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Tominaga, Masahide*; Nagayasu, Yukari*; Sasaki, Motoharu*; Furuta, Takuya; Hayashi, Hiroaki*; Oita, Masataka*; Nishiyama, Yuichi*; Haga, Akihiro*
Radiological Physics and Technology, 14(4), p.381 - 389, 2021/12
Due to recent advance of diagnostic radiology, the increase of diagnostic radiation exposure to patient becomes problem. Diagnostic Reference Levels has been released to optimized the radiation exposure to patients in Japan recently. The evaluation of entrance surface dose (ESD) is recommended to assess the dose level for general X-ray examination. The ESD can be easily evaluated by multiplying the backscatter factor of the patient body on the free-in-air air kerma. The air kerma free-in-air value used to estimate ESD may contain X-rays scattered from obstacles located at the time of measurement, which may induce non-minor error in assessments. We therefore studied the influence of scattered X-rays on air kerma measurement under various environments (distances, field sizes, and materials). It was found that the dependence on the X-ray energy and field size was different for different materials. The X-ray contamination can be ignored for all the materials when the distance to the scatterer exceeds 35 cm.
Tagawa, Akihiro; Ueda, Masashi; Yamashita, Takuya; Narisawa, Masataka*; Haga, Koichi*
Journal of Nuclear Science and Technology, 48(4), p.504 - 509, 2011/04
This paper describes the development of a new inspection robot for the in-service inspection of the heat transfer system of the fast breeder reactor MONJU. The inspection was carried out using a tire-type ultrasonic sensor for volumetric tests at high temperature (atmosphere, 55 C; piping surface, 80
C) and radiation exposure condition (dose rate, 10 mGy/h; piping surface dose rate, 15 mGy/h). An inspection robot using a new tire type for the ultrasonic testing sensor and a new control method was developed. A signal-to-noise ratio S/N over 2 was obtained during the functional test for a calibration defect with a depth of 50%t (from the tube wall thickness). In the automatic inspection test, an EDM slit with a depth of 9% from the pipe thickness was detectable and with an S/N ratio = 4.0 (12.0 dB).
Li, D. X.*; Kimura, Akihiro*; Haga, Yoshinori; Nimori, Shigeki*; Shikama, Tatsuo*
Journal of Physics; Condensed Matter, 23(7), p.076003_1 - 076003_7, 2011/02
Times Cited Count:13 Percentile:48.14(Physics, Condensed Matter)Higemoto, Wataru; Haga, Yoshinori; Matsuda, Tatsuma; Onuki, Yoshichika; Oishi, Kazuki; Ito, Takashi; Koda, Akihiro*; Saha, S. R.*; Kadono, Ryosuke*
Journal of the Physical Society of Japan, 75(12), p.124713_1 - 124713_5, 2006/12
Times Cited Count:12 Percentile:57.87(Physics, Multidisciplinary)Superconducting and magnetic properties of the heavy fermion superconductor CePtSi were studied by means of the
SR method. The muon Knight shift is invariant on passing the temperature through
down to 20 mK at 17 kOe, indicating that the local spin susceptibility does not change in the superconducting state.
Higemoto, Wataru; Haga, Yoshinori; Matsuda, Tatsuma; Onuki, Yoshichika; Koda, Akihiro*; Saha, S. R.*; Oishi, Kazuki; Kadono, Ryosuke*
Journal of the Physical Society of Japan, 75(Suppl.), p.180 - 182, 2006/08
We report on the Magnetism, magnetic penetration depth and the Knight shift in polycrystalline sample of CePtSi by means of muon spin rotation and relaxation method. The appearance of the internal field under the zero magnetic field in whole volume of the specimen, was observed, which indicating clear evidence of antiferromagnetism. The muon Knight shift was measured down to 20mK at 17kOe. Three different frequencies are seen in the muon spin rotation spectra, which depend on the temperature. The symmetry of the superconducting Cooper pair will be discussed.
Fujimori, Shinichi; Ino, Akihiro; Okane, Tetsuo; Fujimori, Atsushi; Harima, Hisatomo*; Aoki, Dai*; Ikeda, Shugo*; Shishido, Hiroaki*; Haga, Yoshinori; Tokiwa, Yoshifumi; et al.
Physica B; Condensed Matter, 312-313, p.132 - 133, 2002/03
Times Cited Count:1 Percentile:7.51(Physics, Condensed Matter)We have performed angle resolved photoemission experiments on heavy-fermion compounds CeRhIn and CeIrIn
. The obtained spectra are compared with the results of the full-potential linear-augmented-plane-wave (FLAPW) band-structure calculations, treating the Ce 4
electrons as being itinerant. The spectral contributions from the ligand Rh, Ir or In states were well reproduced by the calculations, although the features originated from Ce 4
states near
were not clearly observed.
Higemoto, Wataru; Sato, Kazuhiko*; Ito, Takashi; Nishida, Nobuhiko*; Oishi, Kazuki*; Heffner, R. H.; Haga, Yoshinori; Yamamoto, Etsuji; Kimura, Noriaki*; Onuki, Yoshichika; et al.
no journal, ,
The unconventional superconductivity in heavy fermion UPt attracted much interest. In recent neutron experiment, the narrowing of the AF Bragg peak at low temperature was observed, from which they suggest that a quasistatic AF long range order is realized below 20 mK. We have extended ZF-
SR measurement down to 8 mK to investigate the anomalous magnetic state over the very low temperature region. In our ZF-
SR, there is no significant change in the muon spinrelaxation rate down to 8 mK. The result suggests the absence of static or quasistaticmagnetic order over the relevant temperature range.
Ishimi, Akihiro; Haga, Hiroyuki; Katsuyama, Kozo; Maeda, Koji; Nagamine, Tsuyoshi
no journal, ,
no abstracts in English
Ishimi, Akihiro; Haga, Hiroyuki; Katsuyama, Kozo; Maeda, Koji; Nagamine, Tsuyoshi
no journal, ,
no abstracts in English