Non-contact electrical methods are widely used for research and control of semiconductor wafers. The methods are usually based on surface potential measurement (CPD) in combination with illumination and/or deposition of charges on the sample using a corona discharge, and are also based on the measurement of surface photo-emf. By photo-EMF (SPV) it is possible to determine the lifetime of minor charge carriers, their diffusion length and detect traces of heavy metals on the surface. In addition, using photo-EMF it is possible to determine the surface resistance of the plate, some parameters of the dielectric layer on the surface and barrier photo-EMF (JPV). Electrical performance results reflect the influence of near-surface characteristics on the final performance of devices. The aim of the work was to develop a universal digital probe electrometer that implements various non-contact electrical methods for analyzing semiconductor wafers, in which the change in operating modes and configuration, transmission of the received data, remote testing and calibration are carried out via digital local control channels. This paper describes a universal digital probe electrometer developed by the authors, which implements the above-described non-contact electrical methods for analyzing semiconductor wafers (CPD, SPV and JPV), in which the change in operating modes and configuration, transmission of the received data, remote testing and calibration are carried out via digital local control channels. Due to their high speed, electrical characterization methods are suitable for inspecting semiconductor wafers during production. The results of testing the developed probe electrometer in CPD, SPV and JPV modes are presented, which reflect the effectiveness of the proposed approaches.

Metrological support creation and use of heat transfer etalons are important stages in the development of modern materials science. This is especially concerned to the emergence of new materials in the world with previously unattainable thermophysical parameters. The purpose of this work was to develop and experimentally verify the idea of joint application of the transient gratings method which is well-known in nonlinear optics and the single thermal diffusivity etalon of conventional type for the heat transfer metrological control in materials of a wide values range. The method proposed is based on thermal diffusivity etalon application as a source of calibrated optical signals that are excited in it by short laser pulses. Their lifetime is formed by the etalon thermal diffusivity and on the transient grating spatial period. The etalon linear graph of gratings lifetimes as a function of the gratings periods squared and grating lifetime of the material under study are used for the thermal diffusivity calculation. Thermal diffusivity of thin sub-surface layers of the samples under study – duraluminium, monocrystalline silicon and thermoelectric lead telluride film was measured. The results obtained are in close agreement with the reference values.

Sources of pulsed photon radiation are widely used in science and industry. In this regard, there is a growing demand for dosimetry instruments capable of operating in these pulsed photon radiation fields. Until now there is no comprehensive methodology that describes the characteristics of reference fields of pulsed photon radiation required for calibration and verification of dosimetry equipment. The aim of this paper was to study the possibility of using a medical linear electron accelerator as a generating source of a reference pulsed photon radiation field. The paper investigates main characteristics of photon radiation field (namely, spectrum and average energy) generated by CLINAC in two modes of operation: 6 MV and 18 MV. Additionally it researches the possibility of attenuation of the CLINAC photon radiation intensity by a lead filter. The spectrum and average energy of the CLINAC photon radiation were calculated by means of Monte Carlo simulation in the Fluka program. The validation of the calculation was determined by comparing the attenuation coefficients calculated by the model with ones obtained experimentally by using real CLINACs. Experimentally, the attenuation coefficients were obtained by measuring the air kerma rate generated by the photon radiation fields of Varian VitalBeam and Varian iX CLINACs at a given point of space. Based on the simulation results, the Ḣ*(10) ambient dose equivalent ratio generated by CLINACs were calculated. It was found that the lead filter effectively attenuates the CLINAC photon radiation in terms of both air kerma rate and ambient dose equivalent rate to levels suitable for calibration of dosimetry equipment designed to measure pulsed radiation. It is shown that the lead filter significantly affects both the photon spectrum of the CLINAC and its average energy.

Increasing the reliability of control of cast iron structure and its physical and mechanical characteristics is an important scientific and technical task of the machine-building industry. The paper studies the possibilities of controlling the structure of cast irons using structural noise created by ultrasonic scattering on graphite inclusions of different shapes. The subject of the present studies was such characteristics of structural noise as amplitude-temporal A(t) and as root mean square value of the amplitude of the ultrasonic waves backscattering field AN, compared with the data on ultrasonic velocity and strength or tensile strength of cast iron samples. As a result of the studies, a significant difference between the amplitude parameters of the AN structural noise obtained for samples with different shapes of graphite inclusions at 5 MHz was revealed for the first time. So, for example, for samples of gray cast iron (Russian: СЧ10, СЧ15, СЧ20, СЧ25), having predominantly plate-like form of graphite inclusions, the value of AN on 14–15 dB exceeds that measured in high-strength specimens of the cast iron with the prevailing form of spherical graphite inclusions ВЧ50 (Russian), etc. At the same time growth of longitudinal ultrasonic velocity amounted to 20–25 %. The method of rejection of gray cast iron from high-strength cast iron according to the data of amplitude parameters of structural noise AN at unilateral and local sounding of the object without using an additional reference signal reflected from its oppositional wall is suggested.

The dispersion control of micro- and nanoparticles by their images is of great importance for ensuring the specified properties of the particles themselves and materials based on them. The aim of this article was to consider the possibilities of using the Hough transform for dispersion control of overlapping particles and their agglomerates. Analysis of the application of the Hough transform for overlapping particles and their agglomerates showed the following. The particularities of the conventional implementation lead to the preferred registration of large particles, the shift of the centers of overlapping particles, and the distortion of the size values. To use the Hough transform correctly, fine-tuning of all its parameters is required. To automate this process, the dependences of the number and size of particles recorded in the image on the parameters of the Hough transform was investigated. The studies were carried out on test images with a known number and size of particles. The results showed that when the threshold parameters of the Hough transform change, the number of detected particles stabilizes near their optimal values. When the size range of particles detected by the Hough transform changes, the histogram of the particle size distribution changes. In this case, the optimal width of the range is determined by the most stable extremes of the histogram. The maximum center-to-center distance is set at least half of the optimal range. The configuration algorithm is described and implemented. It implies repeatedly running the Hough transform with different combinations of parameters. The algorithm includes stages of coarse and fine-tuning, which allows to getting closer to the optimal parameters. The efficiency of the algorithm has been confirmed on test and real images. Tests have shown that the errors in determining the size and number of particles of the multi-pass Hough transform are on the same level or exceed these indicators for analog methods.

Modern tools of water supply systems monitoring at enterprises or in the housing sector use laser liquid sensing systems. In this case, as a rule, laboratory analyses of the obtained liquid samples are used, as well as spectral analysis methods when scanning the liquid with light for different wavelengths. These approaches do not allow for real-time analysis of a moving fluid flow (flow analysis). The paper considers a version for constructing of a system for online detecting and identifying emergency clots of pollutants in a liquid stream using laser radiation. The basic principles of the system construction, the block diagram of the system structure and parameters for identification of clots of substances under study flowing in the pipelines of the sewage or water treatment system at industrial enterprises are given. When constructing the system, several wavelengths of laser radiation are used, simultaneously directed to the one point of the studied clot of the studied fluid flow. Light wavelengths are determined at the stage of preparation for the study. At this initial stage of the process, optical transmission spectra of substances that are a priori possible in the studied fluid flow are analyzed. The main criterion for wavelengths choose is difference in substances optical transmission spectra at the se selected wavelengths. For the possibility of technical separation of signals at different wavelengths of the emitting radiation, the radiation fluxes are modulated. Creation of standards for identification substances in fluid flow clusters is carried out in the form of lattice functions containing the components of the substance optical transmission spectrum at certain wavelengths of laser radiation. Modulation of radiation is proposed to be carried out by controlling the pumping of each emitters of the system. The proposed system will find application in the oil and gas, processing industry, water filtration and purification systems, industrial enterprises and agricultural processing enterprises.

Quantitative analysis of the structure of metals and alloys is an important part of modern metal science. To obtain quantitative data and build dependencies, metallographic image processing programs are used, oriented both for scientific research and for use in industry. Programs capable of automatically performing metallographic analysis are of great interest to consumers. When advertising such programs, it is often claimed that they allow quantitative analysis of the structure with virtually no time. The purpose of this work was to determine the time spent on quantitative metallographic analysis in some image processing programs presented on the Belarusian market. Connected and unconnected metallographic objects were considered. It is shown that automatic quantitative analysis is possible for unconnected objects (powders, cast iron graphite). The time required is within a minute. For connected objects (structures of metals and alloys after metallographic etching), the time required to detect objects and obtain digital data is 10–40 min or more, depending on the complexity of the object, which is unacceptable for factory laboratories that analyze a large number of samples per shift. Therefore, it is recommended that potential users of metallographic image processing software always require a substantive demonstration of the automatic measurement capabilities of the proposed software.