The angular distributions for the 11.28, 11.82, and 13.79 MeV states were obtained and analyzed from the scattering of light particles by the
Be nucleus. The MDM method was used to estimate the ...radii. The radius of the 11.82 MeV state turned out to be equal to the radius of the ground state. For the 11.28 MeV the radius turned out to be increased. As for the 13.79 MeV state, the obtained value of the diffraction radius was ambiguous. The spin–parity values were estimated using the semiempirical Bohr–Mottelson formula. A conclusion was made on assignment of these states to the corresponding bands in the
Be nucleus.
A theoretical analysis of available experimental data on elastic and inelastic
C scattering in the energy region extending up to 90 MeV is performed. The parameters of a semimicroscopic potential are ...found on the basis of the dispersive optical model. The potentials found in this way are used in analyzing, by the distorted-wave Born approximation, data that the authors recently measured for inelastic scattering at energies of 65 and 90 MeV. Experimental data for the states at 3.68 and 7.55 MeV are presented for the first time. These states are considered under the assumption that, within the standard rotational model, they are members of the ground-state rotational band. A satisfactory description of angular distributions is obtained, and deformation lengths are determined. A model phenomenological form factor is used for the remaining excitations in the energy range extending up to 11 MeV. The present analysis confirms the presence of a neutron halo in the 3.09-MeV state. A similarity of form of the inelastic form factors obtained for the 8.86-, 10.996-, and 11.08 MeV states and the proximity of their radii gives grounds to assume that the
C nucleus in these three states has an enhanced size and similar structures. A comparison of the radial dependences of the form factors for the 9.90- and 8.86-MeV states shows that the wave function for the 9.90-MeV state has a substantially smaller spatial extension. These results agree with the values obtained for the radii of the states under discussion on the basis of the modified diffraction model.
The famous 7.65-MeV 0
Hoyle state of
C is always attracting plenty attention. This state has dilute 3
configuration and plays important role in nucleosynthesis. Question is if there are states analog ...to the Hoyle state in other 4
nuclei. It is possible that
-cluster 0
state in
Ne can be considered as an analog of the 7.65-MeV 0
Hoyle state of
C.
Size Isomers at Threshold States Demyanova, A. S.; Danilov, A. N.; Starastsin, V. I. ...
Physics of atomic nuclei,
08/2023, Letnik:
86, Številka:
4
Journal Article
Recenzirano
Odprti dostop
An overview is provided for a new class of states, which we have named as the size isomers. Such states are weakly bound and have an exotic structure (cluster states, halo/‘‘skin’’). The development ...of methods for measuring the radii of nuclei in their short-lived excited states led to the discovery of new classes of states. The size of a nucleus defined by the radius of its nucleon (proton and neutron) density distribution and the proton charge distribution is one of the most fundamental and important nuclear characteristics. Nuclear radius determines the basic properties of nuclei and is a consequence of the fundamental features of the strong interaction. Up to now two groups of the size isomers were identified: the excited states with halos (
Be,
Be,
C,
N) and some specific alpha-cluster states (
B,
C,
C). All the observed states are dilute, however, some indication to possible existence of more compact than the ground states was obtained as well (in
C). The phenomenon of size isomerism occurred to be not a rare one especially if we take into account rotational bands based on some of such states. The structure of size isomers is related with some new features, e.g., rotating halos, halos in continuum, different types of quasimolecular configurations. Some rudimentary signs of alpha-particle condensation (a ‘‘ghost’’ of condensate) were observed in the Hoyle state of
C, however, we cannot speak about confirmation of this ambitious theory. Analogs to the Hoyle state, expected in
B,
C,
O,
Ne near the
-emission thresholds, are considered.
Informational support is an integral part of effective land management. At the present stage, the Unified State Register of Real Estate (hereinafter - EGRN) is an informational database, which ...management decisions are based on. However, the quantity and quality of the information contained in the EGRN is not enough to pursue an effective management policy related to the country's land resources. This work presents a model of interaction between various informational systems, which allow adjusting and supplementing the EGRN database, thereby ensuring an increase in the quality of management related to the country's land resources.
A method for determining the radii of excited states of nuclei by means of (
3
He,
t
) charge-exchange reactions was proposed. Two versions of a comparison of differential cross sections for (
3
He,
...t
) reactions were considered. The first relies on a comparison with cross sections for inelastic-scattering processes leading to the formation of isobaric analog states, while the second involves (
3
He,
t
) reactions leading to the production of the ground state. The two versions in question yield similar results and make it possible to determine the radius of the first excited state of the
13
N nucleus. This state has the excitation energy of
E
* = 2.37 MeV, lying above the proton-emission threshold. The resulting radius proved to be enhanced in relation to the ground state and is close to the radius of the 3.09-MeV isobaric analog state of the
13
С nucleus, which has a neutron halo. This permitted drawing the conclusion that the
13
N nucleus in the 2.37-MeV state has a proton halo. The possibility of revealing a proton halo in other states of light nuclei is considered.
Search for Exotic States in 13C Demyanova, A. S.; Danilov, A. N.; Dmitriev, S. V. ...
JETP letters,
2021/9, Letnik:
114, Številka:
6
Journal Article
Recenzirano
New experimental data on the inelastic scattering of α-particles on
13
C at
and 90 MeV with the excitation of the
state are reported. Data are analyzed using the modified diffraction model. The ...determined rms radius of this state coincides within errors with the radius of the
8.86 MeV state in
13
C and the Hoyle state in
12
C. This result is an argument for a similar structure of these states. The unusual result for the compact 3/2
–
9.90 MeV state in
13
C has been tested by considering its isobar-analog 3/2
–
9.48 MeV state in
13
N. It has been found that these states have a normal non-increased radius.
The cluster states in light nuclei Burtebayev, N.; Janseitov, D.M.; Kerimkulov, Zh ...
EPJ Web of Conferences,
01/2018, Letnik:
194
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The differential cross-sections of the elastic and inelastic α +
11
B scattering was measured at E(α) = 29 MeV. The analysis of the data by Modified Diffraction Model (MDM) showed that the root-mean- ...square (RMS) radius of the
11
B state 3/2
-
, E* = 8.56 MeV is ~ 0.5 fm larger than that of the ground state. It is found that the radius of 3/2
-
(8.56 MeV) state in the
11
B nucleus is close to the radii of the Hoyle state in
12
C.
An experimental setup for nuclear reaction studies induced by light and heavy ions is described. It consists of a versatile Large Scattering Chamber equipped with two rotating tables for mounting ...detectors. A dedicated beam diagnostic system is used to monitor the energy spectrum of the beam on target. The system provides the necessary feedback for tuning of the K-130 cyclotron to reduce the energy spread of the accelerated beam by at least a factor of 3 down to about 0.3% of the nominal energy while maintaining beam currents around 20 pnA. At lower beam currents a 0.1% energy spread can be achieved. This improvement makes a significant impact on the scope of reaction studies possible to investigate at the Accelerator Laboratory of the University of Jyväskylä. Similar solutions could be adapted by other cyclotron facilities.
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