I.M. Kapitonov

Single-particle properties of the 1f2p shell nuclei on the basis of proton stripping and pick-up data

Abstract The experimental data on proton stripping and pick-up on even-even targets with Z from 20 to 28 are analyzed jointly using the spin and parity data obtained in different experiments. The general features in the distribution of the spectroscopic strengths among nuclear states are revealed. Spins of 10 nuclear states and parity of one state are predicted. The shell-structure parameters are calculated. It is found that the single-particle forces are essential in the above-noted experiments.

Photoproton cross section for 26Mg in the giant dipole resonance region

Abstract Using bremsstrahlung from the 35 MeV betatron the 26 Mg( γ , x p) reaction cross section has been obtained in the excitation energy region up to 29 MeV. The role of isospin splitting in the formation of a giant dipole resonance is discussed in the case of light nuclei.

Photoproton energy spectra and isospin effects in the decay of highly excited states of Ni isotopes

Abstract The technique of the difference proton spectra is used to study the decay properties of highly excited states of the 58 Ni and 60 Ni isotopes in the energy region of the giant dipole resonance. The proton transition strengths to specific final states from particular initial states have been extracted. Experimental data are interpreted in terms of isospin splitting of the giant dipole resonance.

Structure in the photoneutron cross section of 24Mg and 26Mg

Abstract With bremsstrahlung from a 35 MeV betatron, the 24,26 Mg( γ , x n) reaction cross sections are obtained. The role of various factors in the formation of the giant resonance in 24 Mg and 26 Mg is considered.

Decay channels of the giant dipole resonance in 26Mg

The energy spectra of photoprotons from 26Mg have been measured with bremsstrahlung at five values of the end-point energy Eγmax, namely, at 19.5, 20.5, 22.0, 24.5 and 27.0 MeV. Using the difference spectra technique, we have determined the main decay channels of the states of the giant dipole resonance (GDR) of 26Mg. The photoproton spectra have been used to obtain the cross sections for the formation of the final nucleus of the 26Mg(γ, p)25Na reaction in its various states. The magnitude of the configurational splitting of the GDR of 26Mg has been estimated. Relevant data from other studies have been utilized to calculate the isospin components of the GDR of 26Mg within the framework of a combined model for the decay of the giant resonance, with isospin taken into account. A new isospin interpretation of the cross sectios for the photoproton and photoneutron reactions on the 26Mg nucleus is proposed.

A combined model for decay of the giant dipole resonance

Abstract A simple model for decay of the giant dipole resonance is described that takes into account the semidirect, pre-equilibrium, and equilibrium mechanisms of the photonucleon emission. The semidirect photoeffect is treated within the framework of the R -matrix theory in the shell model. The wave function for the doorway dipole state is constructed using the generator procedure that offers the possibility to obtain simple formulas for a calculation of the semidirect component of the photonucleon spectra. The problem of the inclusion of isospin effects is treated. A reasonable agreement between theoretical and experimental photoproton spectra has been obtained.

A semimicroscopic calculation of the photodisintegration of the 32S nucleus

Abstract Using the semimicroscopic nuclear vibration model and the combined model for giant resonance decay, we have calculated the giant dipole resonance structure and the partial photo-nucleon cross sections for 32S. The theoretical parameters were estimated from the spectroscopic data. The calculation satisfactorily describes the structure and decay characteristics of the 32S giant resonance. It has been shown that the statistical mechanism plays a significant role in the photodisintegration of 32S.

Systematics of the single-particle properties of the 1d2s shell nuclei

Abstract Experimental data on pickup and stripping reactions have been used to investigate single-particle properties of the most stable nuclei of the 1d2s shell. Populations of proton subshells and single-particle energies of the nuclear hamiltonian are obtained.

Photodisintegration of Molybdenum Isotopes

The process of photodisintegration of molybdenum isotopes was studied using the induced activity method. The yields of isotopes produced as a result of photonuclear reactions on a natural mixture of molybdenum isotopes were determined at an electron accelerator energy of 67.7 MeV. A comparison of the experimental results with the theoretical calculation carried out using the combined model of photonucleon reactions shows that the model gives a fair description of the experimental yields of photonucleon reactions on all molybdenum isotopes except for 92Mo. The high yields of the proton channels of photonuclear reactions on the 92Mo isotope and low yields of the corresponding neutron channels are interpreted based on the shell structure of molybdenum isotopes.

Isotopic effect in the width of a giant dipole resonance in light nuclei

An isotopic effect in the widths of giant dipole resonances is established on the basis of an analysis of the latest systematics of photoabsorption cross sections for nuclei containing 12 to 65 nucleons. This effect arises owing to isospin splitting of a giant resonance and is enhanced by its configuration splitting.