Instruments and Experimental Techniques

The results of the simulation of the spectrometer acceptance for forward production of hadrons and nuclear fragments in nucleus−nucleus collisions at the U-70 accelerator complex are presented. The spectrometer is composed of beamline 22 of the U-70 accelerator and the detectors of the upgraded FODS facility with location of nuclear targets at the beamline head. The calculations have been performed in the virtual Monte Carlo environment of the ROOT package from the GEANT4 toolkit (version 4.10.02.p02). The passage of secondary hadrons (charged π and K mesons, protons, and antiprotons), secondary light nuclei (D, T), and heavier isotopes (He, Li, Be, B, and C) have been studied. In addition to the acceptance for each type of particles and nuclei, the coefficients of their escape from an ensemble due to decays and interactions during their passage through the spectrometer have been calculated.

A review of the two generations of front-end electronics for the muon spectrometer of the ALICE experiment at the Large Hadron Collider is presented. The basic elements of the front-end electronics are application-specific integrated circuits that are used in 1.1 × 10⁶ measuring channels and devices for communication with the data-acquisition system. The first generation of the electronics operates in the trigger mode and is characterized by an input throughput of 3 × 10³ events/s at an output data rate of 3.2 Gbit/s. The second generation is designed to operate under conditions of a high luminosity of the collider at input count rates of up to 10⁵ events/s. Signal processing is performed in the continuous readout mode. The communication devices with the data-acquisition system use application-specific chips that provide optical communication with a data transfer rate of 0.8 Tbit/s.

Recently, SoCs (System on a Chip) are the serious competitors and even more efficient systems than CPUs and other data processing systems based on FPGA and computer. Also, the Multi-Channel Analyzer (MCA) is one of the main components of the nuclear electronics system that determines many of the radiation measurement parameters. A prototype of the proposed new generation of MCA systems, based on SoCs, is presented which is very small, compact, and at the same time, has the full functionality of a data acquisition board. It also has many features for analyzing output data and making changes to the overall system structure through software. The designed board uses ZYNQ to provide substrate and main infrastructure to add more peripherals for any specific application. The proposed system is in fact a multi-purpose system that can simultaneously provide the functionalities of an oscilloscope, computer-independent spectrum demonstration, and even any desired application for inaccessible radiation fields thanks to its low cost, lightness and compact size. In addition, the designed analogue section in this system, besides the digital section, facilitates making the system more compact and flexible in order to fully customize, match and remove some conversional analogue parts.

A model and a laboratory method were developed for determining the major systematic errors affecting time interval measurement (TIM) accuracy. The laboratory method investigates the optimum trigger level for the high slew rate timing pulses that achieves the highest TIM accuracy. The overall errors due to the measurement setup and the trigger level, at which the measurements are executed, are the most considerable sources of systematic errors. Previously these error sources were modeled. In this study the model was modified for estimating more precisely the systematic errors contributed by the measurement setup. Also a laboratory method was experienced to determine the optimum trigger level for the timing pulses. Applying these methods achieve a TIM accuracy in the picosecond range.

An experimental facility designed for separating lithium isotopes in plasma using the ion cyclotron resonance (ICR) method is described. High values of the lithium-isotope separation factor (α > 50) are attainable at the facility. A lithium-plasma source, the layout of cyclotron ion heating, and a collector system for lithium enriched and depleted with the ⁶Li isotope are described in detail. The methods used for measuring the parameters of the lithium plasma and the separation characteristics of the facility are also presented. The use of a “shadow,” i.e., a strip from the enriched-lithium collector without the lithium deposit on the depleted-lithium collector, for diagnostics of the plasma column rotation is noted. The projects for ICR facilities developed with our participation for separating isotopes of other chemical elements are briefly reported.

A scanning interferometric method for studying inhomogeneous deformations of thin plates of dielectric crystals under the action of a homogeneous electric field (converse flexoelectric effect) is proposed. The results of using this method to determine the type and magnitude of inhomogeneous deformations (spherical and cylindrical bending deformations) with an accuracy of up to 10 nm in model perovskite ferroelectric single crystals and related materials are demonstrated.

The use of dynamic magnonic crystals created by a surface acoustic wave (SAW) for measuring the parameters of a surface magnetostatic wave in a film of yttrium iron garnet (YIG) on a gallium gadolinium garnet (GGG) substrate is described. A method for measuring the dispersion characteristics of a surface magnetostatic spin wave (SMSW) and results of such measurements are presented. The method is based on measuring reflected SMSWs at frequencies of forbidden magnonic gaps using the same antenna for the excitation of incident SMSWs and the detection of reflected SMSWs. The attenuation parameter of the SMSW is determined by measuring the frequency width of reflected SMSW signals. The dispersion curves have been measured for several angles between the direction of the magnetic field and the wave vector in the plane of YIG film and for two thicknesses of the YIG film at wave numbers ranging up to 1000 cm^–1. Results of measurements of the attenuation parameter are also presented.

The work is dedicated to solving the problem of miniaturization of plasma instruments, in particular, the development of a miniature ion analyzer for small spacecraft. The described instrument can be used as part of a prognostic and diagnostic complex designed to monitor the conditions in the solar wind and detect critical events. The target parameters of the instrument include the ability to separate protons and α particles in the energy range of 500–10 000 eV with an energy resolution ΔE/E not worse than 10%. The flight unit should comply with the 1U form factor of the CubeSat standard.

The fields of the calibration dipole magnet were corrected on the magnetic measurements bench of the INP SB RAS using active and passive corrections, as a result of which, the magnetic field uniformity was improved from 1 × 10^–4 to the level of 1 × 10^–5.

The model of a dual-slider actuation method is established and two prototypes of the motor are constructed for experimental verification. The dual-slider linear motor consists of two mass blocks which are bonded by a piezoelectric element, a base and a plastic plate. The two mass blocks and the piezoelectric element serve as a slider. By changing the frictional forces of each contact surface of the motor, the slider can be driven in different directions based on the principle of impact drive mechanism, of which maximum velocities are 2.63 mm/s and –1.02 mm/s when driven at the same duty ratio of 90%. The moving range of the slider is 33 mm and the positioning precision is 40 nm. It has been verified that the experimental results are consistent with the theoretical results.