Photoemission of polarized electrons from InAlGaAs/GaAs superlattices with minimum conduction band offsets

Photoemission of polarized electrons from heterostructures based on InAlGaAs/GaAs superlattices with minimum conduction-band offsets is investigated. The comparison of the excitation energy dependence of the photoemission polarization degree with the calculated spectra make it possible to determine the polarization losses at different stages of the photoemission. A maximum polarization of P = 91% and a quantum yield of 0.14% are close to the best results obtained for photocathodes on the basis of strained semiconductor superlattices.     

A modified electrochemical procedure for isolating <Superscript>177</Superscript>Lu radionuclide

A cell for isolating ¹⁷⁷Lu from a neutron-irradiated ¹⁷⁶Yb target was developed. The procedure involves a combination of two processes: contact reduction of Yb from acetate–chloride solution on sodium amalgam, followed by electrolysis of the solution on a mercury cathode. The process conditions were chosen so that the adjustment of the working solution characteristics (composition, pH, etc.) in going from contact reduction to electrolysis was not required. Both processes are performed in one cell, which reduces the ¹⁷⁷Lu loss. On an installation consisting of two cells, the decontamination factor of the ¹⁷⁷Lu solution from Yb of up to 10⁶ was reached, which is necessary for obtaining a ¹⁷⁷Lu preparation of high specific activity.     

Focusing of Novosibirsk Free Electron Laser (NovoFEL) radiation into paraxial segment

Abstract

We demonstrate results of studies of a silicon binary diffractive optical element (DOE) focusing a terahertz laser Gaussian beam into a paraxial segment. The characteristics of the DOE were examined on a Novosibirsk Free Electron Laser beam of 141-μm wavelength.     

掺硫硒化镓晶体在太赫兹波段的光学特性

利用太赫兹时域光谱技术测量了掺硫硒化镓(GaSe1-xSx)晶体在太赫兹波段的光学参数,包括折射系数、吸收系数等.使用自由空间电光取样法获得了太赫兹电磁波的脉冲波形.对不同硫掺杂量的硒化镓晶体进行了研究,在硫的掺杂量为0,0.01,0.14,0.26,0.37时,在0.2-2.0THz测得了GaSe1.S.的折射系数、...     

Water velocity determination in the gaps of irt-3M, -4M fuel assemblies

Experiments on measuring the water velocity in the gaps between the fuel elements of an IRT-3M eight-tube fuel assembly with 90% fuel enrichment, used in pool and tank research reactors, are described. The experiments were performed on a hydraulic facility at the National Research Center Kurchatov Institute. The velocity was determined from the dynamic head in the gaps of a model fuel assembly. These velocities were used as a basis for determining the water flow rate in each gap and the total flow rate through a fuel assembly. Comparative hydraulic calculations of IRT-3M fuel assemblies with 90% fuel enrichment and IRT-4M fuel assemblies with 19.7% enrichment, developed as a replacement for IRT-3M, are described. It is shown that if the IRT-4M gaps decrease to 1.85 mm, then the water velocity in them will decrease by only 5% as compared with IRT-3M.     

Characteristics of position sensitive detector pixels based on promising inorganic scintillators LaBr3:Ce and CeBr3

The energy resolution of different-geometry LaBr₃:Ce and CeBr₃ scintillation crystals grown by the Institute of Solid State Physics (Russian Academy of Sciences) by the order of the Skobel’tsyn Institute of Nuclear Physics (Moscow State University) was measured. The measurements were taken at energies of detected γ rays ranging from 20 keV to ～5 MeV. The samples under investigation were shaped as cylinders with a diameter of 0.5 cm and heights of 1.5 and 3.0 cm. The positional resolution along the crystal axis was also investigated for the CeBr₃ crystals by measuring the amplitudes of the scintillation signals from the opposite crystal ends. It was shown that the ratio of these amplitudes was dependent on the distance from a crystal end surface to the interaction point of a γ quantum inside the detector according to the linear law. The positional resolution along the crystal length appeared to be comparable to the crystal diameter. The results of the study suggest that CeBr₃ crystals have a great potential as position-sensitive elements of space-sensitive detectors for high-energy charge particles and γ rays.     

Improving the annealing of cold-rolled 65Γ steel to comply with the ISO/TU 16949:2002 standard

Production processes are evaluated on the basis of statistical process control (SPC) in order to ensure that cold-rolled strip made from 65Γ steel corresponding to Technical Specifications TU 14-4-1382-86 complies with the ISO/TU 16949:2002 standard. The statistical applicability and degree of controllability of SPC are determined, and corrections are introduced in the technology.     

Choice of Agreement Criterion for Determining the Distribution Law of a Measured Quantity

The method of simulation modeling was used to perform a comparative analysis of the characteristics of a number of agreement criteria under conditions of restricted sampling. A method is proposed for modifying the ² criterion for the purpose of broadening its range of application.