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Journal Articles

Tumor radioresistance caused by radiation-induced changes of stem-like cell content and sub-lethal damage repair capability

Fukui, Roman*; Saga, Ryo*; Matsuya, Yusuke; Tomita, Kazuo*; Kuwahara, Yoshikazu*; Ouchi, Kentaro*; Sato, Tomoaki*; Okumura, Kazuhiko*; Date, Hiroyuki*; Fukumoto, Manabu*; et al.

Scientific Reports (Internet), 12(1), p.1056_1 - 1056_12, 2022/01

 Times Cited Count:6 Percentile:92.29(Multidisciplinary Sciences)

Alive cancer cells after fractionated irradiations with 2 Gy X-rays per day for more than 30 days show clinically relevant radioresistant. Such radioresistance is experimentally interpreted to attributed to the increment of stem-like cell content. However, only an experimental approach cannot clarify the cell responses (DNA damage and cell death induction) of cancer stem cells, so the radioresistant mechanisms remain uncertain. In addition to the conventional cell experiments using radio-resistant cell lines established after fractionated irradiations, in this study we developed a mathematical model (so called integrated microdosimetric-kinetic (IMK) model) explicitly considering cancer stem-like cell content and DNA damage responses and investigated radioresistant mechanisms acquired after fractionated irradiations. The IMK model analysis suggested that the changes of stem-like cell fraction and DNA repair efficiency play important roles of radioresisitance acquired after irradiations. Considering these into the IMK model, we successfully reproduced the experimental survival of various cell lines and various irradiation conditions. This work would contribute to not only the precise understanding of the radioresistant mechanisms induced after irradiation but also predicting curative effects with high precision.

Journal Articles

News from Broader Approach activities, 59

Hoshino, Kazuo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 92(2), p.146 - 147, 2016/02

no abstracts in English

Journal Articles

Operation and commissioning of IFMIF (International Fusion Materials Irradiation Facility) LIPAc injector

Okumura, Yoshikazu; Gobin, R.*; Knaster, J.*; Heidinger, R.*; Ayala, J.-M.*; Bolzon, B.*; Cara, P.*; Chauvin, N.*; Chel, S.*; Gex, D.*; et al.

Review of Scientific Instruments, 87(2), p.02A739_1 - 02A739_3, 2016/02

 Times Cited Count:7 Percentile:35.45(Instruments & Instrumentation)

IFMIF is an accelerator based neutron facility having two set of linear accelerators each producing 125mA/CW deuterium ion beams (250mA in total) at 40MeV. The LIPAc (Linear IFMIF Prototype Accelerator) being developed in the IFMIF-EVEDA project consists of an injector, a RFQ accelerator, and a part of superconducting Linac, whose target is to demonstrate 125mA/CW deuterium ion beam acceleration up to 9MeV. The injector has been developed in CEA Saclay and already demonstrated 140mA/100keV deuterium beam. The injector was disassembled and delivered to the International Fusion Energy Research Center (IFERC) in Rokkasho, Japan, and the commissioning has started after its reassembly 2014; the first beam production has been achieved in November 2014. Up to now, 100keV/120mA/CW hydrogen ion beam has been produced with a low beam emittance of 0.2 $$pi$$.mm.mrad (rms, normalized).

Journal Articles

Measurement of ion species in high current ECR H$$^+$$/D$$^+$$ ion source for IFMIF (International Fusion Materials Irradiation Facility)

Shinto, Katsuhiro; Sen$'e$e, F.*; Ayala, J.-M.*; Bolzon, B.*; Chauvin, N.*; Gobin, R.*; Ichimiya, Ryo; Ihara, Akira; Ikeda, Yukiharu; Kasugai, Atsushi; et al.

Review of Scientific Instruments, 87(2), p.02A727_1 - 02A727_3, 2016/02

 Times Cited Count:8 Percentile:39.44(Instruments & Instrumentation)

Journal Articles

News from Broader Approach activities, 58

Hoshino, Kazuo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 91(12), p.802 - 803, 2015/12

Holding of the 17th IFERC Project Committee (PC), the 16th IFMIF/EVEDA-PC and the progress of the JT-60SA were reported. In the IFERC-PC, total 33 participated including Maisonnier chairperson, JA-EU committee, experts and project members. They reported the status of each activity, discussed the planning of project 2016 and revised plan, and concluded technical advice to the BA Steering Committee (SC). In the IFMIF/EVEDA-PC, total 27 participated including Takatsu chairperson, JA-EU committee, experts and project members. They reported the status of each activity, discussed the planning of project 2016 and revised plan, and the BA-SC recommended the endorsement of the new project plan. In the JT-60SA, a rotary crane for assembly of the troidal field coil has been installed. The disassembly of the constraint jigs of the vacuum vessel which completed 340$$^{circ}$$ assembly has been progressed. 6 high temperature superconductor current leads for the troidal field coils had been delivered from EU.

Journal Articles

News from Broader Approach activities, 57

Hoshino, Kazuo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 91(10), p.700 - 701, 2015/10

The progress of IFMIF Prototype Accelerator in the IFERC site and the Satellite Tokamak (JT-60SA) project were reported. For the IFMIF Prototype Accelerator, two radio frequency (RF) sources of the RF quadrupole accelerator, seven high-voltage power supplies, and distribution cabinets were delivered from the CIEMAT institute in Spain and the installation was started. In the Satellite Tokamak project, the development for long term operation technique of the neutral beam injector has been achieved and thereby confirmed to be feasible for long term operation of JT-60SA. The 340$$^{circ}$$ torus assembly of vacuum vessel of the JT-60SA, which was started from May last year, has been completed. To send out information to the domestic community a major event in the BA activities.

Journal Articles

Present status of the injector for IFMIF Linear Prototype Accelerator (LIPAc)

Shinto, Katsuhiro; Ichikawa, Masahiro; Takahashi, Hiroki; Kondo, Keitaro; Kasugai, Atsushi; Gobin, R.*; Sen$'e$e, F.*; Chauvin, N.*; Ayala, J.-M.*; Marqueta, A.*; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.493 - 495, 2015/09

Development of the prototype accelerator (LIPAc) for the engineering validation of the International Fusion Materials Irradiation Facility (IFMIF) which is an accelerator driven neutron source has been progressed at Rokkasho. The LIPAc is a deuteron linear accelerator consisting of an injector, a radio-frequency quadrupole (RFQ) linac and a superconducting linac. The objective of LIPAc is to produce a CW beam with the energy and current of 9 MeV and 125 mA, respectively. The injector was developed at CEA/Saclay and succeeded to produce CW proton and deuteron beams of 100 keV/140 mA by autumn 2012. After the test at CEA/Saclay, the injector was shipped to the International Fusion Energy Research Centre (IFERC) in Rokkasho, Aomori and started to reassemble from the end of 2013. It was successfully produced proton beams in November 2014 at Rokkasho. While the ion source conditioning was done, the beam test was progressed. In this paper, the present status of the LIPAc injector at Rokkasho with some experimental results will be presented.

Journal Articles

Progress of the high current Prototype Accelerator for IFMIF/EVEDA

Okumura, Yoshikazu; Ayala, J.-M.*; Bolzon, B.*; Cara, P.*; Chauvin, N.*; Chel, S.*; Gex, D.*; Gobin, R.*; Harrault, F.*; Heidinger, R.*; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.203 - 205, 2015/09

Under the framework of Broader Approach (BA) agreement between Japan and Euratom, IFMIF/EVEDA project was launched in 2007 to validate the key technologies to realize IFMIF. The most crucial technology to realize IFMIF is two set of linear accelerator each producing 125mA/CW deuterium ion beams up to 40MeV. The prototype accelerator, whose target is 125mA/CW deuterium ion beam acceleration up to 9MeV, is being developed in International Fusion Research Energy Center (IFERC) in Rokkasho, Japan. The injector developed in CEA Saclay was delivered in Rokkasho in 2014, and is under commissioning. Up to now, 100keV/120mA/CW hydrogen ion beams and 100keV/90mA/CW duty deuterium ion beams are successfully produced with a low beam emittance of 0.21 $$pi$$.mm.mrad (rms, normalized). Delivery of RFQ components will start in 2015, followed by the installation of RF power supplies in 2015.

Journal Articles

News from Broader Approach activities, 56

Hoshino, Kazuo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 91(8), p.561 - 562, 2015/08

The new construction of Joint Research Building for the DEMO R&D at IFERC, progress of the IFMIF Prototype Accelerator and the Satellite Tokamak (JT-60SA) project were reported. The Joint Research Building processing the construction as a new place where carry out a part of project for the DEMO R&D in the rest of the BA activity period and it mainly consists of the laboratory/material testing room for the material evaluation and Be production room for handling of the metal beryllium. For the IFMIF Prototype Accelerator, completed the repairs and test run of the Interlock, successful of the continuity rated proton beam, then after setting of the radiation control area, successful production of the deuterium ion beam. For the JT-60SA, the installation of a Helium refrigerator which is one of the world's largest and a He buffer tank have been completed. The 4th Research Coordination meeting was held and they discussed the research plan and theme for the experiment proposal of JT-60SA.

Journal Articles

News from Broader Approach activities, 55

Hoshino, Kazuo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 91(6), p.430 - 431, 2015/06

Holding of the 16th BA Steering Committee and progress of the Satellite Tokamak (JT-60SA) project were reported. There were 33 participants for the 16th BA Steering Committee, including 3 committee members and 10 specialists from EU, 4 committee and 11 specialists from JP, each project leaders and project committee chair persons, and they approved for update of the 2014 Annual Report and the Work Plan of IFMIF/EVEDA, the IFERC and the Satellite Tokamak project. In the construction of JT-60SA, the component carry-in from EU and the assembly has been progressed steadily in JP. To announce for these progressing, a ceremony was held and 200 people concerned in EU-JP attended. The 22nd JT-60SA Technical Coordination Meeting was held. 73 people EU-JP joined and had discussion regarding the design, status of production, examination of assembly and the integrate operation in the future. To send out information to the domestic community a major event in the BA activities.

Journal Articles

News from Broader Approach activities, 54

Ishii, Yasutomo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 91(4), p.296 - 297, 2015/04

Holding of the IFMIF/EVEDA Project Committee, IFERC Project Committee and IFERC-CSC Workshop and progress of the JT-60SA were reported. For the 15th IFMIF/EVEDA-PC, 31 were present and they discussed project plan etc. and concluded technical advice to the BA Steering Committee. For the 16th IFERC-PC, 32 were present and they discussed the 2014 annual report and revision of project plan and concluded technical advice to the BA-SC. For the IFERC-CSC Workshop, 39 Domestic Researcher were attended and they reported the result of each project and exchanged views in utilizing CSC. In the JT-60SA, in parallel with the vacuum vessel assembly, preparation of the peripheral equipment and related building have been progressed steadily. To send out information to the domestic community a major event in the BA activities.

Journal Articles

News from Broader Approach activities, 53

Ishii, Yasutomo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 91(2), p.161 - 162, 2015/02

Success of the first beam of injector for IFMIF prototype accelerator, accomplishment of liquid Lithium Target validation test of the IFMIF/EVEDA and the progress of Satellite Tokamak (JT-60SA) were reported. The IFMIF/EVEDA project are performed in International Fusion Energy Research Center at Rokkasho under the BA agreement, installation and adjustment of injector for IFMIF accelerator were completed and the adjustment beam test has started from Nov. 2014. For the engineering validation test, formability of the Lithium Target which become the neutron source, the Lithium Test Loop of real scale was fabricated in Oarai and test has been conducted for 2 years. At the end of Oct. 2014, made an exceeding achievement and successfully concluded. In the construction of JT-60SA at Naka, the design of each part has been performing with the 3D CAD soft CATIA. The update with previous state discloses on JT60-SA HP. To disseminate information to the domestic community a major event in the BA activities.

Journal Articles

News from Broader Approach activities, 52

Ishii, Yasutomo; Matsunaga, Go; Okumura, Yoshikazu

Purazuma, Kaku Yugo Gakkai-Shi, 90(12), p.827 - 828, 2014/12

Holding of the 15th BA Steering Committee, the 14th IFMIF/EVADA business meeting, the 15th IFERC business meeting and the progress of the Satellite Tokamak (JT-60SA) plan were reported. There were participation of 3 committee members and 8 specialists from EU side and also 30 people which is 4 committees, 7 specialists, each project leaders and project committee chair persons, for the 15th BA Steering Committee and approved for the 2015 Work Plan of IFMIF/EVADA project, the IFERC project and the Satellite Tokamak.6 committees (3 EU side, 3 Japan side), 12 specialists (5 EU, 7 JP) and 8 members of IFMIF/EVADA team, for the 14th IFMIF/EVADA meeting and progress of the each activities were reported.6 committees (3 EU, 3 JP), 16 specialists (9 EU, 7 JP) and 9 members of IFERC team, for the 15th IFERC meeting and reported on progress and discussed about the 2015 Work Plan. In the progress of the JT-60SA plan, assembly work of vacuum chamber is proceeding smoothly in the JT-60 main body room.

Journal Articles

Status quo of the injector for the IFMIF/EVEDA prototype accelerator

Shinto, Katsuhiro; Ichikawa, Masahiro; Takahashi, Yasuyuki*; Kubo, Takashi*; Tsutsumi, Kazuyoshi; Kikuchi, Takayuki; Kasugai, Atsushi; Sugimoto, Masayoshi; Gobin, R.*; Girardot, P.*; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1009 - 1012, 2014/10

The prototype accelerator is being developed as an engineering validation for the International Fusion Materials Irradiation Facility (IFMIF) equipped with an accelerator-driven-type neutron source for developing fusion reactor materials. This prototype accelerator is a deuteron linear accelerator consisting of an injector, an RFQ, a superconducting linac and their auxiliaries. It aims to produce a CW D$$^+$$ beam with the energy and current of 9 MeV/125 mA. The injector test was completed at CEA/Saclay in 2012 for producing a CW H$$^+$$ beam and a CW D$$^+$$ beam with the energy and current of 100 keV/140 mA. After the beam test at CEA/Saclay, the injector was transported to the International Fusion Energy Research Centre (IFERC) located in Rokkasho, Aomori, Japan. In the end of 2013, installation of the injector was started at IFERC for the injector beam test beginning from summer 2014 in order to obtain better beam qualities to be satisfied with the injection and acceleration of the following accelerators. In this paper, some results of the injector beam test performed at CEA/Saclay and the status quo of the installation of the injector at IFERC are presented.

Journal Articles

Present status of the high current prototype accelerator for IFMIF/EVEDA

Okumura, Yoshikazu

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.194 - 198, 2014/10

International Fusion Materials Irradiation Facility (IFMIF) is one of the major facilities in fusion program to irradiate and characterize the fusion materials under intense neutron field. Under the framework of Broader Approach (BA) agreement between Japan and Euratom, Engineering Validation and Engineering Design Activities (EVEDA) launched in 2007 in Japan to validate the key technologies to realize IFMIF. The most critical technology to realize IFMIF is two set of linear accelerators each producing 125mA/CW deuterium ion beams up to 40MeV. The prototype accelerator being developed in EVEDA consists of an injector, a RFQ accelerator, and a superconducting linac, whose target is to produce 125mA/CW deuterium ion beams up to 9MeV. The injector has been delivered to International Fusion Energy Research Center (IFERC) in Rokkasho, Japan, where all the accelerator components will be assembled and operated to validate the accelerator technologies required for IFMIF.

Journal Articles

Development of a high current H$$^{-}$$ ion source for cyclotrons

Eto, Haruhiko*; Aoki, Yasushi*; Mitsubori, Hitoshi*; Arakawa, Y.*; Mitsumoto, Toshinori*; Yajima, S.*; Sakuraba, Junji*; Kato, Takanori*; Okumura, Yoshikazu

Review of Scientific Instruments, 85(2), p.02B107_1 - 02B107_3, 2014/02

 Times Cited Count:10 Percentile:43.09(Instruments & Instrumentation)

High current hydrogen negative ion source is required to increase the accelerated beam current of the cyclotrons for many medical applications such as cancer therapy and medical radioisotope production. A new negative ion source has been designed and fabricated. The ion source is a multi-cusp type. Optimization of the ion source is in progress, such as the optimization of the magnetic filter which prevents high temperature electrons from entering into the negative ion production region, improvement of the extraction electrode's shape and configuration of dipole magnets etc. A small quantity of Cs has been introduced into the ion source to enhance the negative ion beam current. The ion source produced 16mA of DC hydrogen negative ion beam with the Cs-seeded operation at a low arc discharge power of 2.8 kW.

Journal Articles

Present status and achievements of Broader Approach activities

Okumura, Yoshikazu

Fusion Science and Technology, 64(2), p.86 - 95, 2013/08

 Times Cited Count:3 Percentile:25.83(Nuclear Science & Technology)

Five years have passed since the Broader Approach (BA) activities launched in 2007 under the framework of collaboration between Japan and EURATOM. In a DEMO R&D Building in the IFERC site in Rokkasho, tritium facility, beryllium treatment facility, and microscopic measurement facility were installed in 2010. The tritium was delivered in March 2012. A supercomputer for the simulation of fusion plasmas and other application of the BA activities starts operation in January 2012. It demonstrated LINPAC speeds of more than 1.2 PFlops. Accelerator components for IFMIF/EVEDA are being fabricated in European institutes. The injector is now under commissioning in CEA Saclay, and will be delivered in Rokkasho in March 2013. The IFMIF/EVEDA lithium test loop was constructed in Oarai, Japan, in 2011 and starts operation in May 2012. The JT-60 tokamak is being disassembled and upgraded to an advanced superconducting tokamak JT-60SA. Manufacturing of tokamak components is now in progress.

Journal Articles

Research facilities for International Fusion Energy Research Centre of Broader Approach Activities at Rokkasho

Ohira, Shigeru; Utsumi, Shigeo*; Kubo, Takashi; Yonemoto, Kazuhiro; Kasuya, Kenichi; Ejiri, Shintaro; Kimura, Haruyuki; Okumura, Yoshikazu

Journal of Plasma and Fusion Research SERIES, Vol.9, p.665 - 669, 2010/08

Under the Agreement Between the Government of Japan and the EURATOM for the Joint Implementation of the Broader Approach Activities (BA Activities) in the Field of Fusion Energy Research, JAEA develop a new site at Rokkasho-mura in Aomori prefecture of Japan as the Japanese Implementing Agency. In this new site, two of the three projects of the BA Activities are to be implemented, namely, International Fusion Energy Research Center (IFERC) Project and International Fusion Material Irradiation Facility/Engineering Validation and Engineering Design Activity (IFMIF/EVEDA) Project. In March 2009, the Administration and Research Building was completed, and the other research facilities; CSC&REC Building, DEMO R&D Building and IFMIF/EVEDA Accelerator Building will be completed in March 2010. In this presentation, the specifications and construction schedule of the individual research buildings will be presented, especially special features of the IFMIF/EVEDA Accelerator Building.

Journal Articles

Values of construction of IFMIF accelerator prototype and targeted issues

Sugimoto, Masayoshi; Garin, P.*; Vermare, C.*; Shidara, Hiroyuki; Kimura, Haruyuki; Suzuki, Hiromitsu; Ohira, Shigeru; Okumura, Yoshikazu; Mosnier, A.*; Facco, A.*; et al.

Kasokuki, 7(2), p.110 - 118, 2010/07

International Fusion Materials Irradiation Facility (IFMIF) is an accelerator-based neutron irradiation facility dedicated for development of fusion materials. Engineering Validation and Engineering Design Activities (EVEDA) phase of IFMIF project has been initiated in June 2007 and a prototype of the IFMIF accelerator (40 MeV - 125 mA CW Deuteron) is under construction in Rokkasho, Aomori. The target of the prototype is 9 MeV - 125 mA CW beam operation, which is full scale prototyping up to the first tank of superconducting linac section. In this report, the major technical specifications and issues of this extremely high-power machine are overviewed and expected results through operation in future are summarized.

Journal Articles

Commissioning of the IFMIF/EVEDA accelerator prototype; Objectives & plans

Vermare, C.*; Garin, P.*; Shidara, H.*; Beauvais, P. Y.*; Mosnier, A.*; Ibarra, A.*; Heidinger, R.*; Facco, A.*; Pisent, A.*; Maebara, Sunao; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.777 - 779, 2010/05

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