Bulletin of the American Physical Society
6th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Sunday–Friday, November 26–December 1 2023; Hawaii, the Big Island
Session C04: Nuclear Reaction I |
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Chair: Nobu Imai Room: Hilton Waikoloa Village Kings 2 |
Tuesday, November 28, 2023 7:00PM - 7:15PM |
C04.00001: Comparison of the projectile fragmentation reaction in GEANT4 against EPAX formula for rare isotopes studies Sokhna Bineta Lo Amar, Paul Gueye, Thomas Baumann, Oumar Ka The study of unstable nuclei far from β-stability through fragmentation of heavy-ion beams is one of the most used approaches in low to intermediate energy nuclear physics to gain insights into their nuclear structure and the reaction mechanisms. |
Tuesday, November 28, 2023 7:15PM - 7:30PM |
C04.00002: Breakup and Incomplete Fusion Mechanisms of 7Be + 208Pb Reactions Marshall Basson, Kaitlin J Cook, Iulia-Maria Harca, Kyle W Brown Weakly-bound nuclei (e.g. $^{6,7}$Li, $^9$Be) are observed to have up to 35\% suppression of complete fusion compared to single-barrier penetration models when reacting with heavy targets at above-barrier energies [1] [2]. |
Tuesday, November 28, 2023 7:30PM - 7:45PM |
C04.00003: One-neutron removal and reaction cross sections for 16N(0-) isomeric state Mitsunori Fukuda, Miki Fukutome, Masaomi Tanaka, Daiki Nishimura, Maya Takechi, Wataru Horiuchi, Gen Takayama, Ryo Taguchi, Soshi Ishitani, Takashi Ohtsubo, Norihide Noguchi, Kazuya Takatsu, Takuji Izumikawa, Mototsugu Mihara, Kensaku Matsuta, Takeshi Suzuki, Takayuki Yamaguchi, Shinji Sato, Shigekazu Fukuda, Atsushi Kitagawa, Asahi Yano, Hiroyuki Takahashi, Sora Sugawara, Takato Sugisaki The isomeric state of nuclei is a very important subject of study, not only because it is of interest for its peculiar nuclear structure, but also because it can affect nucleosynthesis in the universe. For example, the population of isomeric states in hot stellar interiors can be comparable to that of the ground state, and the capture cross section of a core nucleus for a neutron(proton) is greatly increased if the valence nucleon is in a halo state. We focused on the isomeric state of 16N and performed the following experiments to confirm the possibility that the valence neutron in that state is like a neutron halo. We have already measured the isomer ratios of 16N secondary beams produced by irradiating 160 MeV/u 18O and 169 MeV/u 15N beams on Be targets and found them to be 22% and 8%, respectively. |
Tuesday, November 28, 2023 7:45PM - 8:00PM |
C04.00004: First study of the $^8$Li(t,p)$^{10}$Li and $^{12}$B(t,p)$^{14}$B reactions Alan H Wuosmaa, Daniel G McNeel, Jie Chen, Roderick M Clark, Heather L Crawford, Catherine M Deibel, Calem Hoffman, Robert V Janssens, Benjamin Kay, Sean A Kuvin, Scott T Marley, Augusto Macchiavelli, John P Schiffer, Tsz Leung Tang, David K Sharp, Jeremy W Smith, Gemma L Wilson We report on studies of $^{12}$B(t,p)$^{14}$B and $^8$Li(t,p)$^{10}$Li reactions in inverse kinematics with HELIOS at Argonne National Laboratory. Two-neutron transfer reactions can populate states inaccessible to single-nucleon transfer. States in $^{14}$B and $^{10}$Li with strong sd$^2$ character can provide new information about the about the changing nature of the p-sd splitting in this mass region that is important, for example, in understanding the disappearance of the N=8 shell gap suggested in $^{12}$Be. For the unbound levels, small single-neutron spectroscopic factors for sd$^2$ levels can make these states much narrower than the single-particle states at lower excitation energy. Secondary $^{12}$B and $^8$Li beams produced using the RAISOR separator at the ATLAS facility at Argonne National Laboratory bombarded a $^3$H target consisting of $^3$H adsorbed into a 450 $μ$g/cm$^2$ Ti foil. Protons and recoiling nuclei were detected using silicon-detector arrays in HELIOS. The experimental results will be compared to the predictions of shell-model calculations. |
Tuesday, November 28, 2023 8:00PM - 8:15PM |
C04.00005: Proton- and Deuteron-Induced Reactions on 93Zr in Inverse Kinematics Jongwon W Hwang, Thomas Chillery, Masanori Dozono, Nobuaki Imai, Shin'ichiro Michimasa, Toshiyuki Sumikama, Shinsuke Ota Nuclear reactions occurring at energies of a few tens of MeV per nucleon (MeV/u) are primarily influenced by compound and pre-equilibrium processes. Unlike direct reactions, these processes involve the dissipation of the projectile’s kinetic energy into the target nucleus. Several factors, such as the initial energy and level densities of the nuclides involved in the reaction, can influence the cross sections leading to the formation of final nuclei. The reaction mechanism becomes more complex when considering deuteron-induced reactions, as the loosely bound nature of the deuteron increases the possibility of its break-up near the target. In this study, we conducted measurements of the cross sections for the reactions 93Zr + p and 93Zr + d at approximately 28 MeV/u, employing inverse kinematics with the BigRIPS-OEDO beamline and SHARAQ spectrometer. These measurements were part of the experimental campaign conducted by the ImPACT17-02-01 collaboration. To analyze our experimental results, we compared the production cross sections of each isotope with the theoretical estimations obtained from TALYS and DEURACS codes. Additionally, we examined previous measurements conducted at higher energies. In this presentation, we will provide a comprehensive overview of the experimental methodology, present the results obtained for the reactions 93Zr + p and 93Zr + d, and discuss potential interpretations of the results by comparing them with the theoretical calculations. |
Tuesday, November 28, 2023 8:15PM - 8:30PM |
C04.00006: Coulomb and nuclear breakup reactions of a halo nucleus 31Ne Takashi Nakamura, Takato Tomai, Yosuke Kondo Experimental results on the exclusive Coulomb and nuclear breakup of 31Ne at c.a. 240 MeV/nucleon at RIBF at RIKEN are presented. The experiment used both C and Pb targets, and the emitted 30Ne and the neutron were measured in coincidence using the SAMURAI spectrometer at RIBF. Gamma rays were also measured when 30Ne was produced in any bound excited states. The extracted Coulomb breakup energy spectrum for the Pb target showed a strong peak just above the neutron decay threshold, typical for a halo nucleus, and is consistent with the previous inclusive measurements. A remarkable result was that the decay channel into the first excited state of the 30Ne core plus a neutron has significant cross sections. For the nuclear breakup of 31Ne, in addition to the 31Ne+C results, we also obtained the results for the one proton removal of 32Na and one neutron removal of 32Ne. Combined results have revealed several new resonance states above the one neutron decay threshold of 31Ne. The spectrum is discussed in terms of a deformed halo structure of the island-of-inversion nucleus 31Ne. |
Tuesday, November 28, 2023 8:30PM - 8:45PM |
C04.00007: Spectroscopy of neutron-rich nuclei using re-accelerated beams and direct reactions at TRIUMF Rituparna Kanungo, David G Walter, Mukhwinder Singh, Gurmukh Singh
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Tuesday, November 28, 2023 8:45PM - 9:00PM |
C04.00008: Measurements of Reaction Cross Sections for 12C, 20Ne and 27Al on heavy-mass targets Norihide Noguchi, Maya Takechi, Takashi Ohtsubo, Mitsunori Fukuda, Masaomi Tanaka, Daiki Nishimura, Mototsugu Mihara, Takeshi Suzuki, Takayuki Yamaguchi, Junsei Chiba, Tetsuaki Moriguchi, Takuji Izumikawa, Shinji Sato, Shigekazu Fukuda, Atsushi Kitagawa, Ayaka Ikeda, Hiroyuki Oikawa, Kosuke Ohnishi, Miki Katayama, Ikuma Kato, Yuki Kanke, Naoto Kanda, Yukiya Kobayashi, Sora Sugawara, Takanobu Sugihara, Kazuya Takatsu, Hiroyuki Takahashi, Gen Takayama, Natsuki Tadano, Ryo Taguchi, Yutaro Tanaka, Yuki Tazawa, Kazuya Chikaato, Hang Du, Junya Nagumo, Kenji Nishizuka, Miki Fukutome, Akira Honma, Masahiro Machida, Eri Miyata, Asahi Yano, Shintaro Yamaoka, Kiyoshi Wakayama The reaction cross section (σR) for the atomic nucleus is closely related to the nuclear radius. The method to deduce nuclear radii from the measured σR is based on the Glauber model. The applicability of this method for light-mass nuclei (Z ≤20, A<50, such as 27Al) has been well established with many precise σR data and the Glauber-type calculation in the energy range of 30~400 MeV/nucleon[1]. On the other hand, the applicability to medium- or heavy-mass nuclei has not yet been examined based on the experimental data. The theoretical study predicts the non-negligible contribution of the electromagnetic dissociation (EMD) (e.g. 6% of σR for the Pb + C system)[2]. In this study, we performed σR measurements for the medium and heavy mass regions where there is a lack of data. The σR for 12C, 20Ne, and 27Al on Fe and Pb targets were measured at the beam energies from 70 to 350 MeV/nucleon at the HIMAC (Heavy Ion Medical Accelerator in Chiba) facility. The obtained data were compared to the Glauber-type calculation, allowing us to evaluate the contribution of the EMD effect. |
Tuesday, November 28, 2023 9:00PM - 9:15PM |
C04.00009: 80Ge(d,pγ) Measurements at FRIB to Inform (n,γ) Reaction Rates in Weak r-process Nucleosynthesis Mara M Grinder, Jolie A Cizewski, Steven D Pain, Andrew Ratkiewicz, Kate Jones, Sudarsan Balakrishnan, Kelly A Chipps, Heather I Garland Individual (n,g) rates become important in the weak r-process near Z=26-34 and N=50 during freeze out from a hot r-process, and (n,g) rates for a handful of specific isotopes exhibit notable impacts on final r-process abundance patterns in sensitivity studies. One such nucleus is 80Ge which has an enhanced sensitivity and is in reach for reaction studies at FRIB. The 80Ge(d,pg) reaction will be measured at FRIB using GODDESS and the S800 at 45 MeV/u. This measurement aims to constrain spectroscopic factors for bound states including low-lying ½+-5/2+ doublet, in combination with a previous measurement at ~4 MeV/u, from which direct neutron capture cross sections will be determined. Additionally, the experiment will inform the compound nucleus (n,g) cross sections via the Surrogate Reaction Method. |
Tuesday, November 28, 2023 9:15PM - 9:30PM |
C04.00010: Constraining Neutron Capture Cross Sections via Surrogate Measurements With Hyperion Jes Koros, Anna Simon, Philip Adsley, Orlando Gomez, Jason T Harke, Richard O Hughes, Brett H Isselhardt, Brenden R Longfellow, Miriam Matney, Lauren McIntosh, Craig S Reingold, Antti Saastamoinen, Aaron S Tamashiro, Barbara S Wang Indirect measurements are necessary to constrain the cross sections and reaction rates of nuclear reactions that are inaccessible for direct measurement. One such indirect technique is the surrogate method. This method uses an alternate reaction channel to populate a nucleus of interest, and in-beam γ-ray spectroscopy enables measurement of γ-decay probabilities for very short-lived nuclei. Experimental results are used together with nuclear data as constraints in Hauser-Feshbach calculations. These are statistical nuclear models of the desired and surrogate reactions which use nuclear level densities, optical model potentials, and γ-strength functions (γSF) to predict reaction cross sections. Experimental γ-decay probabilities may be used to constrain the γSF models, and therefore the resulting neutron capture cross section. |
Tuesday, November 28, 2023 9:30PM - 9:45PM |
C04.00011: Production of Np isotopes from 238U beam at BigRIPS Chihaya Fukushima, Riku Matsumura, Daiki Nishimura, Hideaki Otsu, He Wang, Hidetada Baba, Naoki Fukuda, Tadaaki Isobe, Kei Kokubun, Mizuki Kurata-NIshimura, Shinichiro Meigo, Takahiro Nishi, Hiroyoshi Sakurai, Masaki Sasano, Hiromi Sato, Yohei Shimizu, Toshiyuki Sumikama, Hiroshi Suzuki, Hiroyuki Takahashi, Hiroyuki Takeda, Junki Tanaka, Yasuhiro Togano, Koichi Yoshida, Masahiro Yoshimoto A variety of rare isotope beams with atomic numbers (Z) up to 92 can be produced by the projectile fragmentation and in-flight fission from high intensity U beams at RIBF. In numerous instances of spallation reactions, transitions to channels leading to Z+1 have been observed, and their energy dependence can be perceived qualitatively. In the Pd region, a comprehensive investigation was conducted by Wang et al. It was also found that 234−238Np can be generated by a proton pickup reaction at 1 GeV/u 238U beam by E.Casarejos et al. Owing to the developments of the high-Z beams at BigRIPS, energy dependence of the proton pickup reaction on 238U can be obtained at RIBF. Thus, we conducted an experiment to determine the energy dependence of the production cross section of 237Np. |
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