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Journal of Radioanalytical and Nuclear Chemistry
Authors:
A. Shinohara
,
T. Muroyama
,
T. Miura
,
A. Yokoyama
,
K. Takamiya
,
T. Kaneko
,
T. Saito
,
J. Sanada
,
H. Araki
,
S. Kojima
,
Y. Hamajima
,
H. Muramatsu
,
H. Baba
, and
M. Furukawa

Abstract  

Pionic X-rays and π0 decays were measured for gas mixtures of H2/D2/CH4+SF6/Ar and the individual pure gases. Chemical effects on the pion transfer process from pionic hydrogen to other atoms were revealed by the pionic X-ray spectrum. The changes of the intensity patterns of pionic X-rays were compared with the predictions by a cascade calculation taking the transfer process into account. The mechanism of pion transfer process was discussed based on the results for gas phase and the previous ones for liquid phase.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
K. Ninomiya
,
H. Sugiura
,
T. Nakatsuka
,
Y. Kasamatsu
,
H. Kikunaga
,
W. Sato
,
T. Yoshimura
,
H. Matsumura
,
K. Takamiya
,
M. Kubo
,
K. Sueki
,
A. Yokoyama
,
Y. Hamajima
,
T. Miura
,
K. Nishiyama
, and
A. Shinohara

Abstract  

The electronic X-ray energies of muonic atoms were precisely measured. The atomic number (Z) dependence of the energy difference between electronic X-rays of muonic atoms and Z-1 atoms (energy shift) was systematically investigated. The energy shifts in the low-Z region were compared with those of the high-Z region that had been obtained experimentally and theoretically in previous work. An obvious difference between these two regions was found in the atomic-number dependence of the energy shift. We also compared the energy shifts of muonic atoms with those of pionic atoms.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
T. Muroyama
,
A. Shinohara
,
T. Saito
,
A. Yokoyama
,
K. Takamiya
,
S. Morimoto
,
K. Nakanishi
,
H. Baba
,
T. Miura
,
Y. Hamajima
,
T. Kaneko
,
H. Muramatsu
,
S. Kojima
, and
M. Furukawa

Abstract  

Annihilation γ-rays of π0 and pionic X-rays were measured in the gas mixtures of H2+Z and CH4+Z systems (Z=He, Ne, Ar and Kr). Pion capture probability of hydrogen atom was obtained from the annihilation γ-ray counts and the capture probability of Z atom was obtained from the pionic X-ray intensities. Transfer rates were determined from the data based on a combined large mesomolecular model. The transfer rates obtained were smaller than the systematics of the Russian group. Difference in the transfer rate between the gas and the liquid phases was found by a comparison of the present results with our previous ones.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
R. Suzuki
,
T. Ohdaira
,
K. Yamada
,
T. Yamazaki
,
N. Sei
,
T. Mikado
,
T. Noguchi
,
H. Ohgaki
,
S. Sugiyama
,
M. Chiwaki
,
T. Shimizu
,
M. Kawai
,
M. Yokoyama
,
S. Hamada
,
K. Saeki
,
N. Nishimura
, and
T. Tomimasu

Abstract  

A positron lifetime study has been done on dielectric multilayer cavity mirrors for free-electron-laser experiments by the use of a variable-energy pulsed positron beam. A long-lived ortho-positronium component has been observed at low positron energy region, corresponding to the depth of the top amorphous SiO2 layer. The intensity of the positronium component correlates with the degradation and restoration of the mirrors. We discuss the relation between the positronium intensity and degradation mechanism of the mirrors. The present studies revealed that the slow positron lifetime technique is highly sensitive to the properties of the mirrors and is useful for the evaluation of the mirrors.

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