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Journal Articles

Analytical methods using a positron microprobe

Oka, Toshitaka; Jinno, Satoshi*; Fujinami, Masanori*

Analytical Sciences, 25(7), p.837 - 844, 2009/07

 Times Cited Count:13 Percentile:16.31(Chemistry, Analytical)

Positrons have been used for material analysis not only because of their novel characteristics, such as an ability to detect open-volume type defects in materials, but also because interactions with solids differ from those of electrons in such processes as scattering and diffraction. Monoenergetic positron beams and microbeams were developed in the 1980s, and positron experiments have made progress in material analyses. In this article we review the fundamental technique of microbeam fabrication, especially using a magnetically-guided positron beam, its extension to various analytical methods, and expectations for future research.

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:48 Percentile:83.42(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

Chemical state analysis of vacancy-impurity complexes by positron annihilation spectroscopy

Fujinami, Masanori*; Oguma, Koichi*; Akahane, Takashi*; Kawasuso, Atsuo; Maekawa, Masaki

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 151, 2007/02

no abstracts in English

Journal Articles

Positron annihilation spectroscopy to getter sites for Cu in Si

Fujinami, Masanori*; Miyagoe, Tatsuzo*; Akahane, Takashi*; Kawasuso, Atsuo; Maekawa, Masaki; Chen, Z. Q.*

JAEA-Review 2005-001, TIARA Annual Report 2004, p.235 - 237, 2006/01

no abstracts in English

Oral presentation

Comparison of positron annihilation measurements of quartz glass and polycarbonate

Kobayashi, Yoshinori*; Ito, Kenji*; Oka, Toshitaka*; Sakaki, Koji*; Shirai, Yasuharu*; Honda, Yoshihide*; Shimazu, Akira*; Fujinami, Masanori*; Hirade, Tetsuya; Saito, Haruo*; et al.

no journal, , 

For making a standard sample of positron annihilation measurement, quartz glass and polycarbonate were measured with 12 apparatus at AIST, Chiba Univ., Tokyo Univ., Tsukuba Univ., Touhoku Univ., Tokyo Gakugei Univ. JAEA, Nitto Denko, and Toray Research Center. By regulating procedure for the measurement and data analysis the uncertainties of the positron annihilation lifetime obtained at different laboratories were significantly reduced.

Oral presentation

Beam-line improvement and recent results of KEK-IMSS slow-positron facility

Wada, Ken*; Mochizuki, Izumi*; Hyodo, Toshio*; Kosuge, Takashi*; Saito, Yuki*; Shidara, Tetsuo*; Osawa, Satoshi*; Ikeda, Mitsuo*; Shirakawa, Akihiro*; Furukawa, Kazuro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Estimation of measurement uncertainty for positron annihilation lifetimes at an interlaboratory comparison

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

no journal, , 

An interlaboratory comparison for positron annihilation lifetime measurements for pure nickel, polycarbonate (PC) and fused silica was performed. Based on the reported data of positron (for nickel) and positronium (for PC and fused silica) components, the uncertainties in the PAL measurements were estimated and their possible source was discussed.

Oral presentation

Temperature dependence of free volume in polyethylene

Oka, Toshitaka; Jinno, Satoshi*; Fujiwara, Aya*; Fujinami, Masanori*

no journal, , 

Temperature dependence of free volume in polyethylene was investigated by positron annihilation lifetime spectroscopy. The relationship between the thermal expansion of free volume and the sample density was clearly shown.

Oral presentation

Development of positron probe microanalyzer using RI source and its applications

Fujinami, Masanori*; Jinno, Satoshi*; Oka, Toshitaka; Kawashima, Yuji*

no journal, , 

Oral presentation

Beam-line improvement and new experiment stations of KEK-IMSS slow-positron facility

Wada, Ken*; Mochizuki, Izumi*; Hyodo, Toshio*; Kosuge, Takashi*; Saito, Yuki*; Shidara, Tetsuo*; Osawa, Satoshi*; Ikeda, Mitsuo*; Shirakawa, Akihiro*; Furukawa, Kazuro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Interlaboratry comparison of psotitron annihilation lifetime measurement

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

no journal, , 

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 equivalency and reliability of data from different laboratories. Recently, as a first step toward the standardization of the PAL technique, we conducted an interlaboratory comparison of PAL measurements for fused silica, polycarbonate and metal with agreed procedures for data recording and analysis. Based on the results of the reported lifetimes, possible sources of the uncertainties in the PAL measurements is probably caused by the backscattered $$gamma$$-rays by other detectors. We succeeded to show that inserting shields between detectors can reduce the uncertainty.

Oral presentation

Present status of the KEK-IMSS Slow Positron Facility; A New beam-line branch and a rearrangement of the experiment stations

Wada, Ken*; Mochizuki, Izumi*; Hyodo, Toshio*; Kosuge, Takashi*; Saito, Yuki*; Nigorikawa, Kazuyuki*; Shidara, Tetsuo*; Osawa, Satoshi*; Ikeda, Mitsuo*; Shirakawa, Akihiro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Recent developments and results of the KEK slow positron facility

Wada, Ken*; Mochizuki, Izumi*; Hyodo, Toshio*; Kosuge, Takashi*; Saito, Yuki*; Nigorikawa, Kazuyuki*; Shidara, Tetsuo*; Osawa, Satoshi*; Ikeda, Mitsuo*; Shirakawa, Akihiro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Positron diffraction project at KEK slow positron facility

Hyodo, Toshio*; Fukaya, Yuki; Takahashi, Toshio*; Fujinami, Masanori*; Wada, Ken*; Mochizuki, Izumi*; Shidara, Tetsuo*; Kawasuso, Atsuo; Maekawa, Masaki; Shirasawa, Tetsuro*

no journal, , 

no abstracts in English

Oral presentation

In situ observation of defects in pure iron using gamma-ray-induced positron annihilation spectroscopy

Yabuuchi, Atsushi*; Hirade, Tetsuya; Fujinami, Masanori*; Awaji, Ryo*; Oshima, Nagayasu*; Takai, Kenichi*; Taira, Yoshitaka*; Sugita, Kento*

no journal, , 

In situ measurements of positron annihilation lifetimes have been performed at the UVSOR synchrotron radiation facility to characterise defects formed during tensile deformation of pure iron using the gamma-ray induced positron annihilation spectroscopy (GiPAS) technique. A dumbbell-shaped specimen was attached to a small tensile tester and stretched to a nominal strain of 7 or more at a strain rate of 2.2$$times$$10$$^{5}$$/s. Positron lifetime changes during tensile deformation of a pure iron specimen were observed using positrons generated in the sample by irradiating the centre of the sample with a 66MeV gamma-ray pulse beam of 3mm in diameter. Unlike the results reported so far, the change in the positron lifetime, especially at the early deformation stage, was very small, making clear the importance of in-situ measurement.

Oral presentation

Materials science at the KEK slow positron facility

Wada, Ken*; Mochizuki, Izumi*; Hyodo, Toshio*; Kosuge, Takashi*; Saito, Yuki*; Nigorikawa, Kazuyuki*; Shidara, Tetsuo*; Osawa, Satoshi*; Ikeda, Mitsuo*; Shirakawa, Akihiro*; et al.

no journal, , 

no abstracts in English

Oral presentation

In-situ positron lifetime measurements of pure iron during tensile deformation using gamma-ray-induced positron annihilation spectroscopy

Yabuuchi, Atsushi*; Awaji, Ryo*; Hirade, Tetsuya; Fujinami, Masanori*; Oshima, Nagayasu*; Takai, Kenichi*; Taira, Yoshitaka*

no journal, , 

In situ measurements of positron annihilation lifetimes have been performed at the UVSOR synchrotron radiation facility to evaluate defects formed during tensile deformation in pure iron using the gamma-ray induced positron annihilation spectroscopy technique. A 66 MeV gamma-ray pulse beam with a diameter of 3 mm was irradiated to the centre of the sample while stretching it to a nominal strain of 7 or more at a strain rate of 2.2$$times$$10$$^{5}$$/s. The positron lifetime change during the tensile deformation of iron specimens was observed. Positron lifetime measurements have often been performed after the deformation of the sample. Unlike these results, it was found that the lifetime change at the initial deformation stage was very small in these In situ measurements.

Oral presentation

Positron annihilation in vacancy-Cu complexes in Si

Fujinami, Masanori*; Watanabe, Kazuya*; Oguma, Koichi*; Akahane, Takashi*; Kawasuso, Atsuo; Maekawa, Masaki; Matsukawa, Kazuto*; Harada, Hirofumi*

no journal, , 

no abstracts in English

Oral presentation

Positron annihilation study of impurity gettering in Si

Akahane, Takashi*; Fujinami, Masanori*; Watanabe, Kazuya*; Oguma, Koichi*; Matsukawa, Kazuto*; Harada, Hirofumi*; Maekawa, Masaki; Kawasuso, Atsuo

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)