Development of in-reactor observation system using Cherenkov light, 5

Otsuka, Noriaki; Takeuchi, Tomoaki; Yamamoto, Keiichi; Shibata, Akira; Kimura, Nobuaki; Takemoto, Noriyuki; Tanimoto, Masataka; Tsuchiya, Kunihiko; Sano, Tadafumi*; Unesaki, Hironobu*; et al.

KURRI Progress Report 2013, P. 215, 2014/10

http://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2013/CO3.pdf#page=2

Investigation of a relation between reactor power and brightness of Cherenkov light at Kyoto University Research reactor (KUR) by a CCD camera was performed due to a development of a real-time in-core measurement technique using Cherenkov light. Analyzing the brightness value of individual RGB color component at each pixel, some of the G and B brightness values reached the maximum value of 8-bit binary number, i.e. 255, above about 2-3 MW. Therefore, we corrected the G and B brightness values by the R signals whose brightness value did not saturate even at 5 MW, the maximum reactor power of KUR. Then, the total brightness value was in proportion to the reactor power after the correction. These results indicate the reactor power can be estimated by the observation of Cherenkov light.

Effects of irradiation-particle energy on critical current density in Co-doped BaFeAs

Taen, Toshihiro*; Yagyuda, Hidenori*; Nakajima, Yasuyuki*; Tamegai, Tsuyoshi*; Okayasu, Satoru; Kitamura, Hisashi*; Murakami, Takeshi*; Laviano, F.*; Ghigo, G.*

Physica C, 484, p.62 - 65, 2013/01

https://doi.org/10.1016/j.physc.2012.02.040

We report effects of particle energy on physical properties of Co-doped BaFeAs in the case of Xe and Au irradiations. The irradiation-induced suppression of is found to be related with several factors, such as defect structures and the thickness of the crystal. Heavy-ion irradiation induces enhancement of critical current density , and a weak dip in the hysteresis loop. The fish-tail effect is completely suppressed by a modest density of defects. The enhancement of is closely related to the defect structure. Namely, splayed structure in columnar defects, inevitably introduced at lower energies, results in a strong enhancement of by forced entanglement of vortices.

Effects of particle irradiations on vortex states in iron-based superconductors

Tamegai, Tsuyoshi*; Taen, Toshihiro*; Yagyuda, Hidenori*; Tsuchiya, Yuji*; Mohan, S.*; Taniguchi, Tomotaka*; Nakajima, Yasuyuki*; Okayasu, Satoru; Sasase, Masato*; Kitamura, Hisashi*; et al.

Superconductor Science and Technology, 25(8), p.084008_1 - 084008_14, 2012/08

https://doi.org/10.1088/0953-2048/25/8/084008

Various kinds of energetic particles are irradiated into iron-based superconductors, and their effects on the critical current density and vortex dynamics have been systematically studied. It is found that is enhanced and vortex dynamics is strongly suppressed by energetic particles having a sufficient energy deposition rate, similar to the case of high temperature cuprate superconductors. The enhancement of , in general, persists up to much higher irradiation doses than in cuprates. However, details of the effect of irradiation depend on the kind of ion species and their energies. Even with the same ions and energies, the effect is not universal for different kinds of iron-based superconductors. The correlated nature of defects created by heavy-ion irradiation is confirmed by the angular dependence of irreversible magnetization.

Low-field anomaly of vortex dynamics in iron-pnictide superconductors

Tamegai, Tsuyoshi*; Taen, Toshihiro*; Yagyuda, Hidenori*; Nakajima, Yasuyuki*; Okayasu, Satoru; Sasase, Masato*; Kitamura, Hisashi*; Murakami, Takeshi*; Kambara, Tadashi*; Kanai, Yasuyuki*

Physica C, 471, p.777 - 780, 2011/00

https://doi.org/10.1016/j.physc.2011.05.052

Magnetic relaxations in Ba(FeCo)As before and after swift particle irradiations are measured. The normalized relaxation rate S shows a clear suppression in a pristine sample at low fields below the self-field. Heavy-ion irradiations suppress these anomalies considerably, although there still remain weak features depending on ion species and/or energies. In a proton irradiated sample, the low-field anomaly of S survives although it is smeared compared with that in a pristine sample. All these results indicate that the low-field anomaly of S is suppressed by defects, and correlated defects have stronger effects.

Critical current densities and flux creep rate in Co-doped BaFeAs with columnar defects introduced by heavy-Ion irradiation

Nakajima, Yasuyuki*; Tsuchiya, Yuji*; Taen, Toshihiro*; Yagyuda, Hidenori*; Tamegai, Tsuyoshi*; Okayasu, Satoru; Sasase, Masato*; Kitamura, Hisashi*; Murakami, Takeshi*

Physica C, 470(20), p.1103 - 1105, 2010/11

https://doi.org/10.1016/j.physc.2010.05.047

We report the formation of columnar defects in Co-doped BaFeAs single crystals with different heavy ion irradiations. The formation of columnar defects by 200 MeV Au ion irradiation is confirmed by transmission electron microscopy and their density is about 40% of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density is enhanced in the 200 MeV Au and 800 MeV Xe ion irradiated samples while is unchanged in the 200 MeV Ni ion irradiated sample. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFeAs and cuprate superconductors.

Feasible evaluation of neutron capture therapy for hepatocellular carcinoma using selective enhancement of boron accumulation in tumour with intra-arterial administration of boron-entrapped water-in-oil-in-water emulsion

Yanagie, Hironobu*; Kumada, Hiroaki*; Nakamura, Takemi; Higashi, Shushi*; Ikushima, Ichiro*; Morishita, Yasuyuki*; Shinohara, Atsuko*; Fujiwara, Mitsuteru*; Suzuki, Minoru*; Sakurai, Yoshinori*; et al.

Proceedings of 14th International Congress on Neutron Capture Therapy (ICNCT-14) (CD-ROM), p.157 - 160, 2010/10

Operation of the electrostatic accelerator

Takada, Isao; Mizuhashi, Kiyoshi; Uno, Sadanori; Okoshi, Kiyonori; Nakajima, Yoshinori; Chiba, Atsuya; Saito, Yuichi; Ishii, Yasuyuki; Sakai, Takuro; Kamiya, Tomihiro; et al.

JNC TN7200 2001-001, p.134 - 137, 2002/01

no abstracts in English

Status of the TIARA electrostatic accelerators

Tajima, Satoshi; Takada, Isao; Mizuhashi, Kiyoshi; Uno, Sadanori; Okoshi, Kiyonori; Nakajima, Yoshinori; Saito, Yuichi; Ishii, Yasuyuki; Kamiya, Tomihiro; Sakai, Takuro

Dai-11-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.37 - 40, 1999/01

no abstracts in English

Status of TIARA electrostatic accelerator facility

Tajima, Satoshi; ; Mizuhashi, Kiyoshi; Uno, Sadanori; Okoshi, Kiyonori; Nakajima, Yoshinori; Saito, Yuichi; Ishii, Yasuyuki; Sakai, Takuro; Kamiya, Tomihiro

F-113-'98/NIES, p.28 - 31, 1998/00

no abstracts in English

Status of the TIARA electrostatic accelerator facility

Tajima, Satoshi; ; Mizuhashi, Kiyoshi; Saito, Yuichi; Uno, Sadanori; ; Ishii, Yasuyuki; Nakajima, Yoshinori;

Dai-9-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, 0, p.10 - 13, 1996/00

no abstracts in English