A5087174521- Muon and positron interactions and applications
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Graphene research and applications
- Particle accelerators and beam dynamics
- Diamond and Carbon-based Materials Research
- Ammonia Synthesis and Nitrogen Reduction
- Advanced Chemical Physics Studies
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- ZnO doping and properties
- Laser-induced spectroscopy and plasma
- Cold Atom Physics and Bose-Einstein Condensates
- High-pressure geophysics and materials
- Plasma Diagnostics and Applications
- Atmospheric Ozone and Climate
- Inorganic Fluorides and Related Compounds
- Electronic and Structural Properties of Oxides
- nanoparticles nucleation surface interactions
- Ga2O3 and related materials
- Pulsed Power Technology Applications
- Particle Accelerators and Free-Electron Lasers
- Infectious Diseases and Mycology
- Advanced NMR Techniques and Applications
- Thin-Film Transistor Technologies
Tokyo University of Science
2010-2023
Shimane University
2022
City Hospital
2022
Community Care
2022
Rikkyo University
2008-2019
Tohoku University
2014
High Energy Accelerator Research Organization
2012
Institute of Materials Structure Science
2012
Osaka Institute of Technology
2010
Gakushuin University
2003-2006
Photodetachment of the positronium negative ion, a bound state one positron and two electrons, has been observed. Development method to produce ions efficiently using Na coated tungsten surface enabled first observation photodetachment. The obtained lower limit photodetachment cross section for wavelength 1064 nm is consistent with theoretical calculations reported so far. experimental field developed in present work gives new opportunities explore quantum mechanical three-body problem...
We report here the production of an energy-tunable monoenergetic positronium beam using photodetachment negative ion, a bound state one positron and two electrons. The ions were produced efficiently by bombarding Na-coated tungsten surface with pulsed slow accelerated static electric field. On irradiating high intensity laser light, hitherto unrealized energy range up to 1.9 keV has been in ultra vacuum environment.
The emission of positronium negative ions from Na- and K-coated W(100) surfaces has been studied. efficiencies (the fractions incident slow positrons yielding the ions) for both samples were found to be as high 1.5%. Although decreased with time after coating, effects more durable than that Cs coating. In particular, efficiency Na coating was still higher 0.5% three days. successful development a Ps− source opens door new era experimental investigations on ion.
Recent development of the Slow Positron Facility at Institute Materials Structure Science, High Energy Accelerator Research Organization (KEK) is reported. The facility, equipped with a dedicated 55 MeV linac, provides high-intensity, pulsed slow-positron beam. beam produced in production unit high tension up to 35 kV and guided magnetically through grounded line, then branched using compact branching units experiment hall. An overview, some details three experiments currently conducted...
We have investigated the positron-stimulated desorption of ions from a ${\text{TiO}}_{2}(110)$ surface. Desorbed O${}^{+}$ were detected in coincidence with emission annihilation $\ensuremath{\gamma}$ rays. The energy dependence ion yields shows that at energies much lower than previously reported threshold for electron impact corresponding to excitation Ti($3p$) core electrons. These results provide evidence core-hole creation by positron electrons levels leads desorption.
We compared positron- and electron-stimulated desorption (e+SD ESD) of positive ions from a TiO2(110) surface. Although O+ was observed in both experiments, the efficiency caused by positron bombardment larger one order magnitude than that electron at an incident energy 500 eV. e+SD remained highly efficient with energies between 10 eV 600 The results indicate is predominantly pair annihilation surface-trapped positrons inner-shell electrons. also tested water chemisorbed on TiO2 surface...
Klebsiella ozaenae, a subtype of K. pneumonia, causes chronic upper respiratory tract infections, such as rhinitis and rhinoscleroma, can also cause lethal infections. We report the case patient who developed pneumonia caused by ozaenae. An 87-year-old man presented to our hospital with fever chills. Physical examination revealed no findings other than bilateral crackles in lower lung fields. Chest computed tomography (CT) showed infiltrative shadows left field. Moreover, ozaenae was...
Recently, we have observed the efficient emission of positronium negative ions from Cs coated W(100) and polycrystalline Mo Ta surfaces. The enables us to perform new experimental studies on these ions. investigations production are reviewed a measurement binding energy photodetachment experiment proposed.
The interaction of low-energy multiply charged Arq + (q ≤ 7) ions with a solid Ne surface is experimentally studied. Desorption very large cluster Nen (n > 100) observed. size distribution smaller = 1–3) depends strongly on the charge state incident ion, whereas that larger exhibits no dependence state, indicating desorption due to kinetic sputtering. potential sputtering yield estimated by analyzing desorbed ions. results suggest ion mechanism, which known as induced electronic transitions,...
Recent developments in the efficient production of positronium negative ions open door to a new era experimental investigations these ions. In present paper, studies so far are reviewed.
Experimental and computational studies of the positron-stimulated O ion desorption process from a TiO2(1 1 0) surface are reported. The measured data indicate that yields depend on positron incident energy in range between 0.5 keV 15 keV. This dependence is closely related to fraction positrons which diffuse back after thermalization bulk. Based experimental results, we conclude via positron-stimulation occurs dominantly by annihilation surface-trapped with core electrons topmost atoms.
We have studied the desorption of positive ions from a LiF(110) crystal surface using positron and electron irradiation at 500 eV to examine interaction between positrons ionic crystals. Only monatomic ions, such as ${\mathrm{H}}^{+}$, ${\mathrm{Li}}^{+}$, ${\mathrm{F}}^{+}$, are detected under irradiation. However, leads significant molecules, specifically, ${\mathrm{FH}}^{+}$ ${\mathrm{F}}_{2}^{+}$. Molecular ion yields more sensitive temperature than atomic yields. Based on findings, we...
Absolute sputtering yields from the surface of solid Ne by low energy He+ and Arq+ (1 ≥ q 6) impact are measured. Very large (300 atoms/ion for 1 keV impact, 3000 1keV Ar+ impact) have been observed. A significant dependence on chage state, i.e. potential energy, incident ion has not observed because it is estimated to be much smaller than that kinetic sputtering, which suggests mechanism similar those known electron- photon-stimulated desorption processes.
The emission of positronium negative ions from a Na coated W(100) surface has been studied. efficiency was found to increase with time following deposition maximum 1.4% after 6 × 104 s. then gradually decreased but still higher than 0.5% 3 days.
We investigated Ne + ions and n (n = 2 -20) cluster desorbed from the surface of solid by 1.0 keV Ar ion impact.Kinetic energy analysis shows a considerably narrower distribution for ≥ 3) than 1, 2) ions.The dependence yields on film thickness indicates that are only relatively thick films.We conclude grow into large during outflow deep bulk atoms to vacuum.
The production of an energy-tunable positronium beam by photodetachment negative ions, which was proposed many years ago, has become feasible the recent development efficient formation ions and successful photodetachment. Here we shall describe our current efforts directed towards a using this technique.
We have compared positron-annihilation-induced ion desorption from clean and contaminated TiO2 surfaces. While O+ ions the surface were detected, H+ was observed for surface. These results indicate that positron-stimulated is sensitive to changes in environment. [DOI: 10.1380/ejssnt.2015.261]
We have measured the time-of-flight of ortho-positronium emitted from Cs-, Na- and Li-coated single-crystal tungsten surfaces. The data obtained after coating show a new positronium energy component with specific loss in addition to whose emission is simply determined by positron electron work functions. suggest that this attributed formation accompanied inter-band transition and/or surface plasmon excitation at
Electron or photon irradiation of H2O adsorbed on the surface rare gas solids induces desorption protonated water clusters, (H2O)nH+. The yield and size n distribution cluster ions depend coverage, deposition temperature water, thickness film. These results indicate that (H2O)nH+ originate from isolated most important factor determining desorbed is sizes islands solid. measurement kinetic energy distributions indicated desorbing clusters species substrates size. It suggested due to Coulomb...