[en] Short note

[en] Measurements of the vector analyzing power iT₁₁ in π⁺d elastic scattering at 50 MeV have been made at pion laboratory scattering angles between 60 degree and 130 degree using a dynamically polarized target and a magnetic spectrometer. In contrast to measurements of spin observables at higher energies, we find agreement with models that include the πN P₁₁ amplitude and disagreement with models that exclude or suppress it

[en] The absolute differential cross section for the ³H(p,γ)⁴He reaction has been measured at θ_γ=90 degree for E_p=2.0--15.0 MeV, corresponding to photon energies E_γ=21.3--31.1 MeV. The present results are 35% lower than previously measured (p,γ) cross sections and are in excellent agreement with recent (γ,p) data obtained with monoenergetic photons. Comparing our results to current photoneutron cross sections gives a ratio σ(γ,p)/σ(γ,n)=1.09±0.17 for E_γ=24--31 MeV. This ratio is consistent with conventional theoretical predictions, indicating that no charge-symmetry violation in ⁴He is required

[en] A recent experiment has measured analyzing powers in d(rvec p,π^-pp)p in a geometry which selected the quasifree two-body reaction rvec pn→π^-pp(¹S₀). Analysis of the results indicated a significant contribution from a very-short-range part of the nucleon-nucleon interaction. We show that the analyzing power data measured in the above experiment is reasonably well described by a unitary NN → NNπ model containing only the one-pion-exchange driving force

[en] Coincident neutron-proton pairs were measured from the reaction ³He(γ,np)p with a 100-MeV bremsstrahlung beam. The energy and angle of the neutron and proton were used to reconstruct the photon energy, making this a kinematically complete experiment. Quasi-deuteron breakup was observed for photon energies from 45 to 95 MeV. The angular distribution of the np pairs was measured for opening angles from 122 to 202 degrees in the laboratory frame. The single-differential cross section in Ω_p was determined at θ_p=81 degree, relative to deuterium, to range from 2.4 at 55 MeV to 1.7 at 95 MeV

[en] A search for the production of bound tetraneutrons has been carried out with a time projection chamber using the reaction ⁴He(π^-,π⁺)⁴n at T_π^-=80 MeV and at 50 degree <θ_lab^π+<130 degree. No evidence for tetraneutron formation was found, and a 90% confidence level upper limit for the production cross section of dσ/dΩ≤13 nb sr^-1 was obtained

[en] We have studies some processes related to tritium transport in solid blanket by some experiments. Diffusion processes have been studied by in-situ tritium release experiments under neutron irradiation at elevated temperatures. Diffusion coefficients of tritium in a grain and along grain boundaries of Li₂O and LiAlO₂ were determined separately. Surface reaction was also considered to be quite important for tritium release. Chemical form of released tritium as well as tritium release kinetics depended upon the composition of sweep gas. Basic studies on surface reactions have been also performed on Li₂O and LiAlO₂: (1) Water vapor sorption was investigated by a breakthrough method. Water vapor was considered to be adsorbed dissociatively on the surface of the grains or pores of sintered materials of Li₂O and LiAlO₂. The amount adsorbed on these materials decreased with increasing temperature. (2) Dissociative absorption was considered. Breakthrough method was considered to have a limitation in studying absorption process. (3) Exchange reaction between adsorbed tritiated water and hydrogen in gas phase was studied by a column method. Hydrogen tritide (HT) was found to be produced by an exchange reaction on the surface of the breeding materials. By combining these basic data obtained in these experiment and modeling effort, studies on tritium inventory and migration will be effectively performed. (author)

[en] We have measured the cross section for radiative capture of thermal neutrons on ³He. The measured cross section of 54±6 μb is used to estimate the astrophysical S factor for the reaction ³He(p,e⁺ν)⁴He which gives rise to high-energy neutrinos from the Sun

[en] All the ²H(γ,p)n data in the energy range 20--440 MeV have been fitted to a simple phenomenological function. All differential cross-section data were used: The bremsstrahlung data were normalized to the total cross-section values obtained by fitting data provided by monochromatic photon beams. The results obtained give a good representation of the experimental points

[en] Short note