We study the astrophysical reaction rate for the formation of 9 Be through the three body reaction α(αn, γ). This reaction is one of the key reactions which could bridge the mass gap at A = 8 nuclear systems to produce intermediate-to-heavy mass elements in alpha-and neutron-rich environments such as r-process nucleosynthesis in supernova explosions, s-process nucleosynthesis in asymptotic giant branch (AGB) stars, and primordial nucleosynthesis in baryon inhomogeneous cosmological models. To calculate the thermonuclear reaction rate in a wide range of temperatures, we numerically integrate the thermal average of cross sections assuming a two-steps formation through a metastable 8 Be, α + α ⇀ ↽ 8 Be(n,γ) 9 Be. Off-resonant and on-resonant contributions from the ground state in 8 Be are taken into account. As input cross section, we adopt the latest experimental data by photodisintegration of 9 Be with laser-electron photon beams, which covers all relevant resonances in 9 Be. Experimental data near the neutron threshold are added with γ-ray flux corrections and a new least-squares analysis is made to deduce resonance parameters in the Breit-Wigner formulation. Based on the photodisintegration cross section, we provide the reaction rate for α(αn, γ) 9 Be in the temperature range from T 9 =10 −3 to T 9 =10 1 (T 9 is the temperature in units of 10 9 K) both in the tabular form and in the analytical form for potential usage in nuclear reaction network calculations.The calculated reaction rate is compared with the reaction rates of the CF88 and the NACRE compilations. The CF88 rate, which is based on the photoneutron cross section for the 1/2 + state in 9 Be by Berman et al., is valid at T 9 > 0.028 due to lack of the off-resonant contribution. The CF88 rate differs from the present rate by a factor of two in a temperature range T 9 ≥ 0.1. The NACRE rate, which adopted different sources of experimental information on resonance states in 9 Be, is 4-12 times larger than the present rate at T 9 ≤ 0.028, but is consistent with the present rate to within ±20% at T 9 ≥ 0.1. 2

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Structural characterization of interfaces composed of soft materials (soft interfaces) helps in understanding their physical behavior. Neutron reflectometry is one of the most powerful tools to characterize interfacial structures with spatial resolution in nanometers. We have installed a novel horizontal-type time-of-flight neutron reflectometer SOFIA (SOFt Interface Analyzer) at the Japan Proton Accelerator Research Complex. The instrument is capable of accepting two downward neutron beams, at 2.21 and 5.71 to horizontal, which dedicate neutron reflectivity (NR) measurements over a wide range of neutron momentum transfer q (q ¼ (4p/k)sinh, where k and h are wavelength and incident angle, respectively). The accuracy of NR up to q ¼ 6 nm À1 was confirmed by measuring deuterated polystyrene (d-PS) thin films on a silicon (Si) wafer and multilayers of cadmium stearate prepared by the Langmuir-Blodgett method. NR at the deuterium oxide (D 2 O)/Si disk showed specular reflection down to 10 À6-10 À7 and q up to 2.0 nm À1 along the perpendicular to the sample surface, which improved the precise analysis of swollen polyelectrolyte brush structure at the D 2 O interface. Then, time-resolved in-situ NR measurements were carried out at 1-min intervals to observe interfacial mixing of d-PS on the PS brush surface during 398 K annealing, demonstrating that nonequilibrium behavior at the interfaces can be analyzed on the order of minutes.

New measurements of the photoneutron reaction on 181 Ta have been conducted with the AIST-LCS ͑laser Compton scattering͒ beam in the 7.8ՇE͓MeV͔Շ12 energy range. The major advantage of the present ␥-ray experiment is its intense peaking in the energy window of astrophysical interest, i.e., close to the neutron threshold. Details on photon beams from the laser Compton scattering, neutron counting, and experimental determination of the 181 Ta photoneutron cross section are given. The present experimental data are in good agreement with the IAEA evaluation. Reaction rate calculations in the Hauser-Feshbach statistical model are performed and confronted with the experimental data. The data provide constraints on the low-energy tail of the dipole strength function. It is found that among the three different models for the E1-strength considered, only the microscopic quasiparticle random phase approximation model can reproduce the extra strength observed in the 181 Ta(␥,n) 180 Ta reaction at energies of about 8.5 MeV. Such an experiment helps to improve the determination of the corresponding stellar photodisintegration rate of

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