V. G. Kalinnikov

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.

Electromagnetic transitions in some doubly odd deformed nuclei

Abstract Nanosecond lifetimes of excited states in doubly odd deformed nuclei have been determined by in-beam measurements applying the method of delayed γ-γ coincidences as well as by experiments in the radioactive decay with the method of delayed γ-ce coincidences, respectively. Analysing the time distributions and delayed γ-ray spectra, the following half-lives of isomeric states could be obtained for the first time: T 1 2 (63.7 keV in 160 Tb ) = 60 ± 5 ns , T 1 2 (138.7 keV in 160 Tb ) = 5.7 ± 0.5 ns , T 1 2 (82.0 keV in 156 Ho ) = 1.25 ± 0.20 ns , T 1 2 (87.2 keV in 156 Ho ) = 58.5 ± 3.5 ns , T 1 2 (139.2 keV in 158 Ho ) = 1.85 ± 0.10 ns , T 1 2 (38.3 keV in 162 Ho ) = 1.2 ± 0.2 ns , T 1 2 (179.9 keV in 162 Ho ) = 8.7 ± 0.2 ns , T 1 2 (342.8 keV in 164 Ho ) = 2.6 ± 0.2 ns , T 1 2 (295.1 keV in 166 Ho ) = 1.10±0.15 ns , T 1 2 (44.6 keV in 162 Tm ) = 1.40±0.15 ns , T 1 2 ,(163.4 keV in 162 Tm ) = 1.1 ± 0.1 ns , T 1 2 (220.1 keV in 178 Ta ) = 8.5 ± 1.0 ns , T 1 2 (289.5 keV in 178 Ta ) = 2.0 ± 0.5 ns , T 1 2 (392.8 keV in 178 Ta) ≈ 1 ns, T 1 2 (316.5 keV in 186 Re ) = 0.20 ± 0.10 ns , T 1 2 (300.2 keV in 188 Re ) = 1.5 ± 0.2 ns and T 1 2 (482.2 keV in 188 Re ) = 0.26 ± 0.10 ns . Furthermore, upper limits for the half-lives of fifteen excited states in 160Tb, 164, 166Ho and 186, 188Re have been estimated. For eight isomeric levels in 186, 188Re, the lifetimes earlier determined have been remeasured. Unlike previous studies, the existence of isomeric states at 87.2 keV in 156Ho and at 179.9 keV in 162Ho is suggested. Absolute γ-ray transition probabilities are deduced and compared with single-particle estimates according to Weisskopf and Nilsson, the latter also including pairing correlations. The K-, Ω- and f-forbidden transitions can qualitatively be explained in terms of configuration mixings. Experimental El, ΔK= 1 transition matrix elements in odd-odd deformed nuclei are supposed to be appreciably influenced by higher-order vibrational admixtures coupled via RPC and p-n interaction mixings.

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.

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).

Experimental complex to study nuclei far from the beta-stability line — ISOL-facility YASNAPP-2

Abstract A complex of physics installations (YASNAPP-2 complex) developed for spectroscopic investigations of short-lived isotopes in the proton beam of the JINR phasotron is briefly described. The complex consists of a proton line, a target unit, an electromagnetic mass separator, an ion beam transport system and different spectrometric installations. Some physics results of investigations of short-lived nuclides in the rare earth region are presented.

Formation of residual nuclei with medium mass number in the reaction of protons with separated tin isotopes

Abstract The mechanism of formation of residual nuclei in the mass region 42≤A≤81 in the reactions of protons with separated tin isotopes at three protons energies 0.66, 1.0 and 8.1 GeV was investigated. The absolute cross-sections of the residual nuclei were compared with the theoretical ones calculated by the standard cascade-evaporation and the intranuclear cascad plus statistical multifragmentation models (INC + SMM). It was shown that at E p =8.1 GeV these nuclei may arise both from disintegration of the nucleus and as partners of several fragments.

Investigation of the spectra of conversion electrons and positons of the Nd fraction new isotope Nd137

Abstract Targets of Ta and Er were irradiated with a proton beam from the Dubna synchrocyclotron. The conversion electrons and the positons of the Nd spallation fraction were studied by a beta-spectrometer. A new activity with a half-life of 55±1.5 min was observed. It is established that this activity is due to the decay of Nd 137 to Pr 137 . A decay scheme is proposed.

New neutron deficient isotopes with mass numbersA=136 and 145

Previously unobserved nuclei of136Sm (T1/2=42+4 s) and145Dy(t1/2=18+3 s) have been identified using an on-line mass separating facility, operating on a 1 GeV proton beam /1/.

Structure of the (EC) decay strength function of Tb ( h)

The strength function for the (EC)-decay of ( h) is measured by the method of total -rays absorption. The same strength function is deduced from the analysis of the decay scheme and level scheme. The thus derived strength functions are in quite good agreement with each other. Also, theoretical calculation of by the microscopic quasiparticle-phonon model is carried out. The most characteristic properties of both the experimental and theoretical strength functions are pronounced resonances in .

New isotope159Lu and decay of158Lu,159,158Yb isotopes

Lutetium and ytterbium isotopes with masses A=159,158 have been produced by proton induced spallation reaction, and investigated by on-line mass separation and subsequent decay spectroscopy. A new isotope159Lu (T1/2=12.3±1 s) has been identified, and newγ-ray data have been obtained for the decay of158Lu and159, 158Yb.