Vol 60, No 2 (2017)

This investigation carried out variations in the transverse phase-space portrait of an ion beam during a 200-μs pulse of a proton injector in the linear accelerator at the Institute for Nuclear Research. The parameters of the accelerated 400-keV beam at the entrance into the beam transport channel and the beam from the ion source were measured. Numerical simulation of ion-beam acceleration in the proton injector was performed. The noiseless mode of beam generation in the duoplasmatron was obtained. The generator of the duoplasmatron discharge current with a discharge current instability of ±1% or less was developed and put into operation. A compensated resistive-capacitive voltage divider was used in the accelerating tube. The beam emittance measurements showed that the variations in the phase-space portrait of the beam from the upgraded injector during the 200-μs pulse were absent within the measurement accuracy. The normalized emittance for 90% of the beam current was 0.15π × cm × mrad at an ion current of 65 mA.

The RED-100 experimental setup, which is designed to detect elastic coherent neutrino scattering off xenon nuclei, is described. One specific feature of this setup is the possibility of using it in above ground experiments. The setup is based on the RED-100 two-phase emission detector in which liquid xenon is used as a working medium for detection of rare events. The results of the technical run with the setup are presented. These are the evidence of the normal operation of all systems and the readiness of the setup for carrying out an experiment.

An algorithm is proposed that provides reliable discrimination between neutrons and γ rays in mixed fields and reduces the influence of γ-ray pileups at a slight complication of the hardware and the algorithms. The algorithm uses a stepwise Gatti filter for two detection periods (a short period of several hundreds of nanoseconds and a long period of a few microseconds) for the same event. Using mathematical simulation of 12000 neutron and γ-ray events, it has been demonstrated that at particle energies of ~128 keV in the electron equivalent (ee), the algorithm suppresses γ-ray pileups on a level of 10⁴ with a neutron loss of only approximately 1%. Due to the proposed algorithm, the counting ability is of the order of 10⁵ events/s.

The use of soft- and hardware, in particular, the EPICS software environment and the Control System Studio, for building the control system of the “shashlyk” calorimeter in the PANDA experiment is described. The control unit of the Cockcroft–Walton generators, as well as the processing of its data using single-board Raspberry Pi computers, is briefly described.

A multifunctional digital signal converter is described, which is used as a channel for the digital conversion and formatting of radio-interferometric signals with bandwidths of up to 512 MHz. The converter allows changes in its function by only a change in the control program, which is administered by the radio-telescope computer. The multifunctional computer can be used for radiometric and spectral measurements and for tests of the receiving–amplifying equipment of the radio telescope.

The design and research results for a high-power source of ultra-wideband radiation with a nineelement array excited by a bipolar high-voltage pulse with 2-ns duration are presented. The radiation pulses with an effective potential of 1 MV at a pulse repetition rate of 100 Hz were obtained.

The design, circuit, and performance characteristics of the current-regulation unit with a pass transistor bank in a linear mode is described. The unit was designed for building high-speed low-noise precision stabilized-current sources for a low-voltage load, for example, to supply the windings of magnetic systems of charged-particle accelerators. To build the current regulator using the described unit, an external DC power supply is needed. The required value of the output current can be achieved by the parallel connection of a proportionate number of units. For precision output-current regulation, overall current feedback can be applied.

The control system of the neutral beam injector is presented that was designed and constructed at the Budker Institute of Nuclear Physics in Novosibirsk, for the TCV tokamak in Lausanne, Switzerland. The system hardware includes an industrial computer with reconfigurable PCI Express input–output boards, as well as interfacing electronics, which ensures galvanic isolation and electrical compatibility with the injector units. The software and firmware that implement the control system algorithm by means of both the industrial computer and the FPGAs of the reconfigurable boards are written using LabVIEW. The injection parameters are calculated using the beam-power model; the graphical representation and storage of the results are carried out in MATLAB. A communication interface with the tokamak control system is also provided for data exchange and synchronization of operation.

An optical scheme that provides multiple transmission of a probing laser beam through an object under study is considered. A Raman-scattering (RS) spectrometer is described in which this scheme is used to increase a signal in local simultaneous measurements of the temperature and the composition of gaseous mixtures. Broadband RS spectra in gaseous jets in the presence and absence of combustion were obtained as a result of broadband recording. The results of their processing using original software tools are demonstrated.

The specifications and schemes of the main components of the power supplies of the unbalance currents of focusing and defocusing magnets with a series feeding scheme of a nuclotron are presented and the devices are described. The devices were made on the basis of thyristor rectifiers. High operating speed, small ripples, and low noise of the output current are achieved through the use of transistor blocks for the current regulation in a linear mode. The special feature of the described power supplies is the operation of the thyristor rectifiers in the so-called tracking mode that allows to minimise the power losses on the pass transistor bank and to regenerate the energy stored in the inductive elements to the AC network. An additional feedback loop is applied for precision current regulation.

The Shtil-М equipment is described, which is installed on board the Resurs-P spacecraft (SC) and is intended for measuring interferences via the power-supply bus, the voltage between the power-supply circuit and the SC housing, magnetic fields, and also for detecting electrostatic discharges. Maximum attention is drawn to the latter procedure. The module for registering electrostatic discharges is described in detail. A theoretical calculation of the voltage that is induced in the cable during land and full-scale experiments is presented. A technique for conducting land experiments is described and the obtained results are presented. The fact of the registration of an electrostatic discharge on board the Resurs-P spacecraft is confirmed.

The work presents the results of upgrading of microwave spectroradiometer for ground-based remote sensing of Earth’s ozone layer improving essentially the noise temperature (up to value less 1500 K). For this, the low-noise high frequency amplifier was set up in front of the receiver and temperature control of the instrument was changed for stable work of the amplifier.

The design of a gas microflowmeter with the following characteristics is described: the gas flowrate measurement range is ~0–3.0 mg/s; the average sensitivity in this range is 19 V/(mg s^–1); the range of recorded voltages is 25–85 V; and the error is ~2%. It is shown that when a convective heat exchange in calculations of the Reynolds and Nusselt numbers is described, the radius must serve as the characteristic size of a sphere but not its diameter.

Devices that form low-temperature diffuse nanosecond-discharge plasma in a flow of various gases at the atmospheric pressure are described. To form diffuse plasma, negative voltage pulses with an amplitude of several tens of kilovolts and a duration of 5 ns were fed to a point–plane gap in the pulse–periodic mode. By varying the geometry of the discharge gap, the shape of the cathode, and the composition of the working gas, it is possible to obtain plasma with a wide range of parameters and modify the surfaces of various materials with areas of up to several tens of square centimeters.

A resistive dynamic evaporator designed to produce thin films of multicomponent materials is described. The evaporator consists of a hollow vessel 19 mm in diameter and 24 mm high and a conical gate coaxially inserted into the cavity, as well as a wire heating element. When the pressing force of the vapors of the evaporated material begins to exceed the force that presses the gate to the end surface of the vessel, the latter is depressurized; otherwise, it resumes its initial state. Using cadmium telluride as an example, it is shown that these design features provide the formation of high-quality thin films of multicomponent materials.