Study of the anode self-trigger ability of the ME1/1 CMS Endcap Cathode Strip Chamber

The influence of the high background rates on the Cathode Strip Chamber (CSC) anode trigger ability has been studied. The investigation has been made with a P3 prototype of the CSC of ME1/1 Endcap muon station of the CMS experiment (CERN). The work has been done at the Gamma Irradiation Facility (GIF, CERN). P3 has been installed at the SPS X5c muon beam line in a background field of ¹³⁷Cs source. The CSC timing resolution and the track registration efficiency as a function of gamma rate are presented. The text was submitted by the authors in English.     

Experimental results on neutrino-electron scattering

A determination of sin² θ _w based on measurements of elastic scattering of muon-neutrinos and muon-anti-neutrinos on atomic electrons is described. These purely leptonic processes were studied using the CHARM calorimeter exposed to neutrino and antineutrino wide-band beams at the CERN super proton synchrotron. A total of 83±16 neutrino-electron and 112±21 antineutrino-electron events have been detected. From the measurement of the ratio of muon-neutrino and muon-antineutrino cross-sections a value of sin² θ _w =0.211±0.037 was obtained.     

Problems of homogeneous irradiation of Si ingots more than 200 mm in diameter under neutron doping

The problem of homogeneous irradiation of Si ingots of large diameter (i.e., comparable with the thermal neutron diffusion length in silicon—20 cm) by thermal neutrons is considered. The effect of neutron absorption on the irradiation homogeneity is discussed. It is established for some usual cases of neutron doping that the neutron distribution in the irradiation zone affects the irradiation homogeneity. The results obtained can be useful for choosing and designing the irradiation zone for neutron doping of silicon.     

Measurement of thicknesses of thin films by the Fourier spectrometry method

A Fourier spectrometry method for measuring the thickness of thin and ultrathin films with the help of an additional peak that depends on the optical thickness of the deposited film and is situated outside the region of the central peak of the interferogram is proposed. The experiment demonstrates the necessity of considering the change in optical path in the substrate that is induced by the deposited film.     

Optimization of the signal-to-background ratio in energy-dispersive X-ray fluorescence analysis using a Si(Li) detector

A mathematical model of an energy dispersive X-ray fluorescence spectrometer is discussed based on the analysis of the processes of radiation transport in the sample and in the detector and electron transport in the detector. The results of calculations performed according to the proposed model were compared with the available experimental data. The effect of the parameters of primary X-radiation and the detector’s thickness on the signal-to-background ratio was calculated. It was shown that with a change of the primary radiation source and the detector’s thickness, the signal-to-background ratio of the analytical signal varied by several orders of magnitude.     

Modern Russian mass spectrometers for the atomic industry

Product quality control within the nuclear fuel cycle is a subject of special concern in Russia nowadays. Earlier, mass spectrometers of foreign production were commonly used for elemental and isotope analysis of samples. Currently, a series of domestic mass spectrometers MTI-350 has been developed and their production has been organized in Russia. The series comprises an automated MTI-350G mass spectrometer for the isotope analysis of uranium hexafluoride; thermal ionization MTI-350T mass spectrometer for the isotope analysis of uranium, plutonium, and mixed oxide (MOX) fuels; an MTI-350GS mass spectrometer for controlling the production of uranium hexafluoride; and an MTI-350GP mass spectrometer for the determination of the impurity concentration in uranium hexafluoride. The article considers operation principles, analytical characteristics, and the advantages of the above mass spectrometers.     

Deep oxidation of chlorobenzene on complex catalysts

Deep oxidation of chlorobenzene on γ-alumina catalysts whose active components are V₂O₅, CuCl, or their mixture was studied in relation to the temperature, contact time, and load on the catalyst. The activation energy of the chlorobenzene oxidation on the CuCl-V₂O₅/γ-Al₂O₃ catalyst was determined.     

Extreme value statistics in Raman fiber lasers

We present the numerical study of the statistical properties of the partially coherent quasi-CW high-Q cavity Raman fiber laser. The statistical properties are different for the radiation generated at one or many cavity passes. It is found that rare extreme events are generated at the far spectral wings of the spectrum. The mechanism of the extreme events generation is a turbulent-like four-wave mixing of numerous longitudinal generation modes.