RESEARCH OF EARLY STAGES OF MODELING

In represented article the questions of estimate of accuracy of an average integral characteristics of random process in the course of imitation modeling is considered. For the purposes of analytical treatment of initial stage of modeling a conditionally nonstationary Gaussian process is analyzed as stationary Gaussian process with boundary prehistory. A model of approximant autocorrelation function is recommended. Analytical expression for variance and mathematical expectation of average integral estimation are obtained. Statistical estimation efficiency criterion, the probability of belonging to correct parameter interval is introduced. Dependences of closeness in estimation statistics clearing interval at transient behavior are researched for various types of processes

Study of the intake system of automotive tractor internal combustion engines with variable parameters

Increasing the effective performance of automotive tractor engines is primarily associated with the intensification of the working process parameters. One of the options for solving this problem is to improve the cylinder filling parameters, which will allow to increase the engine power and torque. In addition to mechanical and gas turbine supercharging, the little-studied resonant supercharging of the engine is of interest. In this case, by selecting the parameters of the inlet path of the engine, it is possible to achieve a significant increase in pressure in the zone of the inlet valve opening without expenditure of useful energy, using only the kinetic energy of the gases of the inlet path. The paper proposes a method to calculate the geometric parameters of the intake tract using a one-dimensional model of gas flow. The results obtained from the numerical investigations give good convergence. The article can be useful for masters, graduate students, and engineering and technical workers involved in the design of internal combustion engines

Reconstruction of interfaces of periodic multilayers from X-ray reflectivity using a free-form approach

Grazing-incidence X-ray reflectivity (GIXRR) is a widely used analysis method for thin films and multilayer structures. However, conventional so-called model-based approaches of structural reconstruction from GIXRR data lack flexibility when dealing with very thin structures (down to the nanometre scale), because a priori assumptions have to be made about the interface composition and structure. This makes it very difficult to extract reliable information about such structures. In this work, a custom free-form approach is presented, which solves this task without the need for a priori assumptions on layer or interface parameters. As a proof of principle, an optical constant profile reconstruction and GIXRR curve matching for simulated data are demonstrated. The developed approach is used to analyse the structures of multilayer LaN/B Bragg reflectors designed for the extreme UV range. The performed analysis allowed the difference in optical constant profiles of these structures produced with different processes to be revealed. The uncertainties of structural reconstruction are also discussed

GISAXS analysis of “delayed nitridation” 6.x nm multilayers

Object: La/B-based multilayersApplications: EUV lithography, X-ray fluorescenceanalysis, space research, high-intensity freeelectronlasers.Our reflectance world record [1]: 64.1% at 1.5 offnormalAOI, λ=6.65 nmApplication-desired reflectance: ~70.0%Purpose: Investigation of roughness influence on

Infrared suppression by hybrid EUV multilayer - IR lossy etalon structures

Many optical applications demand high reflectivity in a particular wavelength range and, simultaneously, suppression of radiation outside this prime range. Such parasitic radiation can lead to image distortions in imaging applications, or poor signal-noise ratios in spectroscopy. When working with sources of short-wavelength radiation based on laser-produced plasma, suppression of the scattered laser radiation is required. For these purposes we investigated a possibility to integrate an EUV reflecting multilayer coating with a resonant infrared anti-reflecting coating. Pilot samples manufactured with magnetron sputtering demonstrated 3 orders of magnitude suppression of infrared light while still reflecting 45% of the EUV radiation

EUV multilayer mirror with suppressed reflectivity for CO2 laser radiation

We have developed a multilayer mirror for extreme ultraviolet (EUV) radiation (13.5 nm) which has near-zero reflectance for IR line radiation (10.6 mm). The EUV reflecting part is based on alternating B4C and Si layers. Substantial transparency of these materials with respect to the infrared radiation allowed integrating the multilayer coating in a Fabry-Perot etalon structure with a high loss factor for 10.6 mm. Samples were manufactured using magnetron sputtering deposition technique and demonstrated suppression of the CO2 laser radiation by up to 3 orders of magnitude. The EUV peak reflectance amounts 45% at 13.5 nm, with a bandwidth at FWHM being 0.284 nm. Therefore such a mirror could replace conventional multilayer mirrors to suppress undesired spectral components in monochromatic imaging applications, including EUV photolithography

B4C/Si based EUV multilayer mirror with suppressed reflectivity for CO2 laser radiation

We have developed a multilayer mirror for extreme ultraviolet (EUV) radiation which has near-zero reflectance for CO2 laser radiation (10.6 mm). The EUV reflecting multilayer coating is based on alternating B4C and Si layers. Substantial transparency of these materials with respect to the infrared radiation allows utilizing the multilayer coating in a resonant absorbing structure for 10.6 mm. We have integrated the multilayer structure with a well known quarter-wavelength thin film absorber. Experimental samples were manufactured using magnetron sputtering deposition technique. The samples demonstrate suppression of the infrared radiation by more than two orders of magnitude. At the same time EUV peak reflectance amounts 45% at 13.5 nm, with FWHM being about 0.284 nm that matches the 2% bandwidth of a typical EUV litho tool optical system. Therefore such a mirror can replace a standard Mo/Si mirror in an EUV lithography tool to form an efficient solution for the suppression of unwanted CO2 laser radiation