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Yields of protons emitted in the D+D reaction in Pd, Au/Pd/PdO, Ti, and Au foils are measured by a dE–E counter telescope for bombarding energies between 2.5 and 10 keV. The experimental yields are compared with those predicted from a parametrization of the cross section and stopping power at higher energies. It is found that for Ti and Au target the enhancement of the D(d,p)T reaction is similar to that observed with a deuterium gas target (several tens of eV). The dependence of the yields on the bombarding energy corresponds well to the screening potential parameters U[sub s]=250±15 eV for Pd and 601±23 eV for Au/Pd/PdO. Possible models of the enhancement obtained are discussed. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Fusion reactions 6Li(d,a)4He and 2H(d,p)3H were measured in liquid Li. An ultrasonic target system was developed to form acoustic cavitation bubbles in liquid Li as an additional target. The material uncertainties of the target surface, which have been noted in solid target experiments, were completely rejected because contaminants could be removed in the liquid phase. The Li + d reaction was not affected by the cavitation process, and the derived screening potential was Us = 543 ± 38(sta.) +|3 3(sys.) eV. This value can be explained by ionic Debye screening if liquid Li is regarded as a low-temperature dense plasma. The d + d reaction was found to be enhanced several times by Li cavitation, whereas the yield of the Li + d reaction remained constant; the ultrasonic effect depends strongly on the target conditions. The enhancement is caused not by Coulomb screening but by the high deuteron temperature in the cavity. The temperature was deduced from the energy dependence of the nuclear reaction enhancement rate as kTd = 590 ± 54(sta.) (sys.) eV. A kinematic analysis also yielded consistent results. Although no meaningful bubble fusion events were observed, extremely large reaction enhancements were occasionally observed. [ABSTRACT FROM AUTHOR]

The total cross sections were measured for coherent double neutral-pion photoproduction on the deuteron at incident energies below 0.9 GeV for the first time. No clear resonance-like behavior is observed in the excitation function for W γ d = 2.38 – 2.61 GeV , where the d ⁎ ( 2380 ) dibaryon resonance observed at COSY is expected to appear. The measured excitation function is consistent with the existing theoretical calculation for this reaction. The upper limit of the total cross section is found to be 0.034 μb for the dibaryon resonance at W γ d = 2.37 GeV (90% confidence level) in the γ d → π 0 π 0 d reaction. [ABSTRACT FROM AUTHOR]

The deposition behavior of hydrogen isotopes in tungsten is essential in fusion material research. A tungsten (W) foil was pre-implanted by deuterium ions (D 3 + ) with an energy of 20 keV/D and flux of 3.0 × 10 14 D/(cm 2 s) at room temperature until saturation state was confirmed by the proton yield of D(d,p)T reaction. The changes of D-concentration in surface layer have been obtained by D–D reaction analysis with low flux (0.6 μA) and high energy (75 keV) D + beam at several storage time after the implantation terminated. Furthermore, the static D-retention in this sample was also measured by elastic recoil detection analysis one year later. The saturated value of n D / n W in surface layer of W foil is (42 ± 3) at.% at fluence of 1.5 × 10 18 D/cm 2 . After beam stopped, the D-concentration decreased, and a static D-retention of about 3 at.% was found one year later. These results showed that more than 92% of deuterium precipitated in tungsten metal at saturated state was unstable. [ABSTRACT FROM AUTHOR]

Abstract: Multiple scattering of incident deuterium ions () on energy spectrum of protons originating from low energy D(d,p)T reaction in Beryllium, Molybdenum, Samarium and Gold foil was studied by comparing the experimental and simulated spectrum. The proton energy spectra were obtained during the implantation of deuterium ions with an energy of 20keV/D in these targets and analyzed by Monte-Carlo based nuclear reaction spectrum simulation program NRIBA. It has been observed that the asymmetry of energy spectra increase with target atomic numbers. Only simulations with detailed consideration of multiple scattering could agree with experimental spectra for all targets. It indicates that the multiple scattering plays an significant role in proton energy spectra for low energy D(d,p)T reaction in heavy metals. The program NRIBA that describes this effect in detail could be used to obtain accurate low energy D–D reaction analysis. [Copyright &y& Elsevier]

Abstract: A micro-beam NRA system, by means of a resonant nuclear reaction 1H(15N, αγ)12C, has been developed for the purpose of the 3D mapping of the hydrogen distribution in solids. To obtain the tens μm size of the beam spot, the combination of the newly proposed tapered glass capillary and a conventional quadrupole magnetic lens is employed. An Y patterned film on a substrate is prepared as an application of the developed system. The 6MeV 15N beam focused by glass capillaries down to 50μm successfully shows the hydrogen distribution. The in-plane NRA profile implies that the beam emitted from the glass capillary outlet is parallel, although the original beam has a considerable divergence. The NRA measurements in the 103 Pa N2 atmosphere due to the low gas conductance of the glass capillary is also demonstrated. [Copyright &y& Elsevier]