Bulletin of the American Physical Society
2020 Fall Meeting of the APS Division of Nuclear Physics
Volume 65, Number 12
Thursday–Sunday, October 29–November 1 2020; Time Zone: Central Time, USA
Session KE: Nuclear Reactions: Heavy-Ions/Rare isotope Beams I |
Hide Abstracts |
Chair: Kaitlin Cook, Mich St. U. |
Saturday, October 31, 2020 8:30AM - 8:42AM |
KE.00001: Capture cross sections for 50Ti induced reactions with heavy nuclei Walter Loveland, Larry Yao, Ricardo Yanez, Vishal Desai, Ashley Pica, Daniel Santiago-Gonzalez, Birger Back, John Greene Fission fragment angular distributions have been measured for the interaction of 50Ti with 197Au, 235U and 248Cm. Capture-fission cross sections have been deduced from these angular distributions. These cross sections are compared to previous measurements of capture cross sections for 50Ti reactions and modern theoretical calculations, including phenomenological models such as PACE IV, HIVAP and the Langevin model of Zagrebaev and Greiner. The predictions of these models differ from each other and the data by large factors (2-10x). Quantitative suggestions for the synthesis of heavy nuclei using a 50Ti projectile are made. [Preview Abstract] |
Saturday, October 31, 2020 8:42AM - 8:54AM |
KE.00002: Nuclear matter properties at the scission points during quasi- and fusion-fission processes S. Zhu, K. Zhao, R. V. F. Janssens, J Becker, M. P. Carpenter, D. Cline, A. Gade, A. B. Hayes, T. Lauritsen, E. A. McCutchan, D. Seweryniak, A. A. Sonzogni, X. Wang, C. Y. Wu The angular correlations of complementary fragments produced in the reaction of a $^{48}$Ca beam (285 MeV) on a $^{208}$Pb target (1mg/cm$^{2}$) were measured with the CHICO detector at ATLAS. The deep-inelastic and fission (quasi-fission and fusion-fission) reaction products can be separated by their respective behavior in the angular correlation of the fragments. The results have been simulated with the Improved Quantum Molecular Dynamics (ImQMD) model. It is found that the angular correlations are sensitive to the properties of nuclear matter in quasi- and fusion-fission reactions, but not in deep-inelastic processes. The data are reproduced more satisfactorily by calculations with a nuclear saturation density $\rho_0$=0.13 fm$^{-3}$ and a corresponding incompressibility for infinite nuclear matter of K$_\infty$=260 MeV, which are noticeably different from the generally-adopted values of $\rho_0$=0.16 fm$^{-3}$ and K$_\infty$=230 MeV. This indicates that the deformation at the sission point is larger during fission. [Preview Abstract] |
Saturday, October 31, 2020 8:54AM - 9:06AM |
KE.00003: Energy Dependence of Fission Product Yields Matthew Gooden, Todd Bredeweg, Jerry Wilhelmy, Anthony Ramirez, Anton Tonchev, Jack Silano, Mark Stoyer, Sean Finch, Werner Tornow Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, $^{\mathrm{235}}$U, $^{\mathrm{238}}$U and $^{\mathrm{239}}$Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and $\gamma $-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6 and 14.8 MeV. New data in the second chance fission region of 5.5 -- 11 MeV are included to complete the measurements in the energy range of interest. These results are compared to previous measurements and theoretical estimates. [Preview Abstract] |
Saturday, October 31, 2020 9:06AM - 9:18AM |
KE.00004: Probing the Asymmetry Dependence of the Nuclear Caloric Curve in Fusion-Evaporation Reactions Alan B. McIntosh, Lauren A. McIntosh, Kris Hagel, Sherry J. Yennello The nuclear caloric curve, the relation between temperature and excitation, is an emergent property of the nuclear equation of state. Some theoretical models predict the caloric curve depends on the neutron excess, but the magnitude and even sign of this dependence varies between models. We aim to characterize the asymmetry dependence of the nuclear caloric curve experimentally. Since the caloric curve emerges from the microscopic interaction, knowledge of the asymmetry dependence of the caloric curve may constrain the asymmetry energy in the nuclear equation of state. Our previous experimental measurement, using multi-fragmentation reactions, has shown that the nuclear caloric curve shifts to lower temperatures as the system becomes more neutron rich. We have conducted an experiment to study this effect in an independent way, using fusion-evaporation reactions of 78,86Kr + 12C @ 15, 25, 35 MeV/u. Light charged particles were measured to extract the temperature and heavy residues were measured to select on fusion. The experimental setup, calibration, and analysis of nuclear temperatures in the fusion reactions will be discussed. [Preview Abstract] |
Saturday, October 31, 2020 9:18AM - 9:30AM |
KE.00005: Benchmarking an Active Catcher Array for the Study of Multinucleon Transfer Reactions A. Hood, J. Gauthier, K. Hagel, A. Jedele, Y.-W. Lui, A. McIntosh, L. McIntosh, Z. Tobin, R. Wada, A. Wakhle, S. Yennello Multinucleon transfer (MNT) reactions may offer a way to produce new neutron-rich isotopes of known and yet-to-be discovered elements in the heavy and super-heavy mass regimes. Despite decades of study, many open questions remain about MNT reactions. For example, the mechanisms of multinucleon transfers in low-energy collisions of very heavy ions are not well understood. Experimental data are imperative to verify and refine theoretical models as well as decide how to proceed experimentally in the future. Many experimental challenges to these studies exist, such as large background and uncertainties in product scattering angle. We have developed an active catcher array which can be used in-beam to study short and long-lived MNT products [1]. Two experiments were conducted to benchmark the functionality of the array. We present the results from these experiments and discuss the next steps we will take to pursue the study of MNT reactions at the Texas A\&M University Cyclotron Institute. [1] Wuenschel, S., et al., PRC 90, 011601 (2014). [Preview Abstract] |
Saturday, October 31, 2020 9:30AM - 9:42AM |
KE.00006: Multinucleon Transfer Reactions in the TDHF Framework Kyle Godbey, Cedric Simenel, Sait Umar At the center of efforts to understand the rapid neutron capture process, the structure of exotic nuclei, and quantum equilibration processes lies the fundamental problem of synthesizing neutron-rich nuclei. Multinucleon transfer (MNT) reactions in particular are well positioned to probe the neutron-rich region and has been the subject of extensive study in recent years. Out of the many approaches available to study MNT reactions, the time-dependent Hartree-Fock (TDHF) method paired with the time-dependent random phase approximation (TDRPA) extension has been used to great effect to reproduce experimental results and as a predictive tool. In this presentation we give an overview of TDHF+TDRPA calculations and their recent application to $^{176}$Yb$+^{176}$Yb symmetric collisions\footnote{K. Godbey, C. Simenel, and A. S. Umar, Phys. Rev. C 101, 034602 (2020)}. Scattering and equilibration features of the system were systematically investigated with a primary goal being to provide experimental guidance and probe the limits of the theoretical approach. The viability of the system as a generator for neutron-rich nuclei is also explored in addition to laying the groundwork for future studies that are possible within this framework. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700