We have developed a new experimental technique to determine the gamma emission probability from unbound states populated by the (d, p) reaction at 20 MeV/nucleon under the inverse kinematics. This was achieved using the decelerating and focusing device OEDO at RIBF. Due to the inverse kinematics, the outgoing reaction residues can be identified by a magnetic spectrometer. By combining the missing spectroscopy with the identification of the residual ions, the γ emission channel was determined event-by-event as a function of the excitation energy, without detecting γ ray from the unbound states. As the first application, the method was used to study the neutron capture reaction on 79 Se via the (d, p) reaction as a surrogate reaction for the neutron energies up to 5 MeV. Additionally, the technique was employed to investigate the compound reaction channel of (n, γ) cross sections on 130 Sn.

Nuclear transmutation is emerging as a promising approach for reprocessing high-level waste, specifically treating long-lived nuclides like Zr-93 from spent fuel. It is essential to accumulate reaction data for these nuclei to advance this prominent treatment and to build a comprehensive understanding of reaction mechanisms. In this study, the residual production cross-sections resulting from proton-induced reactions on Zr-93 were measured at 27 MeV/nucleon in inverse kinematics. At the RI Beam Factory (RIBF), the Optimized Energy Degrading Optics beamline was used to deduce production cross-sections for isotopes Nb91-93, Zr-91,Zr-92, and Y-88,Y-89. Comparing the results from this study and prior research with calculated excitation functions, a moderate agreement is found with theoretical predictions derived from TALYS and CCONE. The measured cross-sections offer valuable insights for future considerations in nuclear-waste treatment facilities. This is particularly relevant for facilities exploring innovative methods, such as accelerator-driven systems.

The deuteron is a loosely bound system that can easily break up into its constituent proton and neutron whilst in the presence of Coulomb and nuclear fields. Previous experimental studies have shown that this breakup process has a significant impact on residual-nucleus production from deuteron bombardment in the high-energy range of 50-210 MeV/nucleon. However, there remains a lack of cross-section data at energies below 50 MeV/nucleon. The current study determined Zr-93 + d reaction cross sections under inverse kinematics at approximately 28 MeV/nucleon using the BigRIPS separator, OEDO beamline, and SHARAQ spectrometer. Cross sections from this research were compared with previous measurements and theoretical calculations. The experimental results show a large enhancement of the production cross sections of residual nuclei, especially those produced from a small number of particle emissions, compared to the proton-induced reaction data at similar bombarding energy. The DEURACS calculation, which quantitatively takes deuteron-breakup effects into account, reproduces the data well. As a long-lived fission product, Zr-93 remains a challenge for nuclear-waste disposal and treatment. This study's low-energy data may assist future consideration of nuclear-waste treatment facilities, where Zr-93 + d may feasibly transmute the waste into short-lived/stable nuclei.

Spallation reaction for the long-lived fission product 107 Pd has been studied for the purpose of nuclear waste transmutation. The isotopic-distribution cross sections on both proton and deuteron were obtained at 118 MeV/nucleon in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. A large cross-section difference was found between the proton and deuteron results for the light-mass products. The data were compared with the SPACS semi-empirical parameterization and the PHITS calculations including both the intranuclear cascade and evaporation processes. In addition, the potential of spallation reaction for transmutation of 107 Pd is discussed.

The isotope-production cross sections in p- and d-induced reactions on 93Zr at approximately 50 MeV/nucleon were measured by using the inverse-kinematics method at RIKEN RI Beam Factory. The measured data were compared with the previous experimental 93Zr + p, d at 105 and 209 MeV/nucleon data. This comparison represents that the isotopic distribution of production cross sections at 51 MeV p-induced reaction is appreciably different from those at 105 and 209 MeV. On the other hand, these three data sets show that the shape of isotopic distribution is similar in the case of the d-induced reaction. Also, the measured production cross sections were compared with the theoretical model calculations with Particle and Heavy Ion Transport code System (PHITS) version 3.10 in order to investigate the reproducibility of the models implemented in PHITS. The calculations well reproduced the experimental data even in such low incident energy, while several discrepancies were still seen as in the p- and d-induced reactions at 105 and 209 MeV/nucleon.

Coulomb breakup reactions of Zr have been studied in inverse kinematics at incident beam energies of about 200 MeV/nucleon in order to evaluate neutron capture reaction methods. The Zr(n,)Zr reaction is particularly important as a candidate nuclear transmutation reaction for the long-lived fission product Zr in nuclear power plants. One- and two-neutron removal cross sections on Pb and C targets were measured to deduce the inclusive Coulomb breakup cross sections, 375 29 (stat.) 30 (syst.) and 403 26 (stat.) 31 (syst.) mb for Zr and Zr, respectively. The results are compared with estimates using the standard Lorentzian model and microscopic calculations. The results reveal a possible contribution of the pygmy dipole resonance or giant quadrupole resonance in the Coulomb breakup reactions of Zr.

The Optimized Energy Degrading Optics (OEDO) beamline is an upgrade of the High-resolution beamline at the RI Beam Factory at RIKEN. Its purpose is to measure nuclear reactions induced by radioactive ions at 10-50 MeV/u. The main components of the OEDO beamline are two superconducting quadrupole triplet magnets and one radio-frequency deflector, which were recently installed. This setup produces slowed-down, well-focused radioactive-isotope beams by using a degree of freedom in the longitudinal phase space of the beam. This paper describes the OEDO beamline in detail, discusses the unique concept of its ion optics, and demonstrates its feasibility by conducting measurements with medium-mass radioactive-isotope beams.

Isotope-production cross sections for p-, d-, and C-induced spallation reactions on Nb-93 at 113 MeV/nucleon were measured using the inverse-kinematics method employing secondary targets of CH2, CD2, and C. The measured cross sections for Mo-90, Nb-90, (86)'Y-88 produced by p-induced reactions were found to be consistent with those measured by the conventional activation method. We performed benchmark tests of the reaction models INCL-4.6, JQMD, and JQMD-2.0 implemented in the Particle and Heavy Ion Transport code System (PHITS) and of the nuclear data libraries JENDL-4.0/HE, TENDL-2017, and ENDF/B-VIII.O. The model calculations also showed generally good agreement with the measured isotope-production cross sections for p-, d-, and C-induced reactions. It also turns out that, among the three nuclear data libraries, JENDL-4.0/HE provides the best agreement with the measured data for the p-induced reactions. We compared the present Nb-93 data with the Zr-93 data, that were measured previously by the same inverse kinematics method (Kawase et al., Prog. Theor. Exp. Phys. 2017, 093D03 (2017)), with particular attention to the effect of neutron-shell closure on isotope production in p- and d-induced spallation reactions. The isotopic distributions of the measured production cross sections in the Zr-93 data showed noticeable jumps at neutron number N = 50 in the isotopic chains of Delta Z = 0 and -1, whereas no such jump appeared in isotopic chain of Delta Z = 0 in the Nb-93 data. From INCL-4.6 + GEM calculations, we found that the jump formed in the evaporation process is smeared out by the intranuclear cascade component in 91 Nb produced by the Nb-93(p, p2n) and (d, d2n) reactions on Nb-93. Moreover, for Nb-93, the distribution of the element-production cross sections as a function of the change in proton number Delta Z is shifted to smaller Delta Z than for( 93)Zr, because the excited Nb prefragments generated by the cascade process are more likely to emit protons than the excited Zr prefragments, due to the smaller proton-separation energies of the Nb isotopes.

J-PARC E40 aims to measure the differential cross sections of the Σ^±p elastic scatterings and the Σ^−p → Λn conversion. A clear peak of Σ^− was observed in a missing mass spectrum of the π^−p → K^+X reaction and recoil protons from the πp elastic scattering were successfully observed in the data taken in the summer 2018. The rest of data taking is coming in the spring 2019.

S. B. Yang, 2, ∗ J. K. Ahn, Y. Akazawa, K. Aoki, N. Chiga, H. Ekawa, P. Evtoukhovitch, A. Feliciello, M. Fujita, S. Hasegawa, S. Hayakawa, T. Hayakawa, R. Honda, K. Hosomi, S. H. Hwang, N. Ichige, Y. Ichikawa, M. Ikeda, K. Imai, S. Ishimoto, S. Kanatsuki, S. H. Kim, S. Kinbara, K. Kobayashi, T. Koike, J. Y. Lee, K. Miwa, T. J. Moon, T. Nagae, Y. Nakada, M. Nakagawa, Y. Ogura, A. Sakaguchi, H. Sako, Y. Sasaki, S. Sato, K. Shirotori, H. Sugimura, S. Suto, S. Suzuki, T. Takahashi, H. Tamura, K. Tanida, Y. Togawa, Z. Tsamalaidze, M. Ukai, T. F. Wang, and T. O. Yamamoto

This department welcomes brief communications reporting new demonstrations, laboratory equipment, techniques, or materials of interest to teachers of physics. Notes on new applications of older apparatus, measurements supplementing data supplied by manufacturers, information which, while not new, is not generally known, procurement information, and news about apparatus under development may be suitable for publication in this section. Neither the American Journal of Physics nor the Editors assume responsibility for the correctness of the information presented. Manuscripts should be submitted using the web-based system that can be accessed via the American Journal of Physics home page, http://ajp.dickinson.edu and will be forwarded to the ADN editor for consideration.

Spallation reactions for the long-lived fission products 137Cs, 90Sr and 107Pd have been studied for the purpose of nuclear waste transmutation. The cross sections on the proton- and deuteron-induced spallation were obtained in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. Both the target and energy dependences of cross sections have been investigated systematically. and the cross-section differences between the proton and deuteron are found to be larger for lighter fragments. The experimental data are compared with the SPACS semi-empirical parameterization and the PHITS calculations including both the intra-nuclear cascade and evaporation processes.

Spallation reactions for the long-lived fission products Cs-137, Sr-90 and Pd-107 have been studied for the purpose of nuclear waste transmutation. The cross sections on the proton- and deuteron-induced spallation were obtained in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. Both the target and energy dependences of cross sections have been investigated systematically. and the cross-section differences between the proton and deuteron are found to be larger for lighter fragments. The experimental data are compared with the SPACS semi-empirical parameterization and the PHITS calculations including both the intra-nuclear cascade and evaporation processes.

Isotopic production cross sections were measured for proton- and deuteron-induced reactions on 93Nb by means of the inverse kinematics method at RIKEN Radioactive Isotope Beam Factory. The measured production cross sections of residual nuclei in the reaction 93Nb + p at 113 MeV/u were compared with previous data measured by the conventional activation method in the proton energy range between 46 and 249 MeV. The present inverse kinematics data of four reaction products (90Mo, 90Nb, 88Y, and 86Y) were in good agreement with the data of activation measurement. Also, the model calculations with PHITS describing the intra-nuclear cascade and evaporation processes generally well reproduced the measured isotopic production cross sections.

Spallation reactions for the long-lived fission product Zr-93 have been studied in order to provide basic data necessary for nuclear waste transmutation. Isotopic-production cross sections via proton-and deuteron-induced spallation reactions on Zr-93 at 105 MeV/nucleon were measured in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. Remarkable jumps in isotopic production originating from the neutron magic number N = 50 were observed in Zr and Y isotopes. The experimental results were compared to the PHITS calculations considering both the intranuclear cascade and evaporation processes, and the calculations greatly overestimated the measured production yield, corresponding to few-nucleon-removal reactions. The present data suggest that the spallation reaction is a potential candidate for the treatment of Zr-93 in spent nuclear fuel.

Spallation reaction study has been performed for the long-lived fission products 137Cs, 90Sr and 107Pd. Isotopic cross sections on proton and deuteron were obtained by using the inverse kinematics technique at the RIKEN Radioactive Isotope Beam Factory. It was found that the deuteron-induced cross sections are larger than the proton-induced ones for the light-mass products. The experimental data were compared with the SPACS semi-empirical parameterization and a theoretical calculation including both the intra-nuclear cascade and evaporation models by the PHITS transport code. It was found that the spallation reaction could be a promising mechanism for the transmutation of 137Cs and 90Sr due to the large total cross section.