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Hirade, Tetsuya
Yodenshi Kagaku; Kiso Kara Oyo Made, p.127 - 132, 2021/08
Positron annihilation Age-MOmentum Correlation (AMOC) measurement is the coincidence measurement method of positron injection time, positron annihilation time and positron annihilation-rays energy. The methods for measurement and analysis of AMOC will be introduced briefly. Some of the interesting researches also will be introduced.
Fukaya, Yuki
Yodenshi Kagaku, (13), p.3 - 10, 2019/09
no abstracts in English
Fukaya, Yuki
Yodenshi Kagaku, (11), p.41 - 44, 2018/09
no abstracts in English
Hirade, Tetsuya
Yodenshi Kagaku, (11), p.33 - 40, 2018/09
The positron injected in insulating materials thermalizes at the end part of its track and forms Positronium (Ps) with one of excess electrons within 1 ps. Therefore, Ps formation can be a tool to investigate very fast processes like excess electron solvation in liquids. Many phenomena appeared in radiation chemistry researches for room temperature ionic liquids (ILs) are interesting and important for the application. Positron annihilation lifetime (PAL) measurements in ILs were carried out and anomalously long lifetime values of the shortest lifetime component were found in ILs. PAL and positron annihilation age-momentum correlation (AMOC) measurements were performed to clarify the reason of these anomalously long lifetime values and Ps bubble oscillation was finally discovered. Recent progresses are introduced with showing some results.
Kai, Takeshi; Yokoya, Akinari*; Fujii, Kentaro*; Watanabe, Ritsuko*
Yodenshi Kagaku, (8), p.11 - 17, 2017/03
It is thought to that the biological effects such as cell death or mutation are induced by complex DNA damage which are formed by several damage sites within a few nm. We calculated dynamic behavior of secondary electrons produced by primary electron and positon of high energy in water whose composition ratio is similar to biological context. The secondary electrons induce the ionization or electronic excitation near the parent cations. The decelerated electrons about 10% are distributed to their parent cations by the attractive Coulombic force. From the results, we predicted the following formation mechanism for the complex DNA damage. The electrons ejected from DNA could induce the ionization or the electronic excitation within the DNA. The electrons attracted by the Coulombic force are pre-hydrated in water layer of the DNA. The pre-hydrated electrons could induce to the DNA damage by dissociative electron transfer. As the results, the complex DNA damage with 1 nm could be formed by the interaction of not only the primary electron or positon but also the secondary electrons.
Hirade, Tetsuya
Yodenshi Kagaku, (4), p.3 - 8, 2015/02
Positron annihilation Age-MOmentum Correlation (AMOC) measurement is the coincidence measurement method of positron injection time, positron annihilation time and positron annihilation -rays energy. The methods for measurement and analysis of AMOC will be introduced briefly. Some of the interesting researches also will be introduced.
Kawasuso, Atsuo
Yodenshi Kagaku, (4), p.9 - 22, 2015/02
In this article, I report, the spin polarization of positrons emitted from radioisotopes, the development of spin-polarized beams, the fundamental aspects of spin-polarized positron annihilation method, and, the investigation of current-induced spin polarization on metal surfaces through the spin-polarized positronium annihilation.