Study of the neutron deficient 182–190Pb isotopes by simultaneous atomic- and nuclear-spectroscopy

Mean-square charge radii and magnetic moments have been measured for the neutron deficient lead isotopes, ^182–190Pb. The measurement was performed at the ISOLDE online mass separator, using the in-source resonance ionization spectroscopy technique. The wavelength of the first excitation step for the resonance ionization laser ion source (RILIS) was scanned over the resonance(s) whilst the α- and γ-ray spectra from the decay of the Pb isotopes were recorded as a function of the wavelength. The isotope shift and, in the case of odd-A isotopes, the hyperfine splitting were deduced. The rms-charge radii of the very neutron deficient Pb isotopes follow the smooth trend of the heavier isotopes. This finding indicates a spherical shape for the lead ground states at the neutron mid-shell (N = 104), where the excitation energy of the oblate 0⁺ state in the even isotopes reaches its minimum.     

Adaptive stabilized interferometer with laser diode

We describe a diode laser interferometer with an electronic adaptive system of fringe pattern stabilization and vibrations suppression. The interferometer allows to obtain up to four high-quality images with relative phase shifts. Also an algorithm for fringe pattern processing has been proposed.     

Spectrophotometric and luminescent analysis of polytetrafluoroethylene treated by γ-irradiation near the melting point

Radiation-modified polytetrafluoroethylene (PTFE) that exhibited intense fluorescence in the visible spectral region was prepared. Radiation modification was performed with ⁶⁰Co γ rays at 330°C, a dose of 0.2 MGy, and an atmospheric air pressure ranging from 10⁻³ to 100 mmHg. The fluorescence and electronic absorption spectra of film (95 μm) specimens irradiated under the given conditions were studied. An important role of molecular oxygen in radiation-chemical processes responsible for the generation and buildup of fluorescing entities was revealed. The spectral characteristics of the four most intense fluorescent centers were determined. It was concluded that polyene systems of π bonds-CF₂-(CF=CF)_n-CF₂-(n=4−11) in the product are responsible for fluorescence. A scheme of radiation-chemical transformation resulting in π-conjugated structures was proposed. Original Russian Text ? S.A. Khatipov, R.N. Nurmukhametov, D.I. Seliverstov, A.M. Sergeev, 2006, published in Vysokomolekulyarnye Soedineniya, Ser. A, 2006, Vol. 48, No. 2, pp. 263–270.     

Local transverse diffusion of light due to laguerre laser beam diffraction

When shading half of a Laguerre laser light beam with a semi-infinite metal screen with an imperfect edge the effect of fine structure formation in a transverse diffusion of “half-beam” light and its further evolution in the process of half-beam space propagation were experimentally revealed.     

Photooxidative decomposition of sodium dodecyl sulfate in aqueous solutions

Kinetic features and the mechanism of photooxidative decomposition of sodium dodecyl sulfate in an aqueous solution under the action of pulsed short-wavelength UV light with a continuous spectrum upon introduction of hydrogen peroxide was studied.     

Symmetric Matrices Whose Entries Are Linear Functions

Computational Mathematics and Mathematical Physics - There exists a large set of real symmetric matrices whose entries are linear functions in several variables such that each matrix in this set is...     

Resonance ionization spectroscopy of radioisotopes at the IGISOL facility, JYFL

The method of resonance ionization spectroscopy for measurements of hyperfine structures and isotope shifts of heavy elements, at the IGISOL facility, Jyväskylä, is discussed. Two laser geometries are considered, with reference to the effect they have on resolution and efficiency of measurements. Results of off line resonance ionization tests on natural sodium are reported.     

The ISOLDE RILIS pump laser upgrade and the LARIS Laboratory

On account of its high efficiency, speed and unmatched selectivity, the Resonance Ionization Laser Ion Source (RILIS) is the preferred method for ionizing the nuclear reaction products at the ISOLDE on-line isotope separator facility. By exploiting the unique electronic energy level ‘fingerprint’ of a chosen element, the RILIS process of laser step-wise resonance ionization enables an ion beam of high chemical purity to be sent through the mass selective separator magnet. The isobaric purity of a beam of a chosen isotope is therefore greatly increased. The RILIS, comprising of up to three frequency tunable pulsed dye lasers has been upgraded with the installation of a Nd:YAG pump laser as a replacement for the old Copper Vapor Laser (CVL) system. A summary of the current Nd:YAG pumped RILIS performance is given. To accompany the RILIS pump laser upgrade, a new ionization scheme for manganese has been developed at the newly constructed LAser Resonance Ionization Spectroscopy (LARIS) laboratory and successfully applied for on-line RILIS operation. An overview of the LARIS facility is given along with details of the ionization scheme development work for manganese.