JINR Research Articles

Status and initial physics performance studies of the MPD experiment at NICA

The Nuclotron-based Ion Collider fAcility (NICA) is under construction at the Joint Institute for Nuclear Research (JINR), with commissioning of the facility expected in late 2022. The Multi-Purpose Detector (MPD) has been designed to operate at NICA and its components are currently in production. The detector is expected to be ready for data taking with the first beams from NICA. This document provides an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input. It also provides a detailed description of the MPD set-up, including its various subsystems as well as its support and computing infrastructures. Selected performance studies for particular physics measurements at MPD are presented and discussed in the context of existing data and theoretical expectations.

Heavy Metal Atmospheric Deposition Study in Azerbaijan Based on Moss Technique and Neutron Activation Analysis

Abstract The results of this investigation show that Azerbaijan industries and agricultural sector provide considerable anthropogenic impact on the environment of Caucasus. The use of moss biomonitoring technique and neutron activation analysis (NAA) is a first attempt to study heavy metal atmospheric deposition in Azerbaijan, a country different relief and climate. The study was undertaken in the summer of 2015 of atmospheric deposition of man-made heavy metal pollutants in the area of mining and processing plant in Gadabay and Dashkasan mininig district. At the same time samples were collected from the Goygol State Reserve in the Lesser Caucasus not far from the city of Ganja. A total 85 moss samples (predominantly Pleurozium schreberi) collected in both environmentally contrast area. Elemental determination was carried out by epithermal neutron activation analysis (ENAA) at the reactor IBR-2 of Joint Institute for Nuclear Research (FLNP JINR). For the first time 44 elemental concentrations were determined (Na, Mg, Al, Si, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Mo, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Tm, Yb, Hf, Ta, W, Au, Th, U). Multivariate statistical analysis of the analytical results obtained will make it possible to identify the main sources of pollution and to assess the role of long-range transport of pollutants.

DGFRS-2—A gas-filled recoil separator for the Dubna Super Heavy Element Factory

The main goal of development of the new Dubna Gas-Filled Recoil Separator (DGFRS-2) is to sufficiently improve the efficiency of studies on heavy and superheavy nuclei at the Super Heavy Element Factory of the Flerov Laboratory of Nuclear Reactions (FLNR) at the Joint Institute for Nuclear Research. The use of beams with the intensity up to 6×1013 s−1 (10 pμA) delivered by the DC280 cyclotron requires an effective setup providing high suppression of background reaction products. The described gas-filled separator is optimized for synthesis and study of heavy isotopes produced in complete fusion reactions of massive nuclei. Basic characteristics of DGFRS-2, as well as the results of the first test experiments, are presented. In comparison to the DGFRS-1, the transmission efficiency was doubled, and the background was reduced by a factor 200.

First nuclear activation experiments using the new accelerator NUCLOTRON in Dubna

Abstract First nuclear activation experiments have been carried out using the new accelerator for relativistic particles NUCLOTRON in Dubna. The distribution of neutrons emitted during the irradiation with 0.65, 1.0 and 1.5 GeV protons from a lead target (∅ = 8 cm, l = 20 cm) and moderated by surrounding paraffin of 6 cm thickness was studied with radiochemical sensors along the beam axis on top of the moderator. Small 139Lasensors of approximately 1 g each were used to measure essentially the thermal neutron fluence at different depths near the surface: i. e. on top of the moderator, in 10 mm deep holes and in 20 mm deep holes, respectively. The reaction 139La (n, γ) 140La (τ1/2 = 40.27 h) was studied using standard procedures of gamma-ray spectrometry and data analysis. The induced activity of 140La increases strongly with the depth of the hole inside the moderator. Its activity distribution along the beam direction on top of the moderator has its maximum about 10 cm downstream the entrance of the protons into the lead and the activity increases about linearily with the proton energy. Some comparisons of the experimental results with model estimations based on the LAHET code are also presented. The experiments were carried out in the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna, Russian Federation.

Neutron Activation Analysis of PM10 for Air Quality of an Industrial Region in the Czech Republic: A Case Study

This work was conducted to focus on pollutant transmission between Poland and Czechia at the most polluted area in the Czech Republic, the Moravian Silesian region. Instrumental neutron activation analysis (INAA) and multivariate statistical analyses were used to determine the mass fractions of inorganic air pollutants accumulated on filters. Particle matters of sizes smaller than 10 µm (PM10) were collected using a high-volume sampler (SAM Hi 30 AUTO WIND). Pollutants PM10 were collected on Whatman QM-A Quartz Microfiber Filters of 150 mm in diameter based on various wind conditions. These filters were irradiated by neutron flux at the experimental reactor IBR-2 at the Joint Institute of Nuclear Research in Dubna, RF. Irradiated samples were measured by gamma spectrometry techniques using HPGe detectors. In total, results are shown for 49 samples (from March to July 2021) and five field blank filters. The mass fractions of 24 elements (Sc, Cr, Fe, Ni, Co, Zn, Se, As, Br, Rb, Mo, Sb, Ba, Cs, La, Ce, Sm, Eu, Tb, Yb, Hf, Au, Th, and U) were determined. The sources of pollution were specified using correlation and exploratory factor analyses and including meteorological conditions. A strong positive correlation was shown between the elements Cr, As, Br, Co, Fe, Sc, Se, Sm, Th, La, and Ce. Elemental exposure to PM10 can be divided based on the factor loadings of common chemical components into three main pollution sources. According to the wind rose, the pollution came from the southeast/west direction; therefore, we can assume that the pollution most likely originated from the metallurgic complex (steel and iron production in the southeast, and a coking plant, metal foundry, and generation plant in the west).

Evaluation of the Efficiency of the Hydrophobic Surface Treatment for Bricks Using Neutron Imaging A. El Abd1* , M. Taman2, S.E. Kiсhanov3, E. Hamad1, К.М. Nazarov3,4 1Reactor physics department, Nuclear research Center, Egyptian Atomic Energy Authority, Egypt 2Department of Structural Engineering, Faculty of Engineering, TantaUniversity,31511,Tanta, Egypt 3Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russia 4Eurasian

Evaluation of the Efficiency of the Hydrophobic Surface Treatment for Bricks Using Neutron Imaging A. El Abd1* , M. Taman2, S.E. Kiсhanov3, E. Hamad1, К.М. Nazarov3,4 1Reactor physics department, Nuclear research Center, Egyptian Atomic Energy Authority, Egypt 2Department of Structural Engineering, Faculty of Engineering, TantaUniversity,31511,Tanta, Egypt 3Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russia 4Eurasian

Research results on development and construction of cyclic electron accelerator MT-22

In this paper we have presented the operation of the cyclic electron accelerator- microtron MT-22 which constructed in cooperation with specialists of Joint Institute for Nuclear Research and Mongolia. We are reached the research level results improving the radiation and technical characteristics of the microtron.

Нейтроны цөмийн харилцан үйлчлэлийн судалгааны хөгжил

Origin and development in Mongolia of the study on interaction of neutrons with nuclei in cooperation with the Joint Institute for Nuclear Research are described. New results оf the statistical model analysis for fast neutron induced (n,p) reaction cross sections arc given.

Design of the Front-End Electronics for Silicon Beam Profilometer Prototype for Light Ions at the BM@N Experiment

Baryonic matter at nuclotron (BM@N) is the fixed-target experiment at the Nuclotron based Ion Collider fAcility (NICA) complex [the Joint Institute for Nuclear Research (JINR), Dubna]. Two beam profilometer planes will be placed inside the beam pipe and used for a beam tuning during the initial stage in the BM@N experiment. According to the physics program of the experiment, beam ions are foreseen from carbon to gold. Due to the wide input charge range, two versions of front-end electronics (FEEs) for the beam profilometer will be used—for light and heavy ions. The article presents the first stage of a beam profilometer development—the design of a prototype for light ions based on a double-sided silicon strip detector and FEE application-specific integrated circuits (ASICs).

The features of heavy metals and metalloids accumulation in the phytomass of the amphipodous moss <i>Pleurozium schreberi</i> (Brid.) Mitt. in the conditions of the Krasnosamarsky Forest area (Samara Region) and the National Park «Buzuluksky Bor» (Orenburg Region)

The paper analyzes ecological and geochemical features of the moss Pleurozium schreberi (Brid.) Mitt., growing in artificial pine plantings of the National Park Buzuluksky Bor (Orenburg Region) and the Krasnosamarsky Forest (Samara Region). The research has been carried out within the framework of the International Program ICP Vegetation (https://icpvegetation.ceh.ac.uk), on the practical use of some bryophyte species in the environmental monitoring of multi-element air pollution in the countries of Western and Eastern Europe and a number of other countries. In the National Park Buzuluksky Bor and the Krasnosamarsky Forest, where species diversity and ecological characteristics of bryophytes have been studied for several years, the phytomass of the moss Pleurozium schreberi has been selected. This species is included in the species list proposed by the organizers of the research work under the UNECE ICP Vegetation Program. A multi-element analysis of Pleurozium schreberi phytomass has been carried out on the basis of the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research in Dubna using instrumental epithermal neutron activation analysis (ENAA). The biogeochemical similarity of the moss Pleurozium schreberi from the Krasnosamarsky Forest and Buzuluksky Bor, estimated by the concentration coefficients, has manifested itself in relation to a large group of heavy metals and metalloids, characterized by a relatively low ability to accumulate in its phytomass (Ti, V, Cr, Fe, Co, As, Se, Rb, Sr, Mo, Cd). Some differences have been revealed in relation to the elements with the maximum accumulation: Cu and Zn in the Krasnosamarsky Forest area, Mn and Ni - in the Buzuluksky Bor. A relatively low content of most of the analyzed heavy metals and metalloids in the soil of the studied territories as well as in the phytomass of the biomonitor moss Pleurozium schreberi allows us to consider them to be background for the steppe zone of the European part of the Russian Federation.

Laboratory demonstration of space gamma-ray spectroscopy experiment with tags of Galactic cosmic rays for testing different types of Martian regolith

The laboratory demonstration of the space experiment was conducted at Joint Institute for Nuclear Research with a new type of planetary gamma-ray spectrometer (GRS-TCP) suite including a gamma-ray detector and a charged particle detector combined in coincidence mode. The proposed GRS prototype can select gamma-ray photons with time tags of charged particles of Galactic cosmic rays (GCR) from a predefined solid angle on the sky. It allows to collect gamma-rays only from a local spot on the irradiated surface under the rover or lander and rejects gamma-ray detections from the surrounding area/spacecraft body significantly improving signal-to-noise ratio. The main objective of this laboratory demonstration was to study the capability of this method to distinguish between local spots with different elemental compositions that could be passed by the rover along its traverse. For this purpose, the soil sample simulants corresponding to the different types of Martian regolith identified by Curiosity rover were created and tested by laboratory measurements. It was experimentally shown that our method of spectroscopy of gamma-rays with tags of charged particles could reliably detect local variations of the planetary regolith.

Digital Twins in the Practice of High-Energy Physics Experiments: A Gas System for the Multipurpose Detector.

The digital twins technology delivers a new degree of freedom into system implementation and maintenance practice. Using this approach, a technological system can be efficiently modeled and simulated. Furthermore, such a twin offline system can be efficiently used to investigate real system issues and improvement opportunities, e.g., improvement of the existing control system or development of a new one. This work describes the development of a control system using the digital twins methodology for a gas system delivering a specific mixture of gases to the time-of-flight (ToF) multipurpose detector (MPD) used during high-energy physics experiments in the Joint Institute for Nuclear Research (Dubna, Russia). The gas system digital twin was built using a test stand and further extended into target full-scale installation planned to be built in the near future. Therefore, conducted simulations are used to validate the existing system and to allow validation of the planned new system. Moreover, the gas system digital twin enables testing of new control opportunities, improving the operation of the target gas system.

The NICA Complex and the MPD experiment at JINR: status and physics potential

The Multi-Purpose Detector is under construction at the Joint Institute for Nuclear Research in Dubna, as part of the NICA Accelerator Complex. The MPD Collaboration aims to study the phase diagram of QCD matter at maximum baryonic density, determine the nature of the phase transition between the deconfined and hadronic matter and search for the critical point. The combination of significant luminosity at NICA, collider geometry of the experiment and collision energies √SNN spanning the range of 4 to 11 GeV, where the transition from baryon to meson dominated matter is expected will allow MPD to provide unique insight into these questions. The status of the assembly of the detector in MPD Hall, as well as the progress in the production of MPD subdetectors will be reported on. The design physics performance of the detector will be discussed with the emphasis on the measurements in the strangeness sector. Tracking and particle identification procedures will enable precise determination of spectra of identified hadrons, including hyperons and hypernuclei, with the possibility of differential measurements and total yield extraction. The quality of directed and elliptic flow determination will be discussed, with comparison to model expectations. The sensitivity of event-by-event fluctuations to the nature of the phase transition and the presence of a critical point will be given. The femtoscopic analysis for charged pions and kaons has shown sensitivity to first order and cross-over phase transitions in EoS seen for the vHLLE model. All those studies will be put in context of addressing outstanding questions on the properties of the region of the QCD phase diagram probed by heavy-ion collisions in the NICA energy range.

Chinese Scientists in Dubna (1956–1965)

The work of Chinese scientists conducted at the Joint Institute for Nuclear Research (JINR) (1956–1965) was inextricably linked to the Sino-Soviet relations in the 1950s–1960s. During the early stage of the JINR, with the aid of advanced equipment and the international cooperation mechanism, Chinese scientists yielded significant results, such as the discovery of the antisigma-minus hyperon and the proof of the law of partial conservation of axial current (PCAC). After the Sino-Soviet split, Chinese scientists’ activities at the institute were hampered by political tensions, eventually resulting in China’s withdrawal from the JINR in 1965. But through the involvement at the JINR, Chinese scientists were trained in scientific practices and participated in international exchange and cooperation which turned them into a new force in China’s nuclear industry, boosting its nuclear weapons, particle physics theory, and accelerator technology. In the meantime, the scientists’ activities extended the international influence of the JINR. The withdrawal of China from the institute impacted both the JINR and the development of science in China.

Cross sections for the Cl35(n,α)P32 reaction in the 3.3–5.3 MeV neutron energy region

Cross sections for the $^{35}\mathrm{Cl}(n,\ensuremath{\alpha})\phantom{\rule{0.16em}{0ex}}^{32}\mathrm{P}$ reaction were systematically measured at incident neutron energies in the range of 3.3 to 5.3 MeV. The experiment was carried out on the Van de Graaff accelerator EG-5 at the Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Russia. Fast neutrons were produced in the reaction $^{2}\mathrm{H}(d,n){\phantom{\rule{0.16em}{0ex}}}^{3}\text{He}$. Alpha particles from the ($n,\ensuremath{\alpha}$) reactions were detected using a gridded ionization chamber (GIC) in which various $^{35}\mathrm{Cl}$ samples (NaCl and ${\text{BaCl}}_{2}$, on a tantalum backing) were placed back to back. The relative and absolute neutron fluxes were measured by two samples of $^{238}\mathrm{U}_{3}\mathrm{O}_{8}$ ($99.999%$) inside the GIC. Data obtained in this measurement were compared with other experimental data of the existing library and theoretical calculations by the talys code. Presented data for the $^{35}\mathrm{Cl}(n,\ensuremath{\alpha})\phantom{\rule{0.16em}{0ex}}^{32}\mathrm{P}$ reaction should help to clarify discrepancies in the various published nuclear data.

Main magnetic focus ion source: Device with high electron current density

We discuss recent experiments performed with an upgraded version of the main magnetic focus ion source (MaMFIS) at the Joint Institute for Nuclear Research in Dubna. The device operates in the range of electron beam energies extended up to 40 keV. The achieved electron current densities are of the order of 10 kA cm−2. This assessment is consistent both with the very short ionization time and with the utmost ionization degree of the produced highly charged ions. Due to its high efficiency, the MaMFIS technology is especially promising for ionization of short-lived radionuclides and heavy elements. A new scheme for charge breeding is proposed.

22nd Workshop on Computer Algebra in Memory of Professor Vladimir Gerdt in Dubna

The 22nd Workshop on Computer Algebra in memory of Professor Vladimir Gerdt was held in Dubna, Russia from May 24-25, 2021. Co-organized by the Dorodnicyn Computing Centre (Federal Research Center "Computer Science and Control") of Russian Academy of Sciences and the Meshcheryakov Laboratory of Information Technologies of the Joint Institute for Nuclear Research, it was devoted to computer algebra and related topics and included a memorial session. The workshop web-site is https://ca2021.jinr.ru.

Применение стека технологий ELK для сбора и анализа системных журналов событий

Modern scientific research in many areas often requires the use of powerful computing systems and complex software systems to effectively solve research problems. Many scientific organizations build their own computing systems, an example of which is the cloud infrastructure of the Joint Institute for Nuclear Research. During the operation of such large computing systems, emergency situations and failures inevitably arise, the resolution of which is primarily based on the analysis of system event logs. As infrastructure grows in scale and complexity, event log analysis becomes a more complex process that requires additional tools to be used for its effective implementation in large-scale infrastructures. In this paper we share our experience in organizing and implementing a system for centralized collection and analysis of system event logs of the JINR cloud infrastructure. We chose the Elasticsearch, Logstash, Kibana (ELK) technology stack as the basis for the developed system, which is widely used to solve similar problems in many other large scientific computing infrastructures and has proven to be suitable both for solving problems of collecting and analyzing event logs of various systems, as well as a number of other problems in semi-structured and unstructured data analysis. On the example of the mechanism for ensuring the fault tolerance of the control nodes of the JINR cloud infrastructure we show that configurations of modern systems can have dynamic nature, complicating examination of system event logs, and how the developed system can be used to simplify their analysis in such situations.

Data Visualization in Cloud Service for Scientific Computations

The saas.jinr.ru service is an attempt to simplify the usage of the JINR Multifunctional Information and Computing Complex (MICC) of the Joint Institute for Nuclear Research (JINR). It aims at providing a simple problem-oriented web-interface to help students and beginner researchers in the physics domain to abstract away the complexity of the computing infrastructure and to focus on the actual research. In this paper we show our approach to one of the problems within the scope of the project: interactive data visualization in a web-browser. When approaching this problem, we considered two major requirements to the system: first, users may not have any programming skills, so any interaction should be performed using simple visual components; second, the system must be horizontally scalable to cope with irregular user work-sessions. The paper describes how we used Bokeh and Dask for integrating our data visualization solution within the Django framework to deal with the first requirement, and the JINR cloud for service scaling. Application of cloud technologies facilitates dynamic distribution of workload across virtual machines, thus making it possible for us to control the balance between efficient hardware utilization and end-user experience. Shared in this work resulting software architecture and applied solutions, as well as some performance considerations, can be used as an example when designing other cloud-native scientific applications.

Laboratory demonstration of space experiment for spectrometry of planetary gamma-rays with tags of Galactic Cosmic Rays producing them

The laboratory demonstration of a space experiment implementing spectrometry of planetary gamma-rays with tags of Galactic Cosmic Rays (GCR) was conducted at Joint Institute for Nuclear Research. The main objective of these efforts was to study the capability of this method to search for heterogeneities in the analog of planetary soil and to compare it with capability of the standard gamma-ray spectroscopy. It was experimentally shown that the method of spectroscopy of gamma-rays with tags demonstrates much higher confidence to search variations of amounts of the most widespread metals, like Al, Fe and Ti, in the planetary regoliths. The numerical simulation of the laboratory experiment shows a very good agreement with observations. It is proved that gamma-ray spectrometry with tags is a perspective method for future space missions to explore the Moon, Mars and another celestial bodies with thin atmosphere or without it.