Y. Tameshige

Extraction of weak transition strengths via the (He-3, t) reaction at 420 MeV

Differential cross sections for transitions of known weak strength were measured with the (3He, t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn, and 208Pb. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

Nuclear structure relevant to neutrinoless double β decay: The valence protons in Ge76 and Se76

The possibility of observing neutrinoless double {beta} decay offers the opportunity of determining the effective neutrino mass if the nuclear matrix element were known. Theoretical calculations are uncertain, and the occupation of valence orbits by nucleons active in the decay is likely to be important. The occupation of valence proton orbits in the ground states of {sup 76}Ge, a candidate for such decay, and {sup 76}Se, the corresponding daughter nucleus, is determined by precisely measuring cross sections for proton-removing transfer reactions. As in previous work on neutron occupation, we find that the Fermi surface for protons is much more diffuse than previously thought, and the occupancies of at least three orbits change significantly between the two 0{sup +} ground states.

Spectroscopy of 24 Al and extraction of Gamow-Teller strengths with the 24 Mg( 3 He,t) reaction at 420 MeV.

The {sup 24}Mg({sup 3}He,t){sup 24}Al reaction was studied at E({sup 3}He)=420 MeV. An energy resolution of 35 keV was achieved. Gamow-Teller strengths to discrete levels in {sup 24}Al were extracted by using a recently developed empirical relationship for the proportionality between Gamow-Teller strengths and differential cross sections at zero momentum transfer. Except for small discrepancies for a few weak excitations, good agreement with previous {sup 24}Mg(p,n) data and nuclear-structure calculations using the USDA/B interactions in the sd shell-model space was found. The excitation energy of several levels in {sup 24}Al of significance for determination of the {sup 23}Mg(p,{gamma}){sup 24}Al thermonuclear reaction rate were measured. Results are consistent with two of the three previous ({sup 3}He,t) measurements, performed at much lower beam energies. However, a new state at E{sub x}({sup 24}Al)=2.605(10) MeV was found and is the third state above the proton separation energy.

Nuclear structure relevant to neutrinoless double {beta} decay: The valence protons in {sup 76}Ge and {sup 76}Se

The possibility of observing neutrinoless double {beta} decay offers the opportunity of determining the effective neutrino mass if the nuclear matrix element were known. Theoretical calculations are uncertain, and the occupation of valence orbits by nucleons active in the decay is likely to be important. The occupation of valence proton orbits in the ground states of {sup 76}Ge, a candidate for such decay, and {sup 76}Se, the corresponding daughter nucleus, is determined by precisely measuring cross sections for proton-removing transfer reactions. As in previous work on neutron occupation, we find that the Fermi surface for protons is much more diffuse than previously thought, and the occupancies of at least three orbits change significantly between the two 0{sup +} ground states.

Cluster states in 13C

Cross sections for 13C(α,α′) reactions at Eα = 400 MeV have been measured to obtain the monopole and quadrupole transition strengths. The excitation strengths are compared with the shell-model predictions. It is suggested that the large monopole strengths observed for the

Shielding study at the Fukui Prefectural Hospital Proton Therapy Center

1/2^-_2

High-resolution study of the Be-9(He-3,t) B-9 reaction up to the B-9 triton threshold

and

Complete Set of Polarization Transfer Observables for the 12C( p,n) Reaction at 296 MeV and 0°

1/2^-_3

Evaluation of Focal Liver Reaction after Proton Beam Therapy for Hepatocellular Carcinoma Examined Using Gd-EOB-DTPA Enhanced Hepatic Magnetic Resonance Imaging

states in 13C are attributed to the cluster structure of those states.

Cross-sections and analyzing powers for

At the Fukui Prefectural Hospital Proton Therapy Center, neutron doses behind the concrete shields and at the maze were measured with three types of radiation monitors (DARWIN, Wendi-2, and a rem meter) along with solid-state nuclear track detectors. The measured data were compared with estimations of analytical models and the Monte Carlo code, Particle and Heavy-Ion Transport code System (PHITS). The analytical model, using the parameters employed in the shielding design of the facility, gave considerably larger values than the measured data. This means that the facility was designed with a sufficient margin of safety. The results calculated by PHITS were less than those of the analytical model and were about three times larger than the measured data. From a perspective that seeks conservative estimation with less margin, the Monte Carlo simulation is a good tool for shielding design of accelerator-based proton treatment facilities.