K. Ya. Gromov

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.

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.

The decay of 152Tb

Abstract The conversion electron spectrum, electron-gamma and β + -gamma coincidence spectra are investigated, and the gamma-ray spectrum is studied in two Ge(Li) semiconductor spectrometers. A decay scheme 152 Tb → 152 Gd is suggested, including many new levels among which two 0 + states at 1484.0 and 2720.7 keV. Relative intensities at 0.2 : 0.3 : 1 are found for positon branches from 152 Tb to the 615.6 keV (0 + ), 344.4 keV (2 + ) and to the ground state of 152 Gd. Spin 1 − is ascribed to the ground state of 152 Tb. Spin assignments are being made for the following excited levels: 755.6 keV 4 + , 1109.8 keV 2 + , 1123.8 keV 3 − , 1606.1 keV 2 + , 1643.9 keV 1 − , 1862.3 keV 2 + and 1942.5 keV 2 + .

Decay of 167Yb (18min) to 167Tm

Abstract The level scheme of the deformed nucleus 167Tm has been investigated in the decay of 167Yb using germanium detectors and a magnetic β-spectrograph. The conversion electron spectrum, single γ-ray spectra and prompt and delayed γ-γ coincidences were measured. A decay scheme is proposed involving 25 excited states in 167Tm and approximately 60 of the more than 100 new transitions. In the low-energy region the first members of the rotational bands 1 2 + [411], 1 2 − [541], 7 2 + [404], 7 2 − [523] and 3 2 + [411] could be identif interpretation of the high-lying levels are discussed on the basis of microscopic theory.

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/.

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.

Decay of 161Er to 161Ho

The level scheme of the deformed odd-proton nucleus 161Ho was investigated in the electron-capture decay of 161Er using germanium detectors, a magnetic β-spectrograph and two π√2 double-focussing β-spectrometers. In addition to the measurements of singles γ-ray and conversion-electron spectra extensive γ-γ coincidence measurements were performed. A decay scheme is proposed involving 37 excited states in 161Ho. In the low-energy region the first members of the rotational bands 72-[523], 12+[411], 72+[404], 32 +[4411], 12−[541], 52+[413] and52−[532] were identified. Furthermore, the first two members of the γ-vibrational band K0-2M built on the ground state and an additional band with the probable quantum characteristic Kπ = 52+ (band head at 446.9 keV) have been found. Possible interpretations of the high-lying levels are discussed on the basis of current models.

Excited states of the doubly odd deformed nucleus 160Tm

Abstract The decay of 4.8 min 160 Yb has been investigated by means of Ge(Li) detectors, toroidal and magnetic-lens β-spectrometers and scintillation counters. The singles spectra of γ-rays and conversion electrons as well as prompt and delayed γ-γ and γ-ce coincidences have been measured. The 160 Tm level scheme is proposed including 94.5% of the total γ-ray intensity observed in the 160 Yb decay. The lifetimes of the 42.02, 174.40 and 215.78 keV states have been determined to be 1.6±0.3, 17±1 and 0.65±0.15 ns, respectively. From the analysis of the experimental data, the quantum characteristics of 160 Tm levels are proposed. Experimental γ-ray transition probabilities are compared with Weisskopf and Nilsson estimates, the latter also taking into account pairing correlations.