Main scientific results by INP BSU staff in 2016 in the area of fundamental scientific research
- A new type of meta-atoms – hollow carbon microspheres – was developed, described in theory and implemented in experiment. 2D-structures (meta-surfaces) were manufactured based on these meta-atoms. Precise control of the geometry and dielectric properties of carbon skeleton facilitates emergence of meta-atoms with a given electromagnetic response, and the design of certain spatial distribution of elements in 2D-structure leads to creation of meta-surfaces, which are characterized by near-ideal absorption of electromagnetic radiation, or surfaces with tunable gradient of refractive index in frequency range from GHz to THz.
- The temperature dependence of infrared absorption spectra by thin films made of single-walled carbon nanotubes was experimentally shown and explained in theory by temperature dependence of conductivity of doped semiconductor nanotubes. A method of distinguishing of contributions from intrazone and interzone electron transition to infrared absorption spectrum was proposed. This method is based on measurements of absorption spectra at various temperatures or various doping degrees of single-walled nanotubes.
- A method of measurement of previously unavailable to measure magnetic moments of short-lived charmed and strange hyperons was proposed. The method uses the effect of spin rotation of such particles in bended crystals at energies of Large hadron collider (LHC) and proposed circular collider (FCC).
- An effect of oscillations in angular distributions of positively and negatively charged particles with high energy was predicted for transition through bended crystals. Based on numerical simulation optimal conditions for observation of predicted effect were determined and experiments were proposed.
- Calibration of energy of hadron jets was found, the cross-sections for jet formation were measured and maximum possible parameters of deviations from Standard model were determined in events with gwo jets in final state of proton-proton collisions in ATLAS experiment at energy 8 and 13 TeV.
- Principal suitability of transient processes to be used as the moment of time when high energy particles start to interact with inorganic crystal detector material was found.
Main scientific results by INP BSU staff in 2015 in the area of fundamental scientific research
- An effect of increase of intensity of hard gamma-radiation from electrons in bended and modulated crystals was predicted and observed in experiment. The effect is caused by capture of electrons in channeling mode because of incoherent scattering on nuclei and bound electrons in crystal. This effect can be used in development and optimisation of sources of hard gamma-radiation to study the properties and modify atomic nuclei, and for radiation action on matter.
- The intensity of quasi-Cherenkov and Cherenkov radiation of a charged particle, which moves in a photonic crystal (a periodic structure formed by parallel metallic threads), was shown to sharply increase in the range of radiation wavelengths of the order of magnitude equal to the dimensions of scatterer.
- Crucial limitations of the use of heterogenous detector modules in high-luminosity collider experiments were determined. Principal possibility of use of materials of garnet structure type based on yttrium was shown for creation of electromagnetic calorimeters, which are insensitive to radiation for LHC with high luminosity.
- Excessive radiation degradation of hadron calorimeter of CMS detector (Large hadron collider) was explained. An economically effective method of improvement of radiation insensitivity was proposed, that is suitable for the complete operation term at increased luminosity of the collider.
- Differential cross-section of 3-jet events was measured at energy 7 TeV in the centre of mass system of protons using detector ATLAS at Large hadron collider (LHC), differential cross-section of the Drell-Young process was measured at energy 8 TeV in the centre of mass system of protons using detector CMS at LHC. LePeProGen event generator was updated for simulation of Drell-Yan process. Monte-Carlo generator was developed for simulation of exclusive birth of electron pairs in electon-proton scattering as a background process during the birth of "hard" photons. The contribution of hard photon radiation during the measurement of charge asymmetry was estimated in lepton-proton scattering in ultrarelativistic approximation. A new approach to solution of the problem of divergences in quantum field theory, transition of gravity from low energies to high energies, dark energy problems was proposed in the framework of minimum description length theory.
- Strong absorption and the opportunity of tuning in wide ranges of radiation interaction with superthin graphene films was shown in experiment and in theory. The ways to increase the absorption of inherent electromagnetic radiation in microwave range were proposed in graphene monolayers up to 100% using the selection of optimal thickness and dielectric parameters of the bed, optimal angle of incidence and polarization of inherent wave. CVD quality of graphene (grain size, presence of holes and on the contrary, germs of second and third layers) was shown to have low effect on the electromagnetic properties of sandwich structures polimer/graphene that have optimal design (i. e. that provides absorption of 50% electromagnetic wave that transverses orthogonally to the surface in free space). An operation principle was formulated and a scheme of effective polarizer of electromagnetic radiation in wide range of spectrum using this effect was proposed.
Main scientific results by INP BSU staff in 2014 in the area of fundamental scientific research
- Models of explosion-magnetic generators were developed and tested. They implement direct conversion of chemical energy of explosion into electric and are capable of producing high current electron beams with the current up to 30 kiloAmperes. Graphite cathodes for microwave generator with large area (63 cm2 and 132 cm2) were designed and studied in experiment. Electron beams with current higher than 20 kiloAmperes were produced with these cathodes. Portable devices for distant control of wideband pulse generators were developed and manufactured. These control devices contain optical transmitter and receiver and a synchronisation block for them.
- A method of synthesis of sandwich graphene/polymer type structures on dielectric bed with the number of layers up to 4 was developed. A number of experimental models was manufactured. Experimental studies of electromagnetic response of these structures in microwave range (26-37 GHz) were performed. Graphene/polymer structure was found to provide EM shielding at the level of 75% (50% absorption of the power of microwave signal and 25% reflection) for waveguide variant of experiment. Theoretical explanation of observed electromagnetic effects was given. The result was published in the Nature, Sci. Reports group of journals. Several innovation contracts with Russian organisations was signed to continue the development of these works.
- Increase of de-channeling length of electrons was predicted and discovered at MAMI microtron of University of Mainz, Germany. The effect is caused by the capture of electrons in the body of the crystal.
- Degradation of cylinder part of electromagnetic calorimeter of CMS collaboration was estimated for the period up to 2018. The limits of use of decreasing of the temperature for reduction of noise from photodetectors in detector cells were suggested.
- Limitations and advantages of various scintillation materials for front calorimeters of experimental systems on high luminosity colliders were studied.
- Principal suitability of lead tungstate crystal growth on open type setups from iridium needles was shown. Hence these scintillator crystals can be produced for use in high energy physics.
- New types of fast photodetectors solid state photomultipliers were studied. CdTe semiconductor detectors with high atomic number were studied.
- Characteristics of hyperfine interaction between «nitrogen-vacancy» color center (NV center) and 13С atom closest to the vacancy on the NV center axis in diamond were calculated using DFT method. It was shown that the spectrum of optically detectable resonance for such system has a typical shape and consists of three pairs of lines, split in zero magnetic field with the value 187,4 kHz typical for this system.
Main scientific results by INP BSU staff in 2013 in the area of fundamental scientific research
- During study of interaction of electromagnetic radiation with composite materials, which are based on multi-walled carbon nanotubes experimental data on microwave and terahertz parameters of composite matter were systemized and a theory was developed for them. Three regimes of interaction of nanotubes with electromagnetic radiation were singled out: quasistatic, dynamic and intermediate. It was shown in theory, that the screening effect for longitudinal field in multi-walled nanotubes in quasistatic regime greatly reduces their electromagnetic response and essentially impacts the effective parameters of composite materials.
- Experimental mock-up of microwave pulse generator with virtual cathode was manufactured (axial vircator) with power supply from explosion-magnetic generator. Experimental mock-ups of explosion-magnetic generator were developed, manufactured and tested. Tests of experimental mock-up of microwave generator with power supply, which uses either direct conversion of chemical energy of explosion into electric energy or from accumulators. Maximum power of microwave generation, in experiments reached 300 MW.
- Effect of manyfold increase of radiation intensity of gamma-quanta from diverging beam of high-energy electrons was predicted and discovered at SPS accelerator ()CERN) during multiple volume scattering in a single crystal.
- Essential contribution into the development and planning of technical proposals on modernisation of end cap parts of electromagnetic calorimeter of CMS collaboration experimental setup (CERN) was made for work of LHC with increased luminosity. Preparing of technical sketch documentation on experimental setup of PANDA collaboration (GSI,FAIR, Darmstadt) was finished.