Development of High Granular Neutron Time-of-Flight Detector for the BM@N experiment

The HGND (High Granular Neutron Detector) is developed for the BM@N (Baryonic Matter at Nuclotron) experiment on the extracted beam of the Nuclotron at JINR, Dubna. The HGND will be used to measure the azimuthal flow of neutrons produced with energies ranging from 300 to 4000 MeV in heavy-ion collisions at beam energies of 2--4 AGeV. The azimuthal flow of charged particles will be measured using the BM@N magnet spectrometer. The data on the azimuthal flow of neutrons will shed light on the study of the high-density Equation of State (EoS) of isospin-symmetric nuclear matter, which is crucial for studying astrophysical phenomena such as neutron stars and their mergers. The HGND has a highly granular structure with approximately 2000 plastic scintillation detectors (cells), each measuring 4$\times$4$\times$2.5 cm$^3$. These detectors are arranged in 16 layers, with 121 detectors in each layer, and are subdivided by copper absorber plates with a thickness of 3 cm. The light from each cell is detected with SiPM (Silicon Photomultiplier) with an active area of 6$\times$6 mm$^2$. Developed multi-channel TDC board based on the Kintex FPGA chip with a bin width of 100 ps will be used to perform precise timestamp and amplitude measurement using Time-over-Threshold (ToT) method. Good spatial resolution due to the high granularity together with a cell's time resolution of 100-150 ps ensures neutron reconstruction with good energy resolution. The design of the detector as well as the results from test measurements and simulations have been presented

The production of a machine designed for the cold radial cyclic forging of solid and tube billets

This paper gives an account of a new project for the design and production of a radial cyclic forging machine. This new design considers the advantages of its predecessor and of modern trends within the engineering industry. The use of this machine could enable the considerable reduction of production wastes. Besides the cold cyclic technology implemented in this machine, it will also allow for the increase in energy efficiency, for the minimum capital investments. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

Performance of ALICE AD modules in the CERN PS test beam

Two modules of the AD detector have been studied with the test beam at the T10 facility at CERN. The AD detector is made of scintillator pads read out by wave-length shifters (WLS) coupled to clean fibres that carry the produced light to photo-multiplier tubes (PMTs). In ALICE the AD is used to trigger and study the physics of diffractive and ultra-peripheral collisions as well as for a variety of technical tasks like beam-gas background monitoring or as a luminometer. The position dependence of the modules' efficiency has been measured and the effect of hits on the WLS or PMTs has been evaluated. The charge deposited by pions and protons has been measured at different momenta of the test beam. The time resolution is determined as a function of the deposited charge. These results are important ingredients to better understand the AD detector, to benchmark the corresponding simulations, and very importantly they served as a baseline for a similar device, the Forward Diffractive Detector (FDD), being currently built and that will be in operation in ALICE during the LHC Runs 3 and 4.Peer reviewe

Рассолы глубоких горизонтов кимберлитовой трубки Удачная

The study was focused on groundwaters sampled from boreholes drilled to deep horizons of the Udachnaya kimberlite pipe and the host sedimentary strata. Brines in the rocks significantly complicate underground mining. Analysis of the hydrogeological setting is required to ensure safety during mining to the design levels. The features of chemical composition and the geochemical evolution of brines in the crust can be clarified in a more detail on the basis of new reliable data on strong chloride saline solutions that formed in complex geological and tectonic conditions. Kimberlite and water samples were taken from the ore bodies and host sedimentary strata at the depth of 680–980 m. Conventional methods of quantitative and instrumental analysis were applied to study the chemical composition of brines. Mineral composition of kimberlite was determined by powder diffractography and X-ray fluorescence methods. Geological, structural and tectonophysical methods were used to reveal and describe the tectonic structure of the kimberlite pipe area. Groundwaters with salinity of 280–406 g/L are strong and very strong calcium chloride brines. The chlorine-bromine ratio has a small range of 48–57; the sodium-chlorine ratio varies from 0.11 to 0.18. According to their geochemical features, the studied groundwaters are metamorphosed brines that have analogues across the Siberian platform. Physical and chemical processes were simulated to investigate the degrees of saturation of strong brines relative to the minerals of water-bearing rocks. The simulation results show that the brines in the Western ore body of the Udachnaya pipe are strongly undersaturated in the deep horizons in comparison to carbonate, sulfate and chloride minerals. This suggests possible dilution of brines during their geochemical evolution. A detailed study of the tectonic structure identified structural elements that control the distribution and migration of groundwaters in the rocks. In the mining sites, brines occur mainly in the fault zones, fault junctions and intersections with the contacts of kimberlite bodies. Integration of hydrogeological and geostructural data can provide a basis for prediction and assessment of the sites with increased water inflow in the deep horizons involved in mining.В работе представлены результаты изучения подземных вод, вскрытых скважинами в глубоких горизонтах кимберлитовой трубки Удачная и вмещающих осадочных толщах. Рассолы, обводняя горный массив, существенно осложняют проходку подземных горных выработок. Анализ гидрогеологической обстановки позволит обеспечить безопасную разработку месторождения до проектных отметок. Получение новых достоверных сведений о формировании крепких рассолов хлоридного состава в сложных геолого-тектонических условиях даст возможность объяснить многие особенности химического состава и геохимической эволюции рассолов в земной коре. Глубина отбора образцов кимберлитов и проб воды из рудных тел и вмещающих отложений составила 680–980 м. Химический состав рассолов проанализирован количественными традиционными и инструментальными методами, минеральный состав кимберлита определен методом порошковой дифрактографии и рентгенофлуоресцентным способом, тектоническое строение участка кимберлитовой трубки охарактеризовано с помощью геолого-структурных и тектонофизических методических приемов. Подземные воды с минерализацией 280–406 г/дм3 представляют собой крепкие и весьма крепкие рассолы хлоридного кальциевого состава. Величина хлорбромного отношения имеет небольшой диапазон (48–57), натрий-хлорный коэффициент изменяется от 0.11 до 0.18. Геохимические особенности изученных подземных вод позволяют отнести их к метаморфизованным рассолам, имеющим аналоги на всей Сибирской платформе. Физико-химическое моделирование степени насыщения крепких рассолов относительно минералов водовмещающих пород позволило установить, что рассолы западного рудного тела трубки Удачная в глубоких горизонтах по отношению к карбонатным, сульфатным и хлоридным минералам резко недонасыщены, что свидетельствует о возможном разбавлении рассолов в ходе их геохимической эволюции. Детальное изучение тектонического строения месторождения позволило выявить структурные элементы, контролирующие распределение и миграцию подземных вод в горном массиве. Основные проявления рассолов в горных выработках приурочены к зонам разрывных нарушений, их узлам и участкам пересечения с контактами кимберлитовых тел. Комплексирование гидрогеологических и геолого-структурных данных может служить основой для прогнозной оценки участков повышенных водопритоков в глубоких горизонтах, вовлекаемых в эксплуатацию

Long- and short-range correlations and their event-scale dependence in high-multiplicity pp collisions at 1as = 13 TeV

Two-particle angular correlations are measured in high-multiplicity proton-proton collisions at s = 13 TeV by the ALICE Collaboration. The yields of particle pairs at short-( 06\u3b7 3c 0) and long-range (1.6 < | 06\u3b7| < 1.8) in pseudorapidity are extracted on the near-side ( 06\u3c6 3c 0). They are reported as a function of transverse momentum (pT) in the range 1 < pT< 4 GeV/c. Furthermore, the event-scale dependence is studied for the first time by requiring the presence of high-pT leading particles or jets for varying pT thresholds. The results demonstrate that the long-range \u201cridge\u201d yield, possibly related to the collective behavior of the system, is present in events with high-pT processes as well. The magnitudes of the short- and long-range yields are found to grow with the event scale. The results are compared to EPOS LHC and PYTHIA 8 calculations, with and without string-shoving interactions. It is found that while both models describe the qualitative trends in the data, calculations from EPOS LHC show a better quantitative agreement for the pT dependency, while overestimating the event-scale dependency. [Figure not available: see fulltext.

Global baryon number conservation encoded in net-proton fluctuations measured in Pb–Pb collisions at √sNN = 2.76 TeV

Experimental results are presented on event-by-event net-proton fluctuation measurements in Pb–Pb collisions at √SNN=2.76 TeV, recorded by the ALICE detector at the CERN LHC. These measurements have as their ultimate goal an experimental test of Lattice QCD (LQCD) predictions on second and higher order cumulants of net-baryon distributions to search for critical behavior near the QCD phase boundary. Before confronting them with LQCD predictions, account has to be taken of correlations stemming from baryon number conservation as well as fluctuations of participating nucleons. Both effects influence the experimental measurements and are usually not considered in theoretical calculations. For the first time, it is shown that event-by-event baryon number conservation leads to subtle long-range correlations arising from very early interactions in the collisions.publishedVersio

Evidence of Spin-Orbital Angular Momentum Interactions in Relativistic Heavy-Ion Collisions

The first evidence of spin alignment of vector mesons (K^{*0} and ϕ) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element ρ_{00} is measured at midrapidity (|y|<0.5) in Pb-Pb collisions at a center-of-mass energy (sqrt[s_{NN}]) of 2.76 TeV with the ALICE detector. ρ_{00} values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum (p_{T}<2  GeV/c) for K^{*0} and ϕ at a level of 3σ and 2σ, respectively. No significant spin alignment is observed for the K_{S}^{0} meson (spin=0) in Pb-Pb collisions and for the vector mesons in pp collisions. The measured spin alignment is unexpectedly large but qualitatively consistent with the expectation from models which attribute it to a polarization of quarks in the presence of angular momentum in heavy-ion collisions and a subsequent hadronization by the process of recombination