms shows about 3.5% decrease of the RMS deflection with respect to the model of a sequence of random collisions. We consider this as a possible indication of a reduction of multiple scattering of protons in a crystal in comparison with its amorphous state.

The effect of multiple volume reflections in one crystal was observed in each of several bent silicon strips for 400 GeV/c protons. This considerably increased the particle deflections. Some particles were also deflected due to channeling in one of the subsequent strips. As a result, the incident beam was strongly spread because of opposite directions of the deflections. A modified multi-strip deflector produced by periodic grooves on the surface of a thick silicon plate was used for these measurements. This technique provides perfect mutual alignment between crystal strips. Such multi-strip deflector may be effective for collider beam halo collimation and a study is planned at the CERN SPS circulating beam.

Channeling is the confinement of the trajectory of a charged particle in a crystalline solid. Positively charged particles channeled between crystal planes oscillate with a certain oscillation length , which depends on particle energy. A crystal whose thickness is half the oscillation length for planar channeling may act as a mirror for charged particles. If the incident angle of the particle trajectory with the crystal plane is less than the critical angle for channeling, under-barrier particles undergo half an oscillation and exit the crystal with the reversal of their transverse momentum, i.e., the particles are “mirrored” by the crystal planes. Unlike the traditional scheme relying on millimeter-long curved crystals, particle mirroring enables beam steering in high-energy accelerators via interactions with micrometer-thin straight crystal. The main advantage of mirroring is the interaction with a minimal amount of material along the beam, thereby decreasing unwanted incoherent nuclear interactions. The effectiveness of the mirror effect for ultrarelativistic positive particles has been experimentally proven at external lines of CERN-SPS. The mirroring effect in a 26.5-μm-thick Si crystal has been studied in the experiment with a narrow beam of 400 GeV/ c protons at the CERN-SPS. The reflection efficiency for a quasi-parallel beam is larger than 80%.

A radiographic facility, placed in the initial rectilinear part of the injection channel, which is intended for transporting a proton beam from U-70 into an accelerator-storage complex, is described. It is designed for energy 50 GeV with field of view 60 mm and makes it possible to obtain an image of objects with optical thickness to 400 g/cm2 with resolution 100 μm. The first static and dynamic experiments performed in our country at 50 GeV have shown the advantages of pulsed radiography in studying fast processes in ultradense media.

It has been recently proposed using a bent crystal with a declining curvature instead of a uniformly bent crystal in order to improve extraction and collimation of the circulating beam in the accelerator. Variable curvature crystal devices developed to implement this idea are described. Curvature values measured along the crystal plate are presented. It is shown that focusing of high energy beams can also be focused using the developed devices.