Yu. Yazvitsky

On the scheme of the Eu149 → Sm149 decay

Abstract The Eu 149 → Sm 149 decay was investigated using a triple focussing β-spectrometer and γ-γ-coincidence electronic circuit for the selection of cascades. The Eu preparation was isolated from a tantalum target which had been irradiated by 660 MeV protons in the Dubna synchrocyclotron for several months. Apart from the γ-transitions with energies 256 keV, 279 keV, and 330 keV known earlier, five new transitions were found: 530 keV, 508 keV, 352 keV, 178 keV and 22 keV. The Eu 149 decay scheme is given.

Determination of boron range distribution in ion-implanted silicon by the10B(n, α)7 Li reaction

A measuring technique based on the alpha particles being released from the10B(n, α) nuclear reaction and using the time-of-flight technique at a periodically pulsing reactor was developed. Non-destructive determination for the range distribution of boron impurities in ion-implanted silicon have been performed. Projected ranges obtained in the energy region 20–80 keV are compared to calculated results and to other experiments. Examples are shown for some typical boron distributions before and after annealing the sample.

Analysis of Fluctuations of Low-Lying State Populations in Radiation Neutron Capture

An analysis is carried out of the results obtained in other papers on the intensities of secondary γ-ray transitions in neutron resonance capture for nuclei with 94 \ ≤ A ≤ 190. It is found that fluctuations of ratios of γ-ray transition intensities in the vicinity of the 4S maximum of the neutron strength function are systematically higher than those predicted by the statistical theory.

On the Eu147 decay scheme

Abstract The hard part of the Eu147 conversion electron spectrum and γ-γ coincidences in the Eu147 decay were investigated using a triple focussing β-spectrometer and γ-γ coincidence electronic circuit. The Eu preparation was isolated from a tantalum target irradiated by 660 MeV protons in the Dubna synchrocyclotron. A direct transition with v =900 keV was established and three new γ-transitions were found with energies 880 keV, 780 keV and 700 keV. The results obtained confirm the existence of 121 keV, 198 keV, 800 keV and 1080 keV levels and make it possible to introduce a new level: 900 keV into the Sm147 level scheme.

Cascadeγ-decay of compound-state of the nuclei163Dy,167Er and179Hf

An attempt has been made to reveal the general characteristics of two-quanta cascades, populating the low-lying states of an excitation energyE<1 MeV. The difference observed between the experimental cascade intensities and statistical model calculations has been analysed. Qualitative explanation of the measured two-quanta cascade intensities was achieved in the framework of a quasi-particle phonon model description of highly excited states. A considerable enhancement was revealed of the radiative strength function of theE2 transitions in the studied nuclei.

Average intensities of two‐quanta cascades in 144Nd, 165Dy and 175Yb after the capture of thermal neutrons

Two‐quanta cascades in three nuclei are investigated. The sum of their intensities makes 0,5–0,7 Γγ.

144Nd, 165Dy and 175Yb level schemes from the (n, 2γ) reaction

The (n, 2γ) reaction on thermal neutrons has been studied by the method of summation of amplitudes of coinciding pulses from two Ge(Li)‐detectors on 143Nd, 164Dy and 175Yb nuclei. Intensities of two‐quanta cascades, populating low‐lying levels of 144Nd, 165Dy, 175Yb and γ‐transition energies in these cascades have been determined.