Zobrazeno 1 - 10
of 20
pro vyhledávání: '"Ken Wada"'
Publikováno v:
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 480:49-55
A sealed positron source that can sufficiently reduce the backscattered component was fabricated using an aqueous 22 NaCl solution and a graphite backing material. The spin polarization of the emitted positrons was evaluated as 39%, which was 1.7 tim
Publikováno v:
Journal of Physics B: Atomic, Molecular and Optical Physics. 54:205202
Positronium emission from wurtzite GaN(0001) and AlN(0001) surfaces was observed by positronium time-of-flight spectroscopy. The positronium energy spectra contained two positronium components distinguished by their energies. Through detailed analyse
Autor:
Ken Wada, Shimpei Iida, Izumi Mochizuki, Yasuyuki Nagashima, Hiroki Terabe, Takayuki Tachibana, Akira Yagishita, Toshio Hyodo
Publikováno v:
Defect and Diffusion Forum. 373:309-312
We have studied the emission of ortho-positronium from alkali-metal coated polycrystalline tungsten surfaces. The positronium time-of-flight spectra show that the yield of the 5 eV positronium component increases by alkali-metal coating. In addition,
Autor:
Atsuo Kawasuso, Ken Wada, Toshio Hyodo, Izumi Mochizuki, Tetsuo Shidara, Masaki Maekawa, Kiyotaka Asakura, Yuki Fukaya, Hiroko Ariga
Publikováno v:
Physical chemistry chemical physics. 18(10):7085-7092
The exact structure of the rutile-TiO2(110)-(1 × 2) surface, which had been under debate over the past 30 years, was investigated using the newly developed technique of total-reflection high-energy positron diffraction (TRHEPD), which is a positron
Autor:
Takayuki Tachibana, Shimpei Iida, Yasuyuki Nagashima, Izumi Mochizuki, Hiroki Terabe, Bernardo Barbiellini, Akira Yagishita, Takashi Yamashita, Toshio Hyodo, Ken Wada
Publikováno v:
Surface Science. 641:68-71
The study of positronium emission from metal surfaces bombarded by slow positrons provides information on the topmost layer of the metals such as electron and positron energy levels because positronium atoms are formed as the result of the interactio
Autor:
Izumi Mochizuki, Toshio Hyodo, Akira Yagishita, Ken Wada, Koji Michishio, Yasuyuki Nagashima, R H Suzuki
Publikováno v:
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 785:5-8
The characteristics of a positronium beam produced using the photodetachment of positronium negative ions have been investigated. The yields of positronium atoms were in reasonable agreement with the result of particle trajectory simulation including
Autor:
Akira Yagishita, Tsuneto Kanai, Yasuyuki Nagashima, Toshio Hyodo, Toshiyuki Azuma, Izumi Mochizuki, Koji Michishio, Susumu Kuma, Ken Wada
Publikováno v:
Nature Communications
Nature Communications, Vol 7, Iss 1, Pp 1-5 (2016)
Nature Communications, Vol 7, Iss 1, Pp 1-5 (2016)
When an electron binds to its anti-matter counterpart, the positron, it forms the exotic atom positronium (Ps). Ps can further bind to another electron to form the positronium negative ion, Ps− (e−e+e−). Since its constituents are solely point-
Publikováno v:
physica status solidi c. 6:2497-2502
Ortho-positronium (o -Ps), which self-annihilates into 3γ with a lifetime of 142ns, may be quenched through various interactions with atoms and molecules. The quenching process of o -Ps in gases, (i) pick-off quenching, (ii) attachment (chemical) qu
Autor:
Toshio Hyodo, Izumi Mochizuki, Yuki Fukaya, Masaki Maekawa, Atsuo Kawasuso, Tetsuo Shidara, Ken Wada
Publikováno v:
The European Physical Journal D. 68
The brightness of a linac-based intense positron beam was enhanced for total-reflection high-energy positron diffraction (TRHEPD) measurements. The beam initially guided by a magnetic field was released into a non-magnetic region and followed by a tr
Autor:
Yasuyuki Nagashima, Toshio Hyodo, Ken Wada, Shimpei Iida, Takayuki Tachibana, Takashi Yamashita, Izumi Mochizuki
Publikováno v:
Journal of Physics: Condensed Matter. 28:475002
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 the coating show a new positronium energy component with a specific energy loss in addition to the