24 results on '"Kheswa, B.V."'
Search Results
2. γ-ray emission in proton-induced nuclear reactions on natC and Mylar targets over the incident energy range, E = 30 – 200 MeV. Astrophysical implications
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Rahma, Y., primary, Ouichaoui, S., additional, Kiener, J., additional, Lawrie, E.A., additional, Lawrie, J.J., additional, Tatischeff, V., additional, Belhout, A., additional, Moussa, D., additional, Yahia-Cherif, W., additional, Benhabiles-Mezhoud, H., additional, Bucher, T.D., additional, Dinoko, T.R.S., additional, Chafa, A., additional, Conradie, J.L., additional, Damache, S., additional, Debabi, M., additional, Deloncle, I., additional, Easton, J.L., additional, Fouka, M., additional, Hamadache, C., additional, Hammache, F., additional, Jones, P., additional, Kheswa, B.V., additional, Khumalo, N.A., additional, Lamula, T., additional, Majola, S.N.T., additional, Ndayishimye, J., additional, Negi, D., additional, Noncolela, S.P., additional, Ouziane, S., additional, Papka, P., additional, Peterson, S., additional, Kumar Raju, M., additional, Ramanathan, V., additional, Rebeiro, B.M., additional, de Séréville, N., additional, Sharpey-Schafer, J.F., additional, Shirinda, O., additional, Wiedeking, M., additional, and Wyngaardt, S., additional
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- 2023
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3. The Rigorous Test of the Generalized Brink–Axel Hypothesis in the \(A=138\) Nuclear Mass Region
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Kheswa, B.V., primary
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- 2023
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4. Experimental observation of the M1 scissors mode in 254No
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Bello Garrote, F.L., primary, Lopez-Martens, A., additional, Larsen, A.C., additional, Deloncle, I., additional, Péru, S., additional, Zeiser, F., additional, Greenlees, P.T., additional, Kheswa, B.V., additional, Auranen, K., additional, Bleuel, D.L., additional, Cox, D.M., additional, Crespo Campo, L., additional, Giacoppo, F., additional, Görgen, A., additional, Grahn, T., additional, Guttormsen, M., additional, Hagen, T.W., additional, Harkness-Brennan, L., additional, Hauschild, K., additional, Henning, G., additional, Herzberg, R.-D., additional, Julin, R., additional, Juutinen, S., additional, Laplace, T.A., additional, Leino, M., additional, Midtbø, J.E., additional, Modamio, V., additional, Pakarinen, J., additional, Papadakis, P., additional, Partanen, J., additional, Renstrøm, T., additional, Rezynkina, K., additional, Sandzelius, M., additional, Sarén, J., additional, Scholey, C., additional, Siem, S., additional, Sorri, J., additional, Stolze, S., additional, and Uusitalo, J., additional
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- 2022
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5. Experimental observation of the 1 Scissors Mode in No
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Bello Garrote, F.L., Lopez-Martens, A., Larsen, A.C., Deloncle, I., Péru, S., Zeiser, F., Greenlees, P.T., Kheswa, B.V., Auranen, K., Bleuel, D.L., Cox, D.M., Crespo Campo, L., Giacoppo, F., Görgen, A., Grahn, T., Guttormsen, M., Hagen, T.W., Harkness-Brennan, L., Hauschild, K., Henning, G., Herzberg, R.D., Julin, R., Juutinen, S., Laplace, T.A., Leino, M., Midtbø, J.E., Modamio, V., Pakarinen, J., Papadakis, P., Partanen, J., Renstrøm, T., Rezynkina, K., Sandzelius, M., Sarén, J., Scholey, C., Siem, S., Sorri, J., Stolze, S., and Uusitalo, J.
- Abstract
We present the first experimental evidence of the scissors mode in the superheavy nucleus $^{254}$No produced in the $^{208}$Pb($^{48}$Ca, 2nγ))$^{254}$No reaction. The spectrum of γ rays emitted by the excited $^{254}$No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of $^{254}$No were performed. The observed enhancement is reproduced by including an M1 component in the γ strength function with total strength B(M1↑)=11.8(19)μN2. This is in good agreement with the integrated M1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei.
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- 2022
6. First observation of the coexistence of multiple chiral doublet bands and pseudospin doublet bands in the A ≈ 80 mass region
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Mu, L., primary, Wang, S.Y., additional, Liu, C., additional, Qi, B., additional, Bark, R.A., additional, Meng, J., additional, Zhang, S.Q., additional, Jones, P., additional, Wyngaardt, S.M., additional, Jia, H., additional, Chen, Q.B., additional, Li, Z.Q., additional, Wang, S., additional, Sun, D.P., additional, Guo, R.J., additional, Han, X.C., additional, Xu, W.Z., additional, Xiao, X., additional, Zhu, P.Y., additional, Li, H.W., additional, Hua, H., additional, Li, X.Q., additional, Li, C.G., additional, Han, R., additional, Sun, B.H., additional, Zhu, L.H., additional, Bucher, T.D., additional, Kheswa, B.V., additional, Khumalo, N., additional, Lawrie, E.A., additional, Lawrie, J.J., additional, Malatji, K.L., additional, Msebi, L., additional, Ndayishimye, J., additional, Sharpey-Schafer, J.F., additional, Shirinda, O., additional, Wiedeking, M., additional, Dinoko, T., additional, and Ntshangase, S.S., additional
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- 2022
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7. Strong enhancement of level densities in the crossover from spherical to deformed neodymium isotopes
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Guttormsen, M., Alhassid, Y., Ryssens, W., Ay, K.O., Ozgur, M., Algin, E., Larsen, A.C., Bello Garrote, F.L., Crespo Campo, L., Dahl-Jacobsen, T., Görgen, A., Hagen, T.W., Ingeberg, V.W., Kheswa, B.V., Klintefjord, M., Midtbø, J.E., Modamio, V., Renstrøm, T., Sahin, E., Siem, S., Tveten, G.M., and Zeiser, F.
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- 2021
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8. Resonances in odd-odd 182Ta
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Brits C.P., Wiedeking M., Bello Garrote F.L., Bleuel D.L., Giacoppo F., Görgen A., Guttormsen M., Hadynska-Klek K., Hagen T.W., Ingeberg V.W., Kheswa B.V., Klintefjord M., Larsen A.C., Malatji K.L., Nyhus H.T., Papka P., Renstrøm T., Rose S., Sahin E., Siem S., Tveten G.M., and Zeiser F.
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Physics ,QC1-999 - Abstract
Enhanced γ-decay on the tail of the giant electric dipole resonance, such as the scissors or pygmy resonances, can have significant impact on (n,γ) reaction rates. These rates are important input for modeling processes that take place in astrophysical environments and nuclear reactors. Recent results from the University of Oslo indicate the existence of a significant enhancement in the photon strength function for nuclei in the actinide region due to the scissors resonance. Further, the M1 strength distribution of the scissors resonances in rare earth nuclei has been studied extensively over the years. To investigate the evolution and persistence of the scissor resonance in other mass regions, an experiment was performed utilizing the NaI(Tl) γ-ray detector array (CACTUS) and silicon particle telescopes (SiRi) at the University of Oslo Cyclotron laboratory. Particle-γ coincidences from the 181Ta(d,p)182Ta and 181Ta(d,d')181Ta reactions were used to measure the nuclear level density and photon strength function of the well-deformed 181Ta and 182Ta systems, to investigate the existence of resonances below the neutron separation energy.
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- 2017
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9. Nuclear level densities and γ-ray strength functions of 180,181Ta and neutron capture cross sections
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Malatji K.L., Kheswa B.V., Wiedeking M., Bello Garrote F.L., Brits C.P., Bleuel D.L., Giacoppo F., Görgen A., Guttormsen M., Hadynska-Klek K., Hagen T.W., Ingeberg V.W., Klintefjord M., Larsen A.C., Nyhus H.T., Renstrøm T., Rose S., Sahin E., Siem S., Tveten G.M., and Zeiser F.
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Physics ,QC1-999 - Abstract
The γ-ray strength functions and nuclear level densities in the quasi-continuum of 180,181Ta are extracted from particle-γ coincidence events with the Oslo Method, below the Sn. The data were used as input in the TALYS reaction code for calculations of the astrophysical Maxwellian-averaged (n,γ) cross-sections to investigate nucleosynthesis of nature's rarest stable isotope 180Ta.
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- 2017
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10. Statistical gamma-ray decay studies at iThemba LABS
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Wiedeking M., Bernstein L.A., Bleuel D.L., Brits C.P., Sowazi K., Görgen A., Goldblum B.L., Guttormsen M., Kheswa B.V., Larsen A.C., Majola S.N.T., Malatji K.L., Negi D., Nogwanya T., Siem S., and Zikhali B.R.
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Physics ,QC1-999 - Abstract
A program to study the γ-ray decay from the region of high-level density has been established at iThemba LABS, where a high-resolution gamma-ray detector array is used in conjunction with silicon particle-telescopes. Results from two recent projects are presented: 1) The 74Ge(α,α′γ) reaction was used to investigate the Pygmy Dipole Resonance. The results were compared to (γ,γ′) data and indicate that the dipole states split into mixed isospin and relatively pure isovector excitations. 2) Data from the 95Mo(d,p) reaction were used to develop a novel method for the determination of spins for low-lying discrete levels utilizing statistical γ-ray decay in the vicinity of the neutron separation energy. These results provide insight into the competition of (γ,n) and (γ,γ′) reactions and highlights the need to correct for angular momentum barrier effects.
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- 2017
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11. Statistical properties of the well deformed Sm 153,155 nuclei and the scissors resonance
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Malatji, K.L., Beckmann, K.S., Wiedeking, M., Siem, Sunniva, Goriely, Stéphane, Larsen, Anne Cecilie, Ay, K.O., Bello Garrote, Frank Leonel, Campo, Crespo L.C., Görgen, Andreas, Guttormsen, Magne, Ingeberg, V. W., Jones, P., Kheswa, B.V., Von Neumann-Cosel, Peter, Ozgur, Mustafa, Potel, Gregory, Pellegri, Luna, Renstrøm, Therese, Tveten, G.M., and Zeiser, Fabio
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Généralités - Abstract
The nuclear level densities (NLDs) and the γ-ray strength functions (γSFs) of Sm153,155 have been extracted from (d,pγ) coincidences using the Oslo method. The experimental NLD of Sm153 is higher than the NLD of Sm155, in accordance with microscopic calculations. The γSFs of Sm153,155 are in fair agreement with QRPA calculations based on the D1M Gogny interaction. An enhancement is observed in the γSF for both Sm153,155 nuclei around 3 MeV in excitation energy and is attributed to the M1 scissors resonance (SR). Their integrated strengths were found to be in the range 1.3-2.1 and 4.4-6.4 μN2 for Sm153 and Sm155, respectively. The strength of the SR for Sm155 is comparable to those for deformed even-even Sm isotopes from nuclear resonance fluorescence measurements, while that of Sm153 is lower than expected., SCOPUS: ar.j, info:eu-repo/semantics/published
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- 2021
12. First candidates for $\gamma$ vibrational bands built on the $[505]11/{2}^{-}$ neutron orbital in odd-$A$ Dy isotopes
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MAJOLA, S.N.T., SITHOLE, M.A., MDLETSHE, L., HARTLEY, D., TIMÁR, J., NYAKÓ, B.M., ALLMOND, J.M., BARK, R.A., BEAUSANG, C., BIANCO, L., BUCHER, T.D., BVUMBI, S.P., CARPENTER, M.P., CHIARA, C.J., COOPER, N., CULLEN, D.M., CURIEN, D., DINOKO, T.S., GALL, B.J.P., GARRETT, P.E., GREENLEES, P.T., HIRVONEN, J., JAKOBSSON, U., JONES, P.M., JULIN, R., JUUTINEN, S., KETELHUT, S., KHESWA, B.V., KONDEV, F.G., KORICHI, A., KULP, W.D., LAURITSEN, T., LAWRIE, E.A., MAKHATHINI, L., MASITENG, P.L., MAQABUKA, B., MCCUTCHAN, E.A., MILLER, D., MILLER, S., MINKOVA, A., MSEBI, L., MTHEMBU, S.H., NDAYISHIMYE, J., NIEMINEN, P., NGCOBO, P.Z., NTSHANGASE, S.S., ORCE, J.N., PEURA, P., RAHKILA, P., REDON, N., RIEDINGER, L.L., RILEY, M.A., ROUX, D.G., RUOTSALAINEN, P., PIOT, J., SAREN, J., SHARPEY-SCHAFER, J.F., SCHOLEY, C., SHIRINDA, O., SIMPSON, J., SORRI, J., STEFANESCU, I., STOLZE, S., UUSITALO, J., WANG, X., WERNER, V., WOOD, J.L., YU, C.H., ZHU, S., ZIMBA, G., Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
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Nuclear Theory ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Nuclear Structure ,Nuclear Experiment - Abstract
Rotational structures have been measured using the Jurogam II and GAMMASPHERE arrays at low spin following the 155Gd({\alpha},2n)157Dy and 148Nd(12C, 5n)155Dy reactions at 25 and 65 MeV, respectively. We report high-K bands, which are conjectured to be the first candidates of a K{\pi}= 2+ {\gamma} vibrational band, built on the [505]11/2- neutron orbital, in both odd-A 155, 157Dy isotopes. The coupling of the first excited K=0+ states or the so-called \b{eta} vibrational bands at 661 and 676 keV in 154Dy and 156Dy to the [505]11/2- orbital, to produce a K{\pi}=11/2- band, was not observed in both 155Dy and 157Dy, respectively. The implication of these findings on the interpretation of the first excited 0+ states in the core nuclei 154Dy and 156Dy are also discussed., Comment: Published in Physical Rev C
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- 2020
13. Re-estimation of 180Ta nucleosynthesis in light of newly constrained reaction rates
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Malatji, K.L., Wiedeking, M., Goriely, S., Brits, C.P., Kheswa, B.V., Bello Garrote, F.L., Bleuel, D.L., Giacoppo, F., Görgen, A., Guttormsen, M., Hadynska-Klek, K., Hagen, T.W., Ingeberg, V.W., Klintefjord, M., Larsen, A.C., Papka, P., Renstrøm, T., Sahin, E., Siem, S., Siess, L., Tveten, G.M., and Zeiser, F.
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- 2019
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14. Nuclear level densities and γ -ray strength functions of Ta 180,181,182
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Brits, C.P., Malatji, K.L., Wiedeking, M., Kheswa, B.V., Goriely, Stéphane, Garrote, F.L.B., Bleuel, Darren D.L., Giacoppo, Francesca, Görgen, Andreas, Guttormsen, Magne, Hadynska-Klek, K., Hagen, T.W., Hilaire, Stéphane, Ingeberg, V. W., Jia, H., Klintefjord, Malin, Larsen, Ann-Cecilie, Majola, Siyabonga S.N.T., Papka, Paul, Péru, S., Qi, Bin, Renstrøm, Therese, Rose, S.J., Sahin, Esin, Siem, Sunniva, Tveten, G.M., and Zeiser, Fabio
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Généralités - Abstract
Particle-γ coincidence experiments were performed at the Oslo Cyclotron Laboratory with the Ta181(d,X) and Ta181(He3,X) reactions to measure the nuclear level densities (NLDs) and γ-ray strength functions (γSFs) of Ta180,181,182 using the Oslo method. The back-shifted Fermi-gas, constant temperature plus Fermi gas, and Hartree-Fock-Bogoliubov plus combinatorial models were used for the absolute normalizations of the experimental NLDs at the neutron separation energies. The NLDs and γSFs are used to calculate the corresponding Ta181(n,γ) cross sections and these are compared to results from other techniques. The energy region of the scissors resonance strength is investigated and from the data and comparison to prior work it is concluded that the scissors strength splits into two distinct parts. This splitting may allow for the determination of triaxiality and a γ deformation of 14.9 ±1.8 was determined for Ta181., SCOPUS: ar.j, info:eu-repo/semantics/published
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- 2019
15. Re-estimation of Ta nucleosynthesis in light of newly constrained reaction rates
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Malatji, K.L., Wiedeking, M., Goriely, S., Brits, C.P., Kheswa, B.V., Bello Garrote, F.L., Bleuel, D.L., Giacoppo, F., Görgen, A., Guttormsen, M., Hadynska-Klek, K., Hagen, T.W., Ingeberg, V.W., Klintefjord, M., Larsen, A.C., Papka, P., Renstrøm, T., Sahin, E., Siem, S., Siess, L., Tveten, G.M., and Zeiser, F.
- Abstract
Recent measurements of the nuclear level densities and γ-ray strength functions below the neutron thresholds in $^{180,181,182}$Ta are used as input in the nuclear reaction code TALYS. These experimental average quantities are utilized in the calculations of the $^{179,180,181}$Ta radiative neutron capture cross sections. From the latter, astrophysical Maxwellian-averaged (n,γ) cross sections (MACS) and reaction rates are extracted, which in turn are used in large astrophysical network calculations to probe the production mechanism of $^{180}$Ta. These calculations are performed for two scenarios, the s-process production of $^{180,181}$Ta in Asymptotic Giant Branch (AGB) stars and the p-process nucleosynthesis of Tam180 in Type-II supernovae. Based on the results from this work, the s-process in stellar evolution is considered negligible in the production of Tam180 whereas $^{181}$Ta is partially produced by AGB stars. The new measurements strongly constrain the production and destruction rates of Tam180 at p-process temperatures and confirm significant production of nature's rarest stable isotope Tam180 by the p-process.
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- 2019
16. Spectroscopy of low-spin states in $^{157}\mathrm{Dy}$: Search for evidence of enhanced octupole correlations
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Majola, S.N.T., Bark, R.A., Bianco, L., Bucher, T.D., Bvumbi, S.P., Cullen, D.M., Garrett, P.E., Greenlees, P.T., Hartley, D., Hirvonen, J., Jakobsson, U., Jones, P.M., Julin, R., Juutinen, S., Ketelhut, S., Kheswa, B.V., Korichi, A., Lawrie, E.A., Masiteng, P.L., Maqabuka, B., Mdletshe, L., Minkova, A., Ndayishimye, J., Nieminen, P., Newman, R., Nyakó, B.M., Ntshangase, S.S., Peura, P., Rahkila, P., Riedinger, L.L., Riley, M., Roux, D., Ruotsalainen, P., Saren, J., Sharpey-Schafer, J.F., Scholey, C., Shirinda, O., Sithole, A., Sorri, J., Stolze, S., Timár, J., Uusitalo, J., Zimba, G., Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
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Nuclear Theory (nucl-th) ,Nuclear Theory ,nuclear spin and parity ,shell model ,FOS: Physical sciences ,collective levels ,collective models ,Nuclear Experiment (nucl-ex) ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,ydinfysiikka ,Nuclear Structure ,nuclear structure and decays ,Nuclear Experiment - Abstract
Low-spin states of 157Dy have been studied using the JUROGAM II array, following the 155Gd ({\alpha}, 2n) reaction at a beam energy of 25 MeV. The level scheme of 157Dy has been expanded with four new bands. Rotational structures built on the [523]5/2- and [402]3/2+ neutron orbitals constitute new additions to the level scheme as do many of the inter- and intra-band transitions. This manuscript also reports the observation of cross I- to (I-1)- and I- to (I-1)+ E1 dipole transitions inter-linking structures built on the [523]5/2- (band 5) and [402]3/2+ (band 7) neutron orbitals. These interlacing band structures are interpreted as the bands of parity doublets with simplex quantum number s = -i related to possible octupole correlations., Comment: Published in Physical Review C (2019)
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- 2019
17. $\beta$ and $\gamma$ bands in $N=88$, 90, and 92 isotones investigated with a five-dimensional collective Hamiltonian based on covariant density functional theory: Vibrations, shape coexistence, and superdeformation
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Majola, S.N.T., Shi, Z., Song, B.Y., Li, Z.P., Zhang, S.Q., Bark, R.A., Sharpey-Schafer, J.F., Aschman, D.G., Bvumbi, S.P., Bucher, T.D., Cullen, D.M., Dinoko, T.S., Easton, J.E., Erasmus, N., Greenlees, P.T., Hartley, D.J., Hirvonen, J., Korichi, A., Jakobsson, U., Jones, P., Jongile, S., Julin, R., Juutinen, S., Ketelhut, S., Kheswa, B.V., Khumalo, N.A., Lawrie, E.A., Lawrie, J.J., Lindsay, R., Madiba, T.E., Makhathini, L., Maliage, S.M., Maqabuka, B., Malatji, K.L., Masiteng, P.L., Mashita, P.I., Mdletshe, L., Minkova, A., Msebi, L., Mullins, S.M., Ndayishimye, J., Negi, D., Netshiya, A., Newman, R., Ntshangase, S.S., Ntshodu, R., Nyakó, B.M., Papka, P., Peura, P., Rahkila, P., Riedinger, L.L., Riley, M.A., Roux, D.G., Ruotsalainen, P., Saren, J.J., Scholey, C., Shirinda, O., Sithole, M.A., Sorri, J., Stankiewicz, M., Stolze, S., Timár, J., Uusitalo, J., Vymers, P.A., Wiedeking, M., Zimba, G.L., Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
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[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Nuclear Structure - Abstract
International audience; A comprehensive systematic study is made for the collective β and γ bands in even-even isotopes with neutron numbers N=88 to 92 and proton numbers Z=62(Sm) to 70 (Yb). Data, including excitation energies, B(E0) and B(E2) values, and branching ratios from previously published experiments are collated with new data presented for the first time in this study. The experimental data are compared to calculations using a five-dimensional collective Hamiltonian (5DCH) based on the covariant density functional theory (CDFT). A realistic potential in the quadrupole shape parameters V(β,γ) is determined from potential energy surfaces (PES) calculated using the CDFT. The parameters of the 5DCH are fixed and contained within the CDFT. Overall, a satisfactory agreement is found between the data and the calculations. In line with the energy staggering S(I) of the levels in the 2γ+ bands, the potential energy surfaces of the CDFT calculations indicate γ-soft shapes in the N=88 nuclides, which become γ rigid for N=90 and N=92. The nature of the 02+ bands changes with atomic number. In the isotopes of Sm to Dy, they can be understood as β vibrations, but in the Er and Yb isotopes the 02+ bands have wave functions with large components in a triaxial superdeformed minimum. In the vicinity of Sm152, the present calculations predict a soft potential in the β direction but do not find two coexisting minima. This is reminiscent of Sm152 exhibiting an X(5) behavior. The model also predicts that the 03+ bands are of two-phonon nature, having an energy twice that of the 02+ band. This is in contradiction with the data and implies that other excitation modes must be invoked to explain their origin.
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- 2019
18. Nuclear level densities and gamma-ray strength functions of $^{180,181,182}$Ta
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Brits, C.P., Malatji, K.L., Wiedeking, M., Kheswa, B.V., Goriely, S., Garrote, F.L. Bello, Bleuel, D.L., Giacoppo, F., Görgen, A., Guttormsen, M., Hadynska-Klek, K., Hagen, T.W., Hilaire, S., Ingeberg, V.W., Jui, H., Klintefjord, M., Larsen, A.C., Majola, S.N.T., Papka, P., Péru, S., Qi, B., Renstrøm, T., Rose, S.J., Sahin, E., Siem, S., Tveten, G.M., Zeiser, F., Direction des Applications Militaires (DAM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
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Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Nuclear Experiment (nucl-ex) ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Nuclear Structure ,Nuclear Experiment - Abstract
Particle-$\gamma$ coincidence experiments were performed at the Oslo Cyclotron Laboratory with the $^{181}$Ta(d,X) and $^{181}$Ta($^{3}$He,X) reactions, to measure the nuclear level densities (NLDs) and $\gamma$-ray strength functions ($\gamma$SFs) of $^{180, 181, 182}$Ta using the Oslo method. The Back-shifted Fermi-Gas, Constant Temperature plus Fermi Gas, and Hartree-Fock-Bogoliubov plus Combinatorial models where used for the absolute normalisations of the experimental NLDs at the neutron separation energies. The NLDs and $\gamma$SFs are used to calculate the corresponding $^{181}$Ta(n,$\gamma$) cross sections and these are compared to results from other techniques. The energy region of the scissors resonance strength is investigated and from the data and comparison to prior work it is concluded that the scissors strength splits into two distinct parts. This splitting may allow for the determination of triaxiality and a $\gamma$ deformation of $14.9^{\circ} \pm 1.8^{\circ}$ was determined for $^{181}$Ta.
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- 2019
19. Nuclear level densities and γ-ray strength functions of 180,181,182Ta
- Author
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Brits, C.P., Malatji, K.L., Wiedeking, M., Kheswa, B.V., Goriely, Stéphane, Bello Garrote, F.L., Bleuel, D.L., Giacoppo, F, Görgen, Andreas, Guttormsen, Magne, Hadynska-Klek, K., Hagen, T.W., Hilaire, Stéphane, Ingeberg, V. W., Jia, H., Klintefjord, M., Larsen, Ann-Cecilie, Majola, S.N.T., Papka, P., Péru, S., Qi, B., Renstrøm, Therese, Rose, S.J., Sahin, E, Siem, Sunniva, Tveten, G.M., and Zeiser, Fabio
- Subjects
Physique atomique et nucléaire - Abstract
Particle- γ coincidence experiments were performed at the Oslo Cyclotron Laboratory with the 181 Ta ( d , X ) and 181 Ta ( 3 He , X ) reactions to measure the nuclear level densities (NLDs) and γ -ray strength functions ( γ SFs ) of 180 , 181 , 182 Ta using the Oslo method. The back-shifted Fermi-gas, constant temperature plus Fermi gas, and Hartree-Fock-Bogoliubov plus combinatorial models were used for the absolute normalizations of the experimental NLDs at the neutron separation energies. The NLDs and γ SFs are used to calculate the corresponding 181 Ta ( n , γ ) cross sections and these are compared to results from other techniques. The energy region of the scissors resonance strength is investigated and from the data and comparison to prior work it is concluded that the scissors strength splits into two distinct parts. This splitting may allow for the determination of triaxiality and a γ deformation of 14 . 9 ∘ ± 1 . 8 ∘ was determined for 181 Ta .
- Published
- 2019
20. Nuclear level densities and $\gamma$-ray strength functions of $^{87}\mathrm{Kr}$ -- First application of the Oslo Method in inverse kinematics
- Author
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Ingeberg, V.W., Siem, S., Wiedeking, M., Sieja, K., Bleuel, D.L., Brits, C.P., Bucher, T.D., Dinoko, T.S., Easton, J.L., Görgen, A., Guttormsen, M., Jones, P., Kheswa, B.V., Khumalo, N.A., Larsen, A.C., Lawrie, E.A., Lawrie, J.J., Majola, S.N.T., Malatji, K.L., Makhathini, L., Maqabuka, B., Negi, D., Noncolela, S.P., Papka, P., Sahin, E., Schwengner, R., Tveten, G.M., Zeiser, F., Zikhali, B.R., Institut Pluridisciplinaire Hubert Curien (IPHC), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)
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Astrophysics::High Energy Astrophysical Phenomena ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Nuclear Experiment - Abstract
The $\gamma$-ray strength function ($\gamma$SF) and nuclear level density (NLD) have been extracted for the first time from inverse kinematic reactions with the Oslo Method. This novel technique allows measurements of these properties across a wide range of previously inaccessible nuclei. Proton-$\gamma$ coincidence events from the $\mathrm{d}(^{86}\mathrm{Kr}, \mathrm{p}\gamma)^{87}\mathrm{Kr}$ reaction were measured at iThemba LABS and the $\gamma$SF and NLD in $^{87}\mathrm{Kr}$ obtained. The low-energy region of the $\gamma$SF is compared to Shell Model calculations which suggest this region to be dominated by M1 strength. The $\gamma$SF and NLD are used as input parameters to Hauser-Feshbach calculations to constrain $(\mathrm{n},\gamma)$ cross sections of nuclei using the TALYS reaction code. These results are compared to $^{86}\mathrm{Kr}(n,\gamma)$ data from direct measurements., Comment: Submitted to EpJ A Letters
- Published
- 2018
21. Photoneutron cross sections for Ni isotopes: Toward understanding ( n , γ ) cross sections relevant to weak s -process nucleosynthesis
- Author
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Utsunomiya, Hiroaki, Renstrøm, Therese, Tveten, G.M., Goriely, Stéphane, Katayama, S., Ari-Izumi, T., Takenaka, D., Symochko, D., Kheswa, B.V., Ingeberg, V. W., Glodariu, T., Lui, Yiu-Wing, Miyamoto, S., Larsen, Ann-Cecilie, Midtbø, J.E., Görgen, Andreas, Siem, Sunniva, Crespo Campo, L., Guttormsen, Magne, Hilaire, Stéphane, Péru, S., and Koning, Arjan J.
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,Nuclear Theory ,Généralités ,Nuclear Experiment ,Physique atomique et nucléaire - Abstract
Photoneutron cross sections were measured for Ni58,Ni60,Ni61, and Ni64 at energies between the one-neutron and two-neutron thresholds using quasimonochromatic γ-ray beams produced in laser Compton scattering at the NewSUBARU synchrotron radiation facility. These photoneutron data are used to extract the γ-ray strength function above the neutron threshold, complementing the information obtained by the Oslo method below the threshold. We discuss radiative neutron-capture cross sections and the Maxwellian-averaged cross sections for Ni isotopes including Ni63, a branching point nucleus along the weak s-process path. The cross sections are calculated with the experimentally constrained γ-ray strength functions from the Hartree-Fock-Bogolyubov plus quasiparticle-random-phase approximation based on the Gogny D1M interaction for both E1 and M1 components and supplemented with the M1 upbend., SCOPUS: ar.j, info:eu-repo/semantics/published
- Published
- 2018
- Full Text
- View/download PDF
22. Studying the Photon Strength Function of 97Zr Using the 96Zr(n,g) and 96Zr(d,p) Reactions
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Winkelbauer, J., primary, Mosby, S., additional, Couture, A., additional, Lee, H.Y., additional, Kuvin, S., additional, Hoffman, C.R., additional, Ullmann, J., additional, Spyrou, A., additional, Liddick, S.N., additional, Larsen, A.C., additional, Back, B.B., additional, Avila, M.L., additional, Kheswa, B.V., additional, Renstroem, T., additional, Tveten, G., additional, Talwar, R., additional, and Santiago-Gonzales, D., additional
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- 2017
- Full Text
- View/download PDF
23. Galactic production of 138La: Impact of 138,139La statistical properties
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Kheswa, B.V., Wiedeking, M., Giacoppo, F., Goriely, S., Guttormsen, M., Larsen, A.C., Bello Garrote, F.L., Eriksen, T.K., Görgen, A., Hagen, T.W., Koehler, P.E., Klintefjord, M., Nyhus, H.T., Papka, P., Renstrøm, T., Rose, S., Sahin, E., Siem, S., and Tornyi, T.
- Published
- 2015
- Full Text
- View/download PDF
24. Galactic production of 138 La: Impact of 138,139 La statistical properties
- Author
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Kheswa, B.V., primary, Wiedeking, M., additional, Giacoppo, F., additional, Goriely, S., additional, Guttormsen, M., additional, Larsen, A.C., additional, Bello Garrote, F.L., additional, Eriksen, T.K., additional, Görgen, A., additional, Hagen, T.W., additional, Koehler, P.E., additional, Klintefjord, M., additional, Nyhus, H.T., additional, Papka, P., additional, Renstrøm, T., additional, Rose, S., additional, Sahin, E., additional, Siem, S., additional, and Tornyi, T., additional
- Published
- 2015
- Full Text
- View/download PDF
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