Search

The upgraded Large Hadron Collider beauty (LHCb) detector will provide data taken in Run3 at the instantaneous luminosity of proton-proton collisions increased to 2⋅1033 cm-2s-1 at energies of up to 14 TeV. To ensure the safe operation of the experiment, a new beam and background Radiation Monitoring System (RMS-R3) was built. RMS-R3 is based on metal-foil detector technology developed at the Institute for Nuclear Research, National Academy of Sciences of Ukraine (Kyiv, Ukraine). The system comprises four detector modules with two sensors in each. Their frequency response is proportional to the flux of incident charged particles. The modules are located around the beam pipe at a distance of 2.2 m from the interaction point. The results measured during the Run3 in 2022 testify to the reliable operation of the system. Applying the asymmetry method, high-accuracy data were obtained on the localization of the interactions region and the beam and background contribution.

A system for quality assessment of micropixel detectors is presented. The system includes a laser scanning microprobe and a setup for studying the response of micro detectors to minimum ionizing particles. The results of the validation of the developed system indicate its suitability for assessing the quality of the latest monolithic active pixel sensors (MAPS), promising elements of large-area tracking systems for future high-energy physics experiments. Comparison of MAPS with the double-sided microstrip detectors of the CBM experiment (FAIR, Darmstadt) indicates the feasibility of the upgrade of its Silicon Tracking System using MAPS.

The processes of excitation and decay of high excited 5He resonances into the d + t channel have been studied in the reaction 7Li(d, α)5He* at the energy of deuteron beam Ed = 37 MeV. In the inclusive spectra of α-particles in addition to the contributions of well known 5He resonances, the high excited states with excitation energies Ex ~ 19 and Ex > 20 MeV were observed. Cluster decay of these resonances was also identified in αd- and αt-coincidence spectra. For the first time, the decay into the d + t channel was observed for 5He resonances with Ex = 22 and 26 MeV. The determined resonance energy and width are partly agreed with the R-matrix analysis of data obtained at the study of d + 3H and n + 4He binary reactions. The possible Coulomb effects in three-particle channels of reaction 7Li(d, α)5He* are also analyzed for different conditions of observation of high excited 5He resonances.

Design of STS and module prototype of silicon micro-strip detector for particle momenta measurements with a resolution of around Δp/p ≈ 1 % are presented. Very high radiation level and inhomogeneous track distribution result in modular construction of the detector stations. The micro-strip detectors are planned to be read out with the help of СВМ-XYTER chip. The system requirements include radiation tolerant sensors with high spatial resolution and a fast readout compatible with high-level-only triggers. Concept of the silicon detection system and the R&D on micro-strip sensors as well as front-end electronics for the building blocks of the detector stations are discussed.

Differential cross-sections of excitation and decay of 7 Li*(7,45 MeV) resonance into 6 Li + n channel in three particle reaction 7 Li(α, α6 Li)n at α-particle energy of 27,2 MeV have been determined in kinematically complete and incomplete experiments. Usage of position sensitive detector made it possible to obtain the data on space distributions of decay events for full range of possible angles and to determine the total probability of this process, which value essentially differs from the data for binary reactions. This result is agreed with previously obtained [1] and confirms the theoretical calculations [2] of decay branching ratio for short lived near-threshold resonances in three particle reactions.

Measurements of differential cross-sections of α-particle inelastic scattering by 7 Li nuclei and 7 Li(α, α6 Li)n, 7 Li(α, αα)t reactions have been performed at the energy Eα = 27,2 MeV. Probability of 7 Li*(7,45 MeV) decay into 6 Li + n channel has been determined from the ratio of cross-sections measured in kinematically complete and incomplete experiments. The large discrepancy of this value (P = 0,49 ± 0,06) and of those obtained at the study of 7 Li*(7,45 MeV) decay in binary reactions can be explained by the influence of Coulomb field of accompanied αparticle on the decay of near-threshold resonances in three-particle reactions.

The processes of formation of stable and unstable states of 3-6He recoil nuclei in the exit channels of reactions 7,6Li(d, 3,4,6He) have been studied in kinematically complete and incomplete experiments at deuteron energy of 37 MeV. The excitation cross-sections of ground and the number of excited states of these nuclei have been determined. The possible mechanisms of continuum formation in inclusive spectra of 3,4,6He nuclei have been also studied. The probability of decay of resonance 5 He*(16,75 МеВ) into d + t channel in reaction 7 Li(d, 4 He)5 He has been determined from the analysis of inclusive and exclusive experiments. Obtained data essentially differs from that obtained at the study of binary reactions.

At deuteron energy of 37 MeV the 6 He inclusive spectra are measured in the exit channel of reaction 7 Li(d,6 He)3 He. The resonance-like structure of spectra in the range of 6 He energies corresponding to the excitation of 3 He recoil nuclei in the range of E* = 6…16 MeV was observed. The experimental data can be described in assumption of existence of 3 He resonances with excitation energies of Е* = 9, 13 and 16 МеV. An analysis of the experimental spectra shows that observed structure of 6 He spectra can be as well explained by the more probable processes of excitation and decay of 7 Li and 7 He unbound states in accompanied reaction channels.

The double-sided silicon microstrip detector prototypes with 50 μm pitch developed together with CiS, Germany, have been characterized in a 2.4 GeV/c proton beam at COSY, Forschungszentrum Jülich, Germany. Data analyses including reconstruction of 1-strip and 2-strip clusters have been performed. We have done the study of charge sharing in the interstrip gap. In particular it was found that there is a charge loss of less than 10 % in the interstrip gap. The calculated signal-to-noise ratio is around 19 for the p-side of the sensor and it is sufficient for hit reconstruction. Also the charge sharing function which allows more precise determination of the hit position in silicon sensor, have been reconstructed.