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"Micromegas detectors production sites at the DLNP"
A. Gongadze
At the present time two sites for the production of the Micromegas detectors are created at the DLNP. The first site was intended for production and tests of the Micromegas chambers of the New Small Wheels (NSW) of the Muon Spectrometer of the ATLAS experiment. There were produces and tested 70 two-sided readout panels, each has 3 m2 area, and 33 Micromegas chambers (quadruplets). By mid of April the full set of 33 quadruplets will be transported to the CERN and team will move to CERN to participate in the wheel's assembly and commissioning. The second site is intended for the full cycle production of the Micromegas detectors of 60 cm wide according to the corresponding R&D project.
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"Current status of development and operation of a suite of IBR-2 cryogenic moderators in 2012-2020"
K.A. Mukhin
In 2012, tests of CM-202 (first stage of the suite of IBR-2 cryogenic moderators) began in the trial operation mode at power. The CM-202 in the cryogenic mode for physics experiments has operated for more than 4500 h. During this time, data on the change in the viscosity of the moderator material under irradiation and empirical quantitative values of released radiolytic hydrogen were obtained, the cryogenic cooling system of the suite was upgraded, and neutron-physical data for cryogenic moderators (CM) were collected during their operation in different temperature modes.
In December 2020, in the trial operation mode, the CM-201 central direction moderator (beamlines 1, 4, 5, 6, 9) operated in the cryogenic regime for physics experiments for the first time.
The report will provide a brief overview of the operation of the suite of IBR-2 cryogenic moderators from 2012 to 2021. The evaluation of the efficiency and reliability of technological equipment of the CM suite in various operation modes is given. Comparative characteristics of the viscosity, hydrogen yield, and temperature modes of operation of CM-201 and CM-202 are presented, taking into account their different geometry of the working chambers and different location of the cryogenic chambers relative to the reactor core. Basing on the results of the work for this period, spectra of the neutron flux of the beams in the thermal and cold modes, plans for the development of the CM suite, the structure of the commissioning group, number of personnel and necessary resources for putting the CM suite into operation will be presented.
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"Biomonitoring studies in the Moscow region"
Vergel K.N.
The results of biomonitoring of atmospheric deposition of heavy metals in the Moscow region, carried out in the framework of the UNECE ICP Vegetation program are presented in the report. The current study is already the third one on the territory of the Moscow region, which allows to evaluate temporal and spatial changes in the content of heavy metals in mosses. Application of graphic and statistical methods of analysis to the results obtained made it possible to identify anthropogenic and plant components, as well as the component of the earth's crust as sources of accumulation of chemical elements in mosses. In addition, the main sources of entry of elements into the air have been identified. For the study area, indicators have been calculated to evaluate the level of pollution of the study area. The visualization of the distribution of elements in the study area became possible thanks to the use of modern GIS technologies.
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Meeting agenda
- Kinetics of irreversible processes in partially disordered structures. Tropin T.V. (based on the materials of the doctoral dissertation. Specialty 01.04.07 - Condensed matter physics)
"Kinetics of irreversible processes in partially ordered structures"
Tropin T.V. (FLNP JINR)
The results of research and descriptions of two characteristic processes, relevant for the advanced condensed matter physics: glass-transition and aggregation of nanoparticles are presented. Experimental research of solutions of fullerenes of various polarity with a set of complementary methods was performed, which allowed to investigate both the structure of the formed clusters and the kinetics of their increase, a number of other phenomena. A theoretical description of kinetic processes in fullerene solutions is presented. Furtherly, description of the polystyrene glass-transition kinetics in a wide range of cooling and heating rates q is discussed. A general theoretical research of the glass-transition of model system in a wide range of velocities q was performed, dependences of the main characteristics of the current process on temperature and pressure variation rates were studied. Finally, glass-transition and the features of the structural organization of nanoparticles in thin films of polymer fullerene-polystyrene nanocomposites are studied using the reflectometry method. (According to the materials of the doctoral dissertation. Specialty 01.04.07 - Condensed matter physics).
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"Measurements of WH and ZH production in the H→b anti-b decay channel in pp collisions at 13 TeV with the ATLAS detector"
(on results obtained by the JINR team at the ATLAS at the LHC)
F. Ahmadov
Measurements of the Standard Model Higgs boson decaying into a b anti-b pair and produced in association with a W or Z boson decaying into leptons, using proton-proton collision data collected between 2015 and 2018 by the ATLAS detector, will be presented. The measurements use collisions produced by the Large Hadron Collider at a centre-of-mass energy of √s=13 TeV, corresponding to an integrated luminosity of 139 1/fb. The production of a Higgs boson in association with a W or Z boson is established with observed (expected) significances of 4.0 (4.1) and 5.3 (5.1) standard deviations, respectively. Cross-sections of associated production of a Higgs boson decaying into bottom quark pairs with an electroweak gauge boson, W or Z, decaying into leptons are measured as a function of the gauge boson transverse momentum in kinematic fiducial volumes. The cross-section measurements are all consistent with the Standard Model expectations, and the total uncertainties vary from 30% in the high gauge boson transverse momentum regions to 85% in the low regions. Limits are subsequently set on the parameters of an effective Lagrangian sensitive to modifications of the WH and ZH processes as well as the Higgs boson decay into b anti-b.