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Journal Articles

Interlaboratory comparison of positron annihilation lifetime measurements

Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.

Materials Science Forum, 607, p.248 - 250, 2009/00

So far no standard procedure for the positron annihilation lifetime (PAL) technique has been established. A lack of the standards has led to difficulty in ensuring the equivalency and reliability of data from different laboratories. As a first, we conducted an interlaboratory comparison of PAL measurements for metal, polymer and silica glass with agreed procedures for data recording and analysis. The PAL data recorded at different laboratories were analyzed with a single lifetime component for the metal sample and with three components for the others, respectively. Based on the results of the reported positron and ortho-positronium lifetimes, the possible sources of the uncertainties in the PAL measurements are discussed. To reduce the effect of scattered $$gamma$$ rays, a lead shield was placed between the detectors. The uncertainty was significantly decreased, signifying that placing lead shields between the detectors effectively reduced the false signals due to the scattered $$gamma$$ rays.

Journal Articles

Interlaboratory comparison of positron annihilation lifetime measurements for synthetic fused silica and polycarbonate

Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.

Journal of Applied Physics, 104(2), p.026102_1 - 026102_3, 2008/07

 Times Cited Count:36 Percentile:18.88(Physics, Applied)

Interlaboratory comparison of positron annihilation lifetime measurements using synthetic fused silica and polycarbonate was conducted with the participation of 12 laboratories. By regulating procedures for the measurement and data analysis the uncertainties of the positron lifetimes obtained at different laboratories were significantly reduced in comparison with those reported in the past.

Journal Articles

Annealing of vacancy-type defect and diffusion of implanted boron in 6H-SiC

Oshima, Takeshi; Uedono, Akira*; Eryu, Osamu*; Lee, K. K.; Abe, Koji*; Ito, Hisayoshi; Nakashima, Kenshiro*

Materials Science Forum, 433-436, p.633 - 636, 2003/08

no abstracts in English

Journal Articles

Improvement of hydrogen absorption rate of Pd by ion irradiation

Abe, Hiroshi; Uchida, Hirohisa*; Azuma, Yorito*; Uedono, Akira*; Chen, Z. Q.*; Ito, Hisayoshi

Nuclear Instruments and Methods in Physics Research B, 206(1-4), p.224 - 227, 2003/05

 Times Cited Count:17 Percentile:23.61

Palladium(Pd) is used for the purification of H$$_{2}$$ gas and as a catalyst for the dissociation of H$$_{2}$$ molecules. Therefore, much work has been made until now. Since low energy ion irradiation, i.e., ion implantation is quite useful for surface modification of materials, the hydrogen absorption properties of Pd is expected to be improved by ion irradiation. In this work, we aimed at investigating the effect of ion irradiation on the hydrogen absorption rate of Pd. Ion irradiation was made with H$$^{+}$$, He$$^{+}$$ and Ar$$^{+}$$ in an acceleration energy rage from 30 to 350keV up to a dose of 1 x 10$$^{17}$$ /cm$$^{2}$$. As a result, ion irradiated Pd sample was found to induce a higher absorption rate than that of the unirradiated one. The initial hydrogen results suggest that defects introduced in Pd by ion irradiation facilitate tha rate of nucleation and growth of hydride.

Journal Articles

Positron annihilation study of vacancy-type defects in silicon carbide co-implanted with aluminum and carbon ions

Oshima, Takeshi; Uedono, Akira*; Abe, Hiroshi; Chen, Z. Q.*; Ito, Hisayoshi; Yoshikawa, Masahito; Abe, Koji*; Eryu, Osamu*; Nakashima, Kenshiro*

Physica B; Condensed Matter, 308-310, p.652 - 655, 2001/12

 Times Cited Count:6 Percentile:59.86

Co-implantation of Al(2E18/cm3) and C(1E18/cm3) into 6H-SiC and subsequent thermal annealing up to 1650 C werer carried out. Vacancy-type defects in the implanted layer were studied by monoenergetic positron beams. The mean size of vacancy-type defects in as-implanted samples is found to be close to the size of divacancy. Although vacancy clsters near a surface region were created by 1000 C-annealing, clustering is suppressed in a deep region.The mean size of vacancys decrease by annealing above 1000 C, and major vacancy defects annealed out after annealing at 1400 C. No significant difference in defect annealing between only Al- and co-implanted samles was observed.This result suggests that electrical activation of Al is enhanced by the site competition mechanism.

Journal Articles

Positron annihilation studies of defects in ion implanted palladium

Abe, Hiroshi; Uedono, Akira*; Uchida, Hirohisa*; Komatsu, A.*; Okada, Sohei; Ito, Hisayoshi

Materials Science Forum, 363-365, p.156 - 158, 2001/05

no abstracts in English

Journal Articles

Crystallization of an amorphous layer in P$$^{+}$$-implanted 6H-SiC studied by monoenergetic positron beams

Uedono, Akira*; Tanigawa, Shoichiro*; Oshima, Takeshi; Ito, Hisayoshi; Yoshikawa, Masahito; Nashiyama, Isamu; Frank, T.*; Pensl, G.*; Suzuki, Ryoichi*; Odaira, Toshiyuki*; et al.

Journal of Applied Physics, 87(9), p.4119 - 4125, 2000/05

 Times Cited Count:12 Percentile:48.06(Physics, Applied)

no abstracts in English

Journal Articles

Relationship between donor activation and defect annealing in 6H-SiC hot-implanted with phosphrous ions

Oshima, Takeshi; Uedono, Akira*; Ito, Hisayoshi; Yoshikawa, Masahito; Kojima, Kazutoshi; Okada, Sohei; Nashiyama, Isamu; Abe, Koji*; Tanigawa, Shoichiro*; Frank, T.*; et al.

Materials Science Forum, 338-342, p.857 - 860, 2000/00

no abstracts in English

Journal Articles

Study of residual defects in ion-implanted and subsequently annealed 3C-SiC

Oshima, Takeshi; Ito, Hisayoshi; Uedono, Akira*; Suzuki, Ryoichi*; Ishida, Yuki*; Takahashi, Tetsuo*; Yoshikawa, Masahito; Kojima, Kazutoshi; Odaira, Toshiyuki*; Nashiyama, Isamu; et al.

Denshi Gijutsu Sogo Kenkyujo Iho, 62(10-11), p.469 - 476, 1999/00

no abstracts in English

Journal Articles

Oxygen-related defects in O$$^{+}$$-implanted 6H-SiC studied by monoenergetic positron beams

Uedono, Akira*; Tanigawa, Shoichiro*; Oshima, Takeshi; Ito, Hisayoshi; Aoki, Yasushi; Yoshikawa, Masahito; Nashiyama, Isamu

Journal of Applied Physics, 86(10), p.5392 - 5398, 1999/00

 Times Cited Count:9 Percentile:54.52(Physics, Applied)

no abstracts in English

Journal Articles

Annealing behaviours of defects in electron-irradiated diamond probed by positron annihilation

Uedono, Akira*; *; Morishita, Norio; Ito, Hisayoshi; Tanigawa, Shoichiro*; *; *

Journal of Physics; Condensed Matter, 11(25), p.4925 - 4934, 1999/00

 Times Cited Count:10 Percentile:45.13(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Defects in synthesized and natural diamond probed by positron annihilation

Uedono, Akira*; *; Morishita, Norio; Ito, Hisayoshi; Tanigawa, Shoichiro*; *

Journal of Physics; Condensed Matter, 11(20), p.4109 - 4122, 1999/00

 Times Cited Count:7 Percentile:55.3(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Investigation of positron moderator materials for electron-linac-based slow positron beamlines

Suzuki, Ryoichi*; *; Uedono, Akira*; Y.K.Cho*; Yoshida, Sadafumi*; Ishida, Yuki*; Oshima, Takeshi; Ito, Hisayoshi; *; Mikado, Tomohisa*; et al.

Japanese Journal of Applied Physics, Part 1, 37(8), p.4636 - 4643, 1998/08

 Times Cited Count:21 Percentile:30.66(Physics, Applied)

no abstracts in English

Journal Articles

Investigation of vacancy-type defects in P$$^{+}$$-implanted 6H-SiC using monoenergetic positron beams

Uedono, Akira*; Oshima, Takeshi; Ito, Hisayoshi; Suzuki, Ryoichi*; *; Tanigawa, Shoichiro*; Aoki, Yasushi; Yoshikawa, Masahito; Nashiyama, Isamu; Mikado, Tomohisa*

Japanese Journal of Applied Physics, Part 1, 37(5A), p.2422 - 2429, 1998/05

 Times Cited Count:12 Percentile:46.08(Physics, Applied)

no abstracts in English

Journal Articles

Characterization of vacancy-type defects and phosphorus donors introduced in 6H-SiC by ion implantation

Oshima, Takeshi; Uedono, Akira*; Abe, Koji*; Ito, Hisayoshi; Aoki, Yasushi; Yoshikawa, Masahito; Tanigawa, Shoichiro*; Nashiyama, Isamu

Applied Physics A, 67(4), p.407 - 412, 1998/00

 Times Cited Count:25 Percentile:26.2(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Study of thermal annealing of vacancies in ion implanted 3C-SiC by positron annihilation

Oshima, Takeshi; Uedono, Akira*; Ito, Hisayoshi; Abe, Koji*; Suzuki, Ryoichi*; *; Aoki, Yasushi; Tanigawa, Shoichiro*; Yoshikawa, Masahito; Mikado, Tomohisa*; et al.

Mater. Sci. Forum, 264-268, p.745 - 748, 1998/00

no abstracts in English

Journal Articles

Characterization of residual defects in cubic silicon carbide subjected to hot-implantation and subsequent annealing

Ito, Hisayoshi; Oshima, Takeshi; Aoki, Yasushi; Abe, Koji*; Yoshikawa, Masahito; Nashiyama, Isamu; Okumura, Hajime*; Yoshida, Sadafumi*; Uedono, Akira*; Tanigawa, Shoichiro*

Journal of Applied Physics, 82(11), p.5339 - 5347, 1997/12

 Times Cited Count:13 Percentile:40.75(Physics, Applied)

no abstracts in English

Journal Articles

Annealing properties of defects in ion-implanted 3C-SiC studied using monoenergetic positron beams

Uedono, Akira*; Ito, Hisayoshi; Oshima, Takeshi; Suzuki, Ryoichi*; *; Tanigawa, Shoichiro*; Aoki, Yasushi; Yoshikawa, Masahito; Nashiyama, Isamu; Mikado, Tomohisa*; et al.

Japanese Journal of Applied Physics, Part 1, 36(11), p.6650 - 6660, 1997/11

 Times Cited Count:16 Percentile:34.88(Physics, Applied)

no abstracts in English

Journal Articles

Positron annihilation studies of defects in 3C-SiC hot-implanted with nitrogen and aluminum ions

Ito, Hisayoshi; Uedono, Akira*; Oshima, Takeshi; Aoki, Yasushi; Yoshikawa, Masahito; Nashiyama, Isamu; Tanigawa, Shoichiro*; Okumura, Hajime*; Yoshida, Sadafumi*

Applied Physics A, 65(3), p.315 - 323, 1997/00

 Times Cited Count:16 Percentile:34.88(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Defects in ion-implanted 3C-SiC probed by a monoenergetic positron beam

Uedono, Akira*; Ito, Hisayoshi; Oshima, Takeshi; Aoki, Yasushi; Yoshikawa, Masahito; Nashiyama, Isamu; Okumura, Hajime*; Yoshida, Sadafumi*; *; *; et al.

Japanese Journal of Applied Physics, Part 1, 35(12A), p.5986 - 5990, 1996/12

no abstracts in English

27 (Records 1-20 displayed on this page)