Acceleration mass spectrometer of the Budker Institute of Nuclear Physics for biomedical applications

An accelerator mass spectrometer (AMS) made at the Budker Institute of Nuclear Physics (BINP), Siberian Branch, Russian Academy of Sciences, is installed in the Geochronology of the Cenozoic Era Center for Collective Use for the carbon 14 dating of samples. Distinctive features of the BINP AMS include the use of a middle energy separator of ion beams, magnesium vapor target as a stripping target, and a time-of-flight telescope with thin films for accurate ion selection. Results of experiments measuring the radiocarbon concentration in test samples with radiocarbon labels for biomedical applications are presented.     

Manifestation of optical activity in different materials

Various manifestations of optical activity (OA) in crystals and organic materials are considered. Examples of optically active enantiomorphic and nonenantiomorphic crystals of 18 symmetry classes are presented. The OA of enantiomorphic organic materials as components of living nature (amino acids, sugars, and proteins) is analyzed. Questions related to the origin of life on earth are considered. Examples of differences in the enantiomers of drugs are shown. The consequences of replacing conventional left-handed amino acids with additionally right-handed amino acids for living organisms are indicated.     

Study of primary cosmic rays on the Moon’s surface and in orbit around the Moon

A mathematical model for experiments aimed at studying the primary cosmic rays on the Moon’s surface and in orbit around the Moon is considered. The feasibility of simultaneously registering in three components (secondary neutrons, gamma rays, and radio emission) particles of primary cosmic rays via reverse current in showers developing in the lunar regolith is demonstrated.     

A laser diode with feedback using a fibre delay line as a stable-frequency signal generator and potential fibre sensor

An optical fibre communication line (OFCL) closed-circuited into a ring network is considered as a controlled automodulated oscillation source. Theoretical and experimental investigations of the amplitude and frequency of automodulation for stationary self-consistent automodulation and external synchronization regimes in such a system are given on the basis of a balance equations analysis. It is shown that this OFCL ring can be used as an optical fibre tester and sensor.     

Numerical investigation of multidimensional cosmological models based on the Weyl integrable geometry

The dynamics of multidimensional cosmological models based on the Weyl integrable geometry are investigated by means of numerical methods. Models are considered in space and in the presence of matter, the latter modeled by an ideal liquid and a nonminimal scalar field. Sufficient conditions are obtained under which cosmological singularity is absent and the scenario of dynamic dimensional reduction is realized.Scientific Research Center of PV. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 107–113, May, 1995.     

Application of light-scattering spectroscopy to the investigation of inorganic glasses (Review)

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 51, No. 6, pp. 887–903, December, 1989.     

Film growth and mechanism of LICVD of chromium films from Cr(CO)6 at 248 nm

The probe-beam transmission method was used to study the chemical vapor deposition of chromium films due to photodecomposition of Cr(CO)₆ by pulsed excimer laser radiation at 248 nm in a reversed-substrate configuration, where the film forms on the quartz entrance window of the deposition cell. The dependence of the deposition rate and the film formation time on the laser pulse intensity and repetition rate as well as on the Ar buffer gas pressure was determined for different stages of the deposition process. The experiments were performed at room temperature, on a deposition area of about 0.15 cm², with laser fluences up to 100mJ cm^–2, pulse repetition rates between 5 and 80 pps and buffer gas pressures between 10 and 700 mbar. The results are discussed within the framework of a simple model for LICVD. They reveal the dominant role of gas-phase photodissociation and diffusion in chromium film deposition under the conditions employed. Some results concerning the morphology and the depth distribution of Cr, O, and C in films deposited in the reversed-substrate configuration are also presented.     

Spectral characteristics of non-collinear acousto-optic tunable filters

The bandpass width and the diffraction efficiency of a non-collinear acousto-optic tunable filter are considered as functions of the optical wavelength for fixed values of the direction of propagation of the optic wave, the length of the acousto-optic interaction and the power density of the controlling RF-signal. A comparison between the calculated and the experimentally measured spectral dependencies is discussed and illustrated from the viewpoint of practical application for a TeO₂ filter. It is shown that in the approximation used, satisfactory agreement can be achieved between the experimental and calculated dependencies.