The physical goals of the ongoing and upcoming measurement series of the LHCb experiment (CERN) concern the properties of matter-antimatter evolution, patterns of lepton flavour universality, and rare decay modes of heavy flavours, among others. To achieve statistical data precision sufficient for observing possible New Physics signals (beyond the Standard Model), a significant increase in instantaneous luminosity is anticipated. The experiment underwent an UPGRADE I (2019-2021) to enable further studies of heavy flavour physics at the Large Hadron Collider (LHC) at energies up to 14 TeV (p-p centre of mass) and instantaneous luminosity up to 2·10^33 cm^-2 s^-1. After the completion of the third and fourth series of physical measurements (RUN 3 2022-2026, RUN 4 2029-2033), a subsequent upgrade (UPGRADE II) will be implemented to ensure the functioning of the experiment's measurement systems in the era of high-luminosity LHC (HL-LHC) during the fifth and sixth series of physical measurements (RUN 5, 6) 2036-2040, 2043-2047) with instantaneous luminosity up to 1.2·10^34 cm^-2 s^-1. The program for this upgrade also includes the possible implementation of a fixed metal microtarget mode.
The dissertation is devoted to developing the concept of a fixed metal microtarget and a method for its implementation in the LHCb experiment. As part of the preparation for the next experiment upgrade (UPGRADE II, 2034-2035), the idea of introducing a fixed metal microtarget mode based on the technology of metal micro-strip detectors, developed at the Institute for Nuclear Research of the National Academy of Sciences of Ukraine, has been advanced.
The feasibility of such an experimental mode is justified in terms of expanding the range of physical goals, which include an original idea of implementing triple nuclear collisions to study matter properties under new conditions of the quantum chromodynamics phase diagram at ultra-high densities and temperatures. A wide assortment of metal targets will provide opportunities for previously unattainable studies of matter evolution patterns depending on individual nuclear properties (deformation, spin and isospin, presence of neutron halo, etc.).
Results of evaluating new possibilities and advantages of physical research in this mode are presented, in comparison and as a complement to the existing program of relativistic heavy nuclei collision studies using the SMOG2 gas target, currently implemented at the LHC only in the LHCb experiment. In particular, for the first-ever proposed search for triple nuclear collisions, an assessment of the dependence of observation conditions for this new physical phenomenon on microtarget thickness in p+C+p and Pb+Pb+Pb reactions is provided. The design of the target system and its expected functional characteristics necessary for microtarget control and stabilization of the interaction frequency between its nuclei and the accelerated LHC beam nuclei are presented. This mode will ensure precise localization of the collision area between target nuclei and the LHC beam.
Various prototypes of the target system functioning in the LHC beam halo under ultra-high vacuum conditions with submicron positioning accuracy are presented. The design of the first target device based on piezoelectric microelectromechanical (MEMS) devices has been developed to study their functional characteristics on test beams at CERN.
The micro-target complex will be managed by the functioning RMS-R3 experimental conditions and safety monitoring system. The functional characteristics of the RMS-R3 system are oriented towards ensuring effective physical measurements in the third data collection series (RUN3, 2022-2026). Fluctuations in the output frequency of detector modules do not exceed 5 Hz at their response frequency of 100 kHz at the nominal luminosity of the experiment in p-p collisions of 2.0*10^33 cm^-2·s^-1. The lower sensitivity limit of RMS-R3 is approximately 10^26 cm^-2·s^-1. The system has a linear response to instantaneous luminosity in the range from 10 to 1.2 MHz. Its data allows tracking the evolution of luminosity, as well as its localization area and their reproducibility. The radiation tolerance of the RMS-R3 system is ensured by its manufacture using the original technology of radiation-resistant metal foil detectors developed at the Institute for Nuclear Research of the National Academy of Sciences of Ukraine.
An original expansion of the RMS-R3 functional capabilities, implemented in the dissertation, is the development and application of the RMS-R3 sensor response asymmetry method for monitoring the stability of the experiment's luminosity area localization and the creation of software in WinCC and MONET environments for real-time display of system data.
