Search for states with enlarged radii in excited states of 12B

An experiment was done to search for states with a neutron halo in 12B. The measurements were carried out at the cyclotron of the University of Jyvaskyla (Finland) using Large Scattering Chamber (LSC). The idea of the work was to search for two states with the expected neutron halo, 1 ̄ and 2 ̄. Differential cross sections with excitation of 12B states, including abovementioned states, were observed. The preliminary calculations on halo radii by the method of asymptotic normalization coefficients for the 2 ̄ and 1 ̄ states which are in a discrete spectrum gave following values: 5.6 fm and 7.4 fm, which is much larger than the radius of the valence neutron in the ground state. But strictly the presence of a neutron halo can be confirmed only for 1 ̄ state. The 2 ̄ state can be considered only as candidate for halo. An unexpected result was obtained for the 3 ̄, 3.39 MeV state, which is in continuum 19 keV above the decay threshold 12B → 11B + n, preliminary estimation for its halo radius is ∼ 6.5 fm. This indicates that the halo can be present in this state as well. But strict conditions for neutron halo are not fulfilled in the same way as for 2 ̄ state. Until now, the neutron halo in unbound states has been observed only for the members of the rotational bands

Fission of 180,182,183Hg and 178Pt nuclei at intermediate excitation energies

Purpose: The study of asymmetric and symmetric fission of 180,182,183Hg and 178Pt nuclei as a function of their excitation energy and isospin. Methods: Mass-energy distributions of fission fragments of 180Hg, 178Pt (two protons less than 180Hg), and 182Hg (two neutrons more than 180Hg) formed in the 36Ar+144Sm,142Nd, and 40Ca+142Nd reactions were measured at energies near and above the Coulomb barrier. Fission of 183Hg obtained in the reaction of 40Ca with 143Nd was also investigated to see if one extra neutron could lead to dramatic changes in the fission process due to the shape-staggering effect in radii, known in 183Hg. The measurements were performed with the double-arm time-of-flight spectrometer CORSET. Results: The observed peculiarities in the fission fragment mass-energy distributions for all studied nuclei may be explained by the presence of a symmetric fission mode and three asymmetric fission modes, manifested by the different total kinetic energies and fragment mass splits. The yield of symmetric mode grows with increasing excitation energy of compound nucleus. Conclusions: The investigated properties of asymmetric fission of 180,182,183Hg and 178Pt nuclei point out the existence of well-deformed proton shell at Z≈36 and a less deformed proton shell at Z ≈ 46.peerReviewe

Asymmetric and symmetric fission of excited nuclei of 180,190Hg and 184,192,202Pb formed in the reactions with 36Ar and 40,48Ca ions

Background: Observation of asymmetric fission of 180Hg has led to intensive theoretical and experimental studies of fission of neutron-deficient nuclei in the lead region. Purpose: The study of asymmetric and symmetric fission modes of 180,190Hg and 184,192,202Pb nuclei. Methods: Mass-energy distributions of fission fragments of 180,190Hg and 184Pb formed in the 36Ar+144,154Sm and 40Ca+144Sm reactions, respectively, at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET and compared with previously measured 192,202Pb isotopes produced in the 48Ca+144,154Sm reactions. The mass distributions for 180,190Hg and 184,192,202Pb together with old data for 187Ir, 195Au, 198Hg, 201Tl, 205,207Bi, 210Po, and 213At [J. Nucl. Phys. 53, 1225 (1991)] have been decomposed into symmetric and asymmetric fission modes. The total kinetic-energy distributions for different fission fragment mass regions have been analyzed for 180,190Hg and 184Pb. Results: The stabilization role of proton numbers at Z≈36, 38, Z≈45, 46, and Z=28/50 in asymmetric fission of excited preactinide nuclei has been observed. The high (≈145−MeV) and the low (≈128−MeV) energy components have been found in the total kinetic-energy distributions of 180,190Hg fission fragments corresponding to the fragments with proton numbers near Z≈46 and Z≈36, respectively. In the case of fission of 184Pb only the low-energy component (≈135MeV) for the fragments with masses corresponding to the proton numbers Z≈36 and 46 has been found. Conclusions: The studied properties of asymmetric fission of 180,190Hg and 184,192,202Pb nuclei point out the existence of well deformed proton shell at Z≈36 and less deformed proton shell at Z≈46.peerReviewe

INVESTIGATION OF (P, XP) AND (P, XΑ) REACTIONS OF 30-MEV PROTONS WITH THE 103RH NUCLEUS

Double-differential and integral cross sections of the (p, xp) and (p, xα) reactions on the 103Rh nucleus were measured at Ep = 30 MeV using a proton beam delivered by the U-150M cyclotron of the Institute of Nuclear Physics (Almaty, Kazakhstan). A self-sustaining 103Rh foil of 3 µm thickness was used as a target. The obtained experimental results were compared with the TENDL-2019 nuclear data library, which provides the output of the TALYS nuclear model code. We assert that the TENDL-2019 evaluations provide a valid description of the obtained experimental data

The cluster states in light nuclei

The differential cross-sections of the elastic and inelastic α +11B 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 11B 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 11B nucleus is close to the radii of the Hoyle state in 12C

The cluster states in light nuclei

The differential cross-sections of the elastic and inelastic α +11B 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 11B 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 11B nucleus is close to the radii of the Hoyle state in 12C

Investigation of the elastic and inelastic scattering of 4He from 11B in the energy range 29-50.5 MeV

We have measured the angular distributions for the elastic and inelastic scattering of 4He from 11B in the isochronous cyclotron U-150 M INP RK. The extracted α-particles beam has been accelerated to energy 29 MeV and then directed to 11B target. The experimental results were analyzed within the framework of both the optical model using different complex potential and the double folding potential obtained with different density-dependent NN interactions which give the corresponding values of the nuclear incompressibility K in the Hartree-Fock calculation of nuclear matter.peerReviewe

Underground investigation of extensive air showers spectra at high energy range of cosmic rays and other research in the Pyhäsalmi mine

Abstract High energy particles reaching the Earth’s atmosphere are known as cosmic rays. As a result of interactions with nuclei of air molecules, cosmic rays induce showers of secondary particles, which can be divided into 3 components: electromagnetic, hadronic and muonic components. The Experiment with Multi Muon Array (EMMA), located at the depth of 75 m in the Pyhäsalmi mine in Finland, investigates the muonic component of the Extensive Air Showers (EAS) to deduce the direction, energy, and the mass of the primary cosmic ray particles. In this paper we give a concise description and methodology used by EMMA followed by a brief review of the C14 experiment. Finally, we review the feasibility to host in the Pyhäsalmi mine a future large-scale liquid-based neutrino detector and implement a novel concept of acoustic detection of neutrinos in bedrock utilizing the network of many kilometers of boreholes surrounding the now-exploited ore body.Pеферат Жер атмосферасы арқылы өтетін жоғары энергия бөлшектерінің ағыны ғарыштық сәулелер ретінде белгілі. Жоғары энергетикалық ғарыш сәулесі бөлшектерінің ядролық өзара әрекеттесуі нәтижесінде екінші реттік бөлшектер өндіреді, оларды 3 құрамдас бөлікке бөлуге болады: электромагниттік, адрондық және мюондық. Финляндиядағы Пюхясалми шахтасында 75 м тереңдікте орналасқан мульти-мюон массиві (EMMA) бар Эксперимент бастапқы ғарыш сәулесі бөлшектерінің бағытын, энергиясын және массасын шығару үшін кең әуе нөсерлерінің (EAS) мюондық құрамын зерттейді. Бұл мақалада біз Эмма қолданатын қысқаша сипаттама мен әдіснаманы, содан кейін C14 экспериментіне қысқаша шолу береміз. Ақырында, біз шахтада болашақ ірі көлемді сұйық нейтринді детекторды Пюхясалми орналастыру мүмкіндігін қарастырамыз және қазіргі қолданыстағы кең көлемі көптеген километрлік ұңғымалар желісін пайдалана отырып, жартастағы жыныстардағы нейтриноны акустикасын анықтаудың жаңа тұжырымдамасын іске асырамыз

Fission of Hg-180,Hg-182,Hg-183* and Pt-178* nuclei at intermediate excitation energies

Background: The nature of asymmetric fission of preactinides is not yet understood in detail, despite intense experimental and theoretical studies carried out at present. Purpose: The study of asymmetric and symmetric fission of Hg180,182,183 and Pt178 nuclei as a function of their excitation energy and isospin. Methods: Mass-energy distributions of fission fragments of Hg180, Pt178 (two protons less than Hg180), and Hg182 (two neutrons more than Hg180) formed in the Ar36+Sm144, Nd142, and Ca40+Nd142 reactions were measured at energies near and above the Coulomb barrier. Fission of Hg183 obtained in the reaction of Ca40 with Nd143 was also investigated to see if one extra neutron could lead to dramatic changes in the fission process due to the shape-staggering effect in radii, known in Hg183. The measurements were performed with the double-arm time-of-flight spectrometer CORSET. Results: The observed peculiarities in the fission fragment mass-energy distributions for all studied nuclei may be explained by the presence of a symmetric fission mode and three asymmetric fission modes, manifested by the different total kinetic energies and fragment mass splits. The yield of symmetric mode grows with increasing excitation energy of compound nucleus. Conclusions: The investigated properties of asymmetric fission of Hg180,182,183 and Pt178 nuclei point out the existence of well-deformed proton shell at Z≈36 and a less deformed proton shell at Z ≈ 46