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Journal Articles

General overview of the research project investigating the radionuclide solution behavior in mock mortar matrix modeled after conditions at the Fukushima-Daiichi Nuclear Power Station

Igarashi, Go*; Haga, Kazuko*; Yamada, Kazuo*; Aihara, Haruka; Shibata, Atsuhiro; Koma, Yoshikazu; Maruyama, Ippei*

Journal of Advanced Concrete Technology, 19(9), p.950 - 976, 2021/09

Journal Articles

A Project focusing on the contamination mechanism of concrete after the accident at Fukushima Daiichi Nuclear Power Plant

Yamada, Kazuo*; Maruyama, Ippei*; Haga, Kazuko*; Igarashi, Go*; Aihara, Haruka; Tomita, Sayuri*; Kiran, R.*; Osawa, Norihisa*; Shibata, Atsuhiro; Shibuya, Kazutoshi*; et al.

Proceedings of International Waste Management Symposia 2021 (WM 2021) (CD-ROM), 10 Pages, 2021/03

Journal Articles

New project on the analysis of contamination mechanisms of concrete at the Fukushima Daiichi Nuclear Power Station

Yamada, Kazuo*; Maruyama, Ippei*; Koma, Yoshikazu; Haga, Kazuko*; Igarashi, Go*; Shibuya, Kazutoshi*; Aihara, Haruka

Proceedings of International Waste Management Symposia 2019 (WM 2019) (CD-ROM), 6 Pages, 2019/03

Journal Articles

Beam monitor deformation by Tohoku Earthquake and its recovery project

Miura, Akihiko; Hasegawa, Kazuo; Oguri, Hidetomo; Ouchi, Nobuo; Igarashi, Zenei*; Miyao, Tomoaki*; Ikegami, Masanori*

Proceedings of 2nd International Particle Accelerator Conference (IPAC 2011) (Internet), p.2328 - 2330, 2011/09

On March 11, 2011, the great earthquake occurred off the Pacific coast of Tohoku. This earthquake and related ones caused the big damage of the J-PARC accelerators. As for the beam monitors in J-PARC linac, some commissioning tools had damage and the vacuum leakage was observed. In the recovery work, we inspected the damage and put the emergency steps for the vacuum equipment. In this paper, detailed inspection results of beam monitors are described and also the recovery work is introduced.

Journal Articles

Beam loss detected by scintillation monitor

Miura, Akihiko; Maruta, Tomofumi; Sako, Hiroyuki; Hasegawa, Kazuo; Ouchi, Nobuo; Igarashi, Zenei*; Miyao, Tomoaki*; Ikegami, Masanori*

Proceedings of 2nd International Particle Accelerator Conference (IPAC 2011) (Internet), p.1257 - 1259, 2011/09

Ar-CO$$_{2}$$ gas proportional beam loss monitors (BLMs) have measured the beam loss through operations, but they are also sensitive to background noise of X-ray emitted from RF cavities. For the future energy upgrade of J-PARC linac, because 21 RF cavities are additionally installed in the beam line, the background noise would be serious problem. We employed the scintillation monitors to measure the beam loss which would bring more accurate beam loss measurements with suppression of X-ray noise. As the measurement results, a good signal to noise ratio is observed for the scintillation monitor with quite low sensitivity to the background X-ray. In addition, the availability of the scintillation monitor is also confirmed at the low energy part. This paper describes the beam loss measurement system using a scintillation monitor.

Journal Articles

Beam loss detected by scintillation monitor

Miura, Akihiko; Maruta, Tomofumi; Sako, Hiroyuki; Hasegawa, Kazuo; Ouchi, Nobuo; Igarashi, Zenei*; Miyao, Tomoaki*; Ikegami, Masanori*

Proceedings of 10th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators (DIPAC 2011) (Internet), p.149 - 151, 2011/08

Ar-CO$$_{2}$$ gas proportional beam loss monitors (BLMs) have measured the beam loss through operations, but they are also sensitive to background noise of X-ray emitted from RF cavities. For the future energy upgrade of J-PARC linac, because 21 RF cavities are additionally installed in the beam line, the background noise would be serious problem. We employed the scintillation monitors to measure the beam loss which would bring more accurate beam loss measurements with suppression of X-ray noise. As the measurement results, a good signal to noise ratio is observed for the scintillation monitor with quite low sensitivity to the background X-ray. This paper describes the beam loss measurement system using a scintillation monitor.

Journal Articles

Beam loss detection by scintillation monitor

Miura, Akihiko; Maruta, Tomofumi; Sako, Hiroyuki; Hasegawa, Kazuo; Ouchi, Nobuo; Igarashi, Zenei*; Miyao, Tomoaki*; Ikegami, Masanori*

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08

Ar-CO$$_{2}$$ gas proportional beam loss monitors (BLMs) have measured the beam loss through operations, but they are also sensitive to background noise of X-ray emitted from RF cavities. For the future energy upgrade of J-PARC linac, because 21 RF cavities are additionally installed in the beam line, the background noise would be serious problem. We employed the scintillation monitors to measure the beam loss which would bring more accurate beam loss measurements with suppression of X-ray noise. As the measurement results, a good signal to noise ratio is observed for the scintillation monitor with quite low sensitivity to the background X-ray. This paper describes the beam loss measurement system using a scintillation monitor.

Journal Articles

Tuning of MEBT-Chopper by using wire scanner monitor

Sato, Susumu; Miura, Akihiko; Igarashi, Zenei*; Ikegami, Masanori*; Ueno, Akira; Sako, Hiroyuki; Morishita, Takatoshi; Yoshikawa, Hiroshi; Hasegawa, Kazuo; Kobayashi, Tetsuya

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.298 - 300, 2010/03

no abstracts in English

Journal Articles

Design of beam diagnostic systems for energy upgraded linac

Miura, Akihiko; Sato, Susumu; Sako, Hiroyuki; Yoshikawa, Hiroshi; Hasegawa, Kazuo; Igarashi, Zenei*; Ikegami, Masanori*

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.733 - 735, 2010/03

no abstracts in English

Journal Articles

Study of J-PARC linac beam position monitor as phase monitor

Sato, Susumu; Miura, Akihiko; Tomisawa, Tetsuo; Sako, Hiroyuki; Morishita, Takatoshi; Ueno, Akira; Hasegawa, Kazuo; Yoshikawa, Hiroshi; Igarashi, Zenei*; Ikegami, Masanori*

Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.3591 - 3593, 2009/05

Journal Articles

Commissioning strategies for J-PARC linac and L3BT

Ikegami, Masanori*; Lee, S.*; Akikawa, Hisashi*; Igarashi, Zenei*; Kondo, Yasuhiro; Okawa, Tomohiro; Ueno, Akira; Sako, Hiroyuki; Ao, Hiroyuki; Sato, Susumu; et al.

KEK Proceedings 2006-15 (CD-ROM), p.347 - 349, 2007/03

We plan to start the beam commissioning of J-PARC linac with reduced energy of 181 MeV in the end of this year. Detailed commissioning strategies for the linac and the succeeding beam transport line, to which we refer as L3BT or Linac-to-3-GeV-synchrotron Beam Transport, will be presented in this talk. The emphasis will be put on the commissioning procedures for two debuncher cavities and a transverse collimator system located in L3BT, because they are key elements in determining the final beam quality at the injection point to the succeeding 3-GeV synchrotron. The unique design and features of the collimator system are also presented.

Journal Articles

Investigation of photo neutralization efficiency of high intensity H$$^{-}$$ beam with Nd:YAG laser in J-PARC

Tomisawa, Tetsuo; Akikawa, Hisashi; Sato, Susumu; Ueno, Akira; Kondo, Yasuhiro; Oigawa, Hiroyuki; Sasa, Toshinobu; Hasegawa, Kazuo; Lee, S.*; Igarashi, Zenei*; et al.

Proceedings of 7th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators (DIPAC 2005), p.275 - 277, 2005/00

The photo neutralization method with Nd:YAG laser for negative hydrogen ions has been expected as an available candidate for the transverse beam profile measurement. The fraction of photo detached electron can also be used for charge exchange procedure to extract very low power proton beam for Transmutation Experimental Facility in J-PARC. The laser system has advantages of maintenance and radiation hardness in high intensity proton accelerators. In order to establish the low power beam extraction system and beam profile monitor, the photo neutralization efficiency must be surveyed in practical beam line with high intensity H$$^{-}$$ beam. In this paper, an experimental set-up and preliminary results of photo neutralization method for intense H$$^{-}$$ beam in J-PARC MEBT1 are described.

Journal Articles

Beam commissioning of the J-PARC linac DTL1 at KEK

Kondo, Yasuhiro; Akikawa, Hisashi; Anami, Shozo*; Asano, Hiroyuki*; Fukui, Yuji*; Igarashi, Zenei*; Ikegami, Kiyoshi*; Ikegami, Masanori*; Ito, Takashi; Kawamura, Masato*; et al.

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.156 - 158, 2004/08

A commissioning of the J-PARC linac DTL1 is now under way at KEK. A 30mA H$$^{-}$$ beam was accelerated to 19.7-MeV, and 100% transmission was obtained with a 20-msec-pulse-width and 12.5-Hz-repetition beam. In this paper, present status of the DTL1 commissioning and preliminary results of the commissioning, such as emittance measurements, are presented.

Journal Articles

Systematic calibration of beam position monitor at J-PARC LINAC

Sato, Susumu; Tomisawa, Tetsuo; Hiroki, Fumio; Lee, S.*; Igarashi, Zenei*; Ikegami, Masanori*; Ueno, Akira; Kondo, Yasuhiro; Hasegawa, Kazuo; Toyama, Takeshi*; et al.

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.467 - 469, 2004/08

As a joint project of KEK and JAERI, a MW class of high intensity proton accelerator (J-PARC), consisting of Linac, 3 GeV-RCS, 50 GeV-MR, is under construction. For this accelerator, it is required to minimize the beam loss (typically, lower than0.1$$sim$$1 W/m at the linac). To achieve the requirement, beam trajectory needs to be controlled with accuracy of some 100 $$mu$$m. The first stage of the acceleration (up to 181 MeV during the first stage of construction) is done by linac. The beam position monitor (BPM) in the linac utilizes 4 stripline pickups (50 ohm) on the beam transportation chamber. In this paper, systematic calibration of the BPM is described.

Journal Articles

Systematic calibration of beam position monitor in the high intensity proton accelerator (J-PARC) linac

Sato, Susumu; Igarashi, Zenei*; Lee, S.*; Tomisawa, Tetsuo; Hiroki, Fumio; Kishiro, Junichi; Ikegami, Masanori*; Kondo, Yasuhiro; Hasegawa, Kazuo; Ueno, Akira; et al.

Proceedings of 22nd International Linear Accelerator Conference (LINAC 2004), p.429 - 431, 2004/00

As a joint project of KEK and JAERI, a MW class of high intensity proton accelerator (J-PARC), consisting of Linac, 3 GeV-RCS, 50 GeV-MR, is under construction at Tokai, Japan. For this accelerator, it is required to minimize the beam loss (typically, lower than 0.1$$sim$$1 W/m at the linac). To achieve the requirement, beam trajectory needs to be controlled with accuracy of some 100 micro-meter. The first stage of the acceleration (up to 181 MeV during the first stage of construction) is done by linac. The beam position monitor (BPM) in the linac utilizes 4 strip-line pickups (50 ohm) on the beam transportation chamber. In this paper, systematic calibration of the BPM is described.

Journal Articles

Pressure-induced structure change of molten KCl

Urakawa, Satoru*; Igawa, Naoki; Umesaki, Norimasa*; Igarashi, Kazuo*; Shimomura, Osamu*; Ono, Hideo

High Pressure Research, 14(4-6), p.375 - 382, 1996/12

 Times Cited Count:6 Percentile:53.84(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Dynamic properties of lithium ions in lithium ceramics

Igawa, Naoki; Ono, Hideo; Nagasaki, Takanori; Ishii, Yoshinobu; Noda, Kenji; Watanabe, H.; Matsuo, Toru*; Igarashi, Kazuo*

Ceramic Transactions, Vol.27, p.135 - 156, 1992/00

no abstracts in English

Journal Articles

A Computer simulation study of the structural similarities between fluoroberyllate and alkaline earth silicate melts

Umesaki, Norimasa*; Ono, Hideo; Igarashi, Kazuo*; *

Journal of Non-Crystalline Solids, 150, p.302 - 306, 1992/00

 Times Cited Count:0 Percentile:0.05(Materials Science, Ceramics)

no abstracts in English

Oral presentation

Study on the radionuclide contamination mechanisms of concrete and the estimation of distribution of radionuclides, 10; Modeling of penetration behavior of Cs and Sr into concrete at turbine building basement of Fukushima Daiichi Nuclear Power Station

Tomita, Sayuri*; Kobayashi, Yutaro*; Haga, Kazuko*; Hosokawa, Yoshifumi*; Yamada, Kazuo*; Aihara, Haruka; Igarashi, Go*; Maruyama, Ippei*

no journal, , 

no abstracts in English

Oral presentation

Basic study on elucidation of the mechanism of concrete contamination and estimation of contamination distribution with radioactive materials; Experimental verification on migration of Cs, Sr, and moisture

Maruyama, Ippei*; Yamada, Kazuo*; Ida, Masaya*; Shibuya, Kazutoshi*; Igarashi, Go*; Koma, Yoshikazu

no journal, , 

no abstracts in English

Oral presentation

21 (Records 1-20 displayed on this page)