G.D. Alkhazov

The study of short-lived nuclei in the regionZ=59–68

Abstractβ+ -ray endpoint energies for mass-separated samples of neutron deficient Rare-Earth isotopes have been measured using an intrinsic germanium detector. QEC values have been obtained and new isomeric states have been identified for the first time.

A new highly efficient selective laser ion source

Abstract A new high-temperature resonant laser ion source is described to be used at on-line mass separators.

A new highly efficient method of atomic spectroscopy for nuclides far from stability

Abstract A new high-efficient method for measuring isotope shifts and hyperfine structures in optical transitions of radioactive atoms is described. The method is based on application of laser resonance ionization in a mass separator ion source. The high sensitivity of the method results from a high efficiency of the laser ion source and a low background of the detection system, which uses counting α-particles following the decay of the isotope under investigation. The isotope shifts and hyperfine structures for 154–156Yb in the 555.6 nm transition have been measured. It is shown that in a number of cases this method allows measurements to be carried out for isotopes with a production rate in the target down to 1–10 atoms per second.

Nuclear electromagnetic moments and charge radii of deformed thulium isotopes with the mass numbers A = 157−172

Abstract Hyperfine structures and isotope shifts of thulium isotopes in the mass range 157–172 have been measured in the atomic transitions 4f 13 6s 2 −4f 12 5d6s 2 (589.565 nm) and 6s 2 −6s6p (597.13 nm), using resonance ionization Spectroscopy at the IRIS facility. Nuclear magnetic dipole and electric quadrupole moments, and the changes in mean square charge radii have been obtained. They are analysed within the framework of the microscopic-macroscopic approach and the Hartree-Fock method, revealing single-particle and collective properties. Some conclusions on effective nucleon-nucleon interactions are drawn.

Nuclear sizes of 40,48Ca and 32,34S isotopes determined from 1 GeV proton elastic scattering

Abstract Differential cross sections for 1 GeV proton elastic scattering from 40,48 Ca and 32,34 S have been measured. The parameters of the nucleon distributions were obtained from an analysis of the experimental data. The difference between the neutron distributions in 40 Ca and 48 Ca is discussed in particular.

Identification of the proton drip line

A group of proton emitters of Au, Ir, Re, Ta has been identified by means of mass values derived from the experimental data. The proton drip line has been determined. It is shown that on the boundary of the proton stability the values of proton pairing energies increase by about 50% as compared with the isotone nuclei near the betastability line.

Differential cross sections of 1 GeV proton scattering from 12C

Abstract This paper presentd differential cross sections for elastic and inelastic (with excitation of the 4.43 MeV level) scattering of 1 GeV protons from 12 C in the angle range θ cm = 10° − 10°. The measurements were carried out with the energy resolution FWHM = 3.5 MeV.

Beta-decay energy measurements using total gamma-absorption spectroscopy

An application of the totalγ-absorption (TGA) spectroscopy to measurements of theβ-decay energies (Q) for nuclei far from stability is described. This approach provides theQ-values with accuracies up to 60 keV. TheQ values determined by this method at the IRIS facility for 64 nuclides in the mass region fromA=76 toA=165 are presented.

Application of a high efficiency selective laser ion source at the IRIS facility

Abstract Results of the first experiments performed at the mass separator IRIS using a selective laser ion source are presented.

New neutron deficient lutetium isotopes

On the IRIS facility the new neutron deficient157,158,160,161,163Lu isotopes have been produced in spallation induced by 1 GeV protons on a tungsten or tantalum target, and identified by mass separation and the subsequent decay spectroscopy (X-, gamma-, and alpha ray spectroscopy).