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Presents a study that applied computer simulation to determine damage processes during ion implantation. Background on the Marlowe computer code; Development of a computational model for the code; Analysis of the results of impact-collision ion scattering spectroscopy.

Short-period (<1 s) seismograms are strongly affected by small-scale (<10 km) heterogeneities in the lithosphere. In general, short-period seismograms are analysed based on the statistical method by considering the interaction between seismic waves and randomly distributed small-scale heterogeneities. Statistical properties of the random heterogeneities have been estimated by analysing short-period seismograms. However, generally, the smallscale random heterogeneity is not taken into account for the modelling of long-period (>2 s) seismograms. We found that the energy of the coda of long-period seismograms shows a spatially flat distribution. This phenomenon is well known in short-period seismograms and results from the scattering by small-scale heterogeneities. We estimate the statistical parameters that characterize the small-scale random heterogeneity by modelling the spatiotemporal energy distribution of long-period seismograms. We analyse three moderate-size earthquakes that occurred in southwest Japan. We calculate the spatial distribution of the energy density recorded by a dense seismograph network in Japan at the period bands of 8-16 s, 4-8 s and 2-4 s and model them by using 3-D finite difference (FD) simulations. Compared to conventional methods based on statistical theories, we can calculate more realistic synthetics by using the FD simulation. It is not necessary to assume a uniform background velocity, body or surface waves and scattering properties considered in general scattering theories. By taking the ratio of the energy of the coda area to that of the entire area, we can separately estimate the scattering and the intrinsic absorption effects. Our result reveals the spectrum of the random inhomogeneity in a wide wavenumber range including the intensity around the corner wavenumber as P(m) = 8πε²a³/(1 + a²m²)², where ε = 0.05 and a = 3.1 km, even though past studies analysing higher-frequency records could not detect the corner. Finally, we estimate the intrinsic attenuation by modelling the decay rate of the energy. The method proposed in this study is suitable for quantifying the statistical properties of long-wavelength subsurface random inhomogeneity, which leads the way to characterizing a wider wavenumber range of spectra, including the corner wavenumber. [ABSTRACT FROM AUTHOR]

A collective Thomson scattering (CTS) diagnostic was developed and used to measure the bulk and fast ions originating from 180 keV neutral beams in the Large Helical Device (LHD). Electromagnetic waves from a gyrotron at 77 GHz with 1 MW power output function as both the probe and electron cyclotron heating beam. To clarify the diagnostic applicability of the gyrotron in the 77 GHz frequency band, we investigated the dependence of the probe and receiver beam trajectories in plasmas with high electron densities of (4–5) × 1019 m−3 and low electron densities of (1–2) × 1019 m−3. At high density, a stray radiation component was observed in the CTS spectrum whereas it was negligibly small at low density. The CTS spectrum was measured and analysed after the in situ beam alignment using a beam scan. Qualitatively, the CTS spectrogram shows consistent response to ion temperatures of 1–2 keV for electron densities of (1–2) × 1019 m−3 and electron temperatures of 2–4 keV. The measured CTS spectrum shows an asymmetric shape at the foot of the bulk-ion region during the injection of 180 keV fast ions. This shape is explained by the fast-ion distribution in the velocity space (v‖, v⊥) based on Monte Carlo simulation results. The analysis method of the CTS spectra is used to evaluate the ion temperature and fast-ion velocity distribution from the measured CTS data. [ABSTRACT FROM AUTHOR]

We present the results of experimental studies of submillimeter-wave gyrotrons, which were obtained in the Research Center for Development of Far-Infrared Region of Fukui University (Japan). Distinctive features of the systems forming helical electron beams in submillimeter-wave gyrotrons are described. The results of the theoretical studies, which were aimed at excitation of higher harmonics in submillimeter-wave gyrotrons, reducing the operating voltage, and creating devices with smooth wideband tuning of the generation frequency, are presented. It is shown that modern gyrotrons are capable of ensuring continuous-wave generation at the frequencies from 200 to 400 GHz at a power level of up to hundreds of watts, and up to tens of kilowatts in the pulse-generation regime. [ABSTRACT FROM AUTHOR]

Samples of SnO2 doped with different amount of Fe (10–20%) and Sb (5–25%) were prepared by sol–gel method. Room temperature ferromagnetism was found to increase as a result of co-doping with Sb, as compared to SnO2 doped only with Fe. 57Fe Mössbauer spectra of almost all samples exhibited two paramagnetic doublets and a small subspectrum referring to magnetic relaxation at room temperature. Only the samples Sn0.65Fe0.2Sb0.15O2 − δ and Sn0.85Fe0.1Sb0.05O2 − δ with 4 h long annealing time showed well developed sextets and larger magnetic coercivity compared to that of the other samples. The sextet observed was considered to be due to precipitates like Sn doped α-Fe2O3. The results suggest that the origin of the magnetic interactions is enhanced by the presence of magnetic defects, which can interact with the iron ions by free carrier electrons. For the sample with precipitates, the grain boundary defects may play an important role of enhanced ferromagnetism. [ABSTRACT FROM AUTHOR]

The international HypHI collaboration is proposing a hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study neutron/proton rich hypernuclei and eventually to measure hypernuclear magnetic moments. As Phase 0 of the HypHI project, we propose the feasibility study of heavy ion induced hypernuclear spectroscopy by observing a mesonic weak decay from , and with 6Li beams at 2 A GeV impinging on a 12C target. The physics motivations, experimental setup and the expected results will be discussed. [Copyright &y& Elsevier]

The response functions of 25.4 cm (length) × 25.4 cm (diameter) NE213 organic liquid scintillator have been measured for neutrons in the energy range from 20 to 800 MeV at the Heavy-Ion Medical Accelerator in Chiba (HIMAC) and at the Research Center for Nuclear Physics (RCNP) of Osaka University. At HIMAC, white (continuous) energy spectrum neutrons were produced by the 400 MeV per nucleon carbon ion bombardment on a thick graphite target, whose energy spectrum has already been measured by Kurosawa et al., [Nucl. Sci. Eng. 132, 30 (1999)] and the response functions of the time-of-flight-gated monoenergetic neutrons in a wide energy range from 20 to 800 MeV were simultaneously measured. At RCNP, the quasi-monoenergetic neutrons were produced via 7Li(p,n)7Be reaction by 250 MeV proton beam bombardment on a thin 7Li target, and the TOF-gated 245 MeV peak neutrons were measured. The absolute peak neutron yield was obtained by the measurement of 478 keV gamma rays from the 7Be nuclei produced in a Li target. The measured results show that the response functions for monoenergetic neutrons <250 MeV have a recoil proton plateau and an edge around the maximum light output, which increases with increasing incident neutron energy, on the other hand >250 MeV, the plateau and the edge become unclear because the proton range becomes longer than the detector size and the escaping protons increase. It can be found that the efficiency of the 24.5 cm (diameter) × 25.4 cm (length) NE213 for the 250 MeV neutrons is ∼10 times larger than the 12.7 cm (length) × 12.7 cm (diameter) NE213, which is widely used as a neutron spectrometer. [ABSTRACT FROM AUTHOR]

Collective Thomson scattering (CTS) system is expected to be a strong diagnostic tool for measuring thermal and fast ion distribution function at a local point inside plasmas. The electron cyclotron resonance heating system using a gyrotron at the frequency range of 77 GHz has been installed at the large helical device (LHD). The feasibility of CTS system using the 77 GHz gyrotron is assessed in terms of scattering spectrum and a background noise of the electron cyclotron emission, which affect the signal to noise ratio, with the realistic plasma parameters and incident port locations of LHD. Based on the calculated scattering spectra for bulk and tail fast ion diagnostics, the scattering radiation receiver system with gyrotron frequency feedback circuit is proposed to avoid the frequency chirping. [ABSTRACT FROM AUTHOR]

Abstract: The behavior of thermally-induced generation of extremely photo-luminescent CuBr crystallites in the previously reported CuCl/KBr system has been investigated by in situ optical absorption and photoluminescence (PL) spectroscopy. Upon suitable annealing of the system, CuCl can be fully changed into CuBr characterized by extremely-high-intensity PL. The PL spectrum is generally composed of three emission bands due to free-exciton, bound-exciton and defect-related emissions, with their intensity ratio depending on the annealing history. For a suitably-annealed system, in which the bound-exciton emission is maximized and the defect-related one is minimized at 77K, extremely-high-intensity free-exciton PL is observed at room temperature. The integrated intensity of the room temperature free-exciton PL is ∼103 times larger than that of CuCl, despite the general recognition that PL from CuBr is much weaker than that from CuCl. [Copyright &y& Elsevier]