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Oral presentation

Development of LLRF control system for J-PARC RCS

Tamura, Fumihiko; Schnase, A.; Yamamoto, Masanobu; Nomura, Masahiro; Yoshii, Masahito*; Omori, Chihiro*; Takagi, Akira*; Hara, Keigo*; Anami, Shozo*; Ezura, Eiji*

no journal, , 

The J-PARC Rapid cycling synchrotron(RCS) requires a verystable and precise low level RF(LLRF) control system to handle theultra-high proton beam currents. The MA-loaded low-Q cavities for theRCS are driven by the superposition of the dual-harmonic RF signal forboth the acceleration and the longitudinal bunch shaping. We employ afull-digital system based on direct digital synthesis(DDS). Themulti-harmonic RF signals generated by the DDS are easily synchronizedwithout PLLs. We describe the design and the structure of the LLRFblocks. The common feedback loops are used for the stabilizing thebeam orbit and phase as well as the RF voltages of the cavity. Theheavy beam loading effect is compensated by using the beam feedforwardmethod. We also present the test results of the recently manufacturedmodules.

Oral presentation

Effect of stress history on creep behavior of rock

Hashiba, Kimihiro; Matsui, Hiroya; Sato, Toshinori; Seno, Yasuhiro

no journal, , 

In this study, multi-stage creep tests were conducted with tuff and siliceous rock. The creep stresses of each stage and the duration of the first stage were variable, and the effect of the stress history on creep behavior was examined. It was found that the primary creep strain rate might be decreased by the stress history. In particular, the effect of the stress history was notable after the first stage with the large creep stress and the long duration. It was also found that the effect of the stress history of siliceous rock was larger than that of tuff.

Oral presentation

Radiation processing of polymer

Tamada, Masao

no journal, , 

In the radiation processing of polymer, graft polymerization and crosslinking induced by high energy radiation can lead the modification of polymer materials. Metal adsorbent synthesized by graft polymerization was applied to the removal of cadmium from scallop processing and the recovery of uranium from seawater. Crosslinking was available to improve the thermal properties of biodegradable polymer such as poly-lactic acid.

Oral presentation

Application of positron imaging method for plant breeding

Matsuhashi, Shimpei

no journal, , 

no abstracts in English

Oral presentation

Study of cellular radiation response using heavy-ion microbeams

Kobayashi, Yasuhiko

no journal, , 

no abstracts in English

Oral presentation

Effect of the thermomechanical treatment conditions onto characteristics of chromium-zirconium copper after the solution treatment

Hada, Kazuhiko; Nishi, Hiroshi; Hirose, Takanori; Mori, Kensuke; Aoki, Shoji*; Wada, Masahiko*; Yamamichi, Tetsuo*

no journal, , 

Chromium-zirconium copper as precipitation hardened copper alloy is examined as one of the structural materials used for the ITER in vacuum vessel components. The process that consists of a thermomechanical treatments series of the solution treatment with rapid cooling to obtain the supersaturated solid solution and the aging treatment etc., is adopted in order to obtain the demanded high strength in manufacturing of this alloy material. However, as this alloy is precipitation hardened copper alloy, it is concerned that the great change in the strength characteristic is caused by the thermomechanical treatments conditions, especially the difference of the quenching cooling rate after the solution treatment in manufacturing. In this research, the influence of the quenching cooling rate condition after the solution treatment and the other conditions on this copper alloy was investigated by measuring the tensile test properties of the specimens that are prepared by treatments with some quenching cooling rate conditions after the solution treatment and aging treatment. One of the typical results from this study is that, for the quenching cooling rate after the solution treatment, it was understood that the cooling rate change from 1 to 10$$^{circ}$$C/s causes the great growth in the tensile strength. Therefore, when this alloy component is manufactured by heat history process like HIP process and needed to be treated solution treatment to be use for the structural component, it is important to guarantee the strength of the product by checking the quenching cooling rate after the solution treatment.

Oral presentation

Study on redox equilibrium of U$$^{4+}$$/U$$^{3+}$$ in molten NaCl-2CsCl

Nagai, Takayuki; Uehara, Akihiro*; Shirai, Osamu*; Yamana, Hajimu*

no journal, , 

no abstracts in English

Oral presentation

Analyses of DNA complex and crystallization of the DNA repair promoting protein PprA derived from Deinococcus Radiodurance

Adachi, Motoyasu; Tamada, Taro; Sato, Katsuya*; Narumi, Issei; Kuroki, Ryota

no journal, , 

The resistance of Deinococcus radiodurans to $$gamma$$-ray is 1000 times higher than that of human cells. PprA is the novel protein which promotes repairing DNA, and play a key role in the ability to resist to the radiation. The characterization of PprA have showed: (1) that the expression of PprA is controlled under another novel protein of PprI (2) that PprA promotes ligase reaction: (3) that pprA exhibits the ability to bind on DNA. In this study, our objective is the crystal structure analysis of PprA to reveal its structure-function relationships and for application as genetic and clinical tools. Here, we constructed the E. coli expression and purification system of PprA. Using the purified PprA, some small crystals in size were obtained after screening of conditions for crystalization. Beased on the analyses of DNA-PprA interaction, we showed that 280 molecules of PprA at least can bind on a DNA molecule of pUC19 plasmid (2686bp). In addition, we indicated that several DNA-PprA complexes may form higher complex, when DNA includes terminal end or nick (the cleaved part on a DNA strand). These results are important knowledge in molecular assembly and function of PprA.

Oral presentation

Positronium formation in SiO$$_{2}$$

Komuro, Yo; Hirade, Tetsuya; Suzuki, Ryoichi*; Odaira, Toshiyuki*; Muramatsu, Makoto*

no journal, , 

The annihilation $$gamma$$ rays from the para-pojitoronium (p-Ps) state gives narrower Doppler broadening. The broader Doppler broadening was observed at very young age region that is mainly from the annihilation process of p-Ps. It was explained by the delayed Ps slowing down and the delayed Ps formation. We have successfully obtained the experimental evidence of the delayed Ps formation.

Oral presentation

Temporal variation in performance of iodine-129 collecting media for a long-term and large-volume sampling

Miyauchi, Toru; Koarashi, Jun; Mikami, Satoshi; Kozawa, Tomoyasu*; Yokota, Tomokazu*; Isaka, Keisuke*; Akiyama, Kiyomitsu

no journal, , 

no abstracts in English

Oral presentation

Direct observation of superoxide radicals produced in water by 70MeV/u Kr ion irradiations

Taguchi, Mitsumasa; Baldacchino, G.*; Pin, S.*; Vigneron, G.*; Hichel, B.*; Kojima, Takuji

no journal, , 

no abstracts in English

Oral presentation

Airborne radioiodine monitoring technique without interference of Krypton-85 in nuclear fuel reprocessing operation

Mikami, Satoshi; Miyauchi, Toru; Koarashi, Jun; Kozawa, Tomoyasu*; Yokota, Tomokazu*; Isaka, Keisuke*; Akiyama, Kiyomitsu

no journal, , 

no abstracts in English

Oral presentation

Development of soft X-ray flat field laminar-type holographic gratings

Koike, Masato; Sano, Kazuo*; Sasai, Hiroyuki*

no journal, , 

The flat field spectrographs are coming into the limelight once again taking the advantages of the rapid progress of the solid state imaging devices, and the needs of the ultra-high speed simultaneous measurements reaching to femto- or atto- seconds. A typical soft X-ray spectrograph employs a mechanically ruled varied-line-spacing spherical grating. We have also developed a holographic grating for this spectrograph,and spectrographs of this type are used in a variety of research areas. However it utilizes a pseudo-flat image plane near the point of inflection of the focal curve called lemniscates. Therefore the obtainable resolving power is limited and it is difficult to reach to several thousands. Also it is still a challenging subject to extend to the multi-keV region due to the degradation of the diffraction efficiency. We describe the recent progress of the soft X-ray flat field holographic grating spectrographs, a design study of a high resolution spectrograph using a varied-line-spacing plane grating, and the possible options to extend them to the multi-keV region.

Oral presentation

Structure and phase transition of Sn/Ge(111) surface studied by reflection high-energy positron diffraction

Fukaya, Yuki; Kawasuso, Atsuo; Ichimiya, Ayahiko

no journal, , 

no abstracts in English

Oral presentation

Synthesis of proton-conducting membranes by radiation-induced grafting; Influence of base materials

Asano, Masaharu; Chen, J.; Yamaki, Tetsuya; Yoshida, Masaru

no journal, , 

To prepare proton-conducting membranes with an excellent mechanical characteristic, a mixture of styrene and divinylbenzene was grafted into various base materials such as CF2-derivatives (PTFE, PFA and FEP) and CF2/CH2-derivatives (ETFE and PVDF). It was found that the introduction of graft-chains into CF2/CH2-derivatives was easier compared with that of CF2-derivatives. These derivatives that introduced the graft-chains were then sulfoanted, in order to determine the tensile strength, as a resulting of higher tensile strength for sulfonated CF2/CH2-derivatives

Oral presentation

Dependence of the beam uniformity on the magnetic filter strength in a large Cs-seeded negative ion source for ITER

Seki, Takayoshi; Hanada, Masaya; Tobari, Hiroyuki; Inoue, Takashi; Takado, Naoyuki*; Mizuno, Takatoshi*; Hatayama, Akiyoshi*; Kashiwagi, Mieko; Taniguchi, Masaki; Watanabe, Kazuhiro; et al.

no journal, , 

no abstracts in English

Oral presentation

Investigation on the heavy fermion superconductors by the ac heat capacity measurement

Tateiwa, Naoyuki; Haga, Yoshinori; Matsuda, Tatsuma; Ueda, Taiki*; Thamizhavel, A.*; Nakashima, Miho*; Takeuchi, Tetsuya*; Settai, Rikio*; Onuki, Yoshichika; Knebel, G.*; et al.

no journal, , 

We have developed the system for the heat capacity measurement by the thermocouple in order to study the high pressure physical properties of the rare earth and actinide compounds. In this talk, we would like to show our system and discuss our recent results on the heavy fermion superconductors CePt$$_3$$Si and UIr. It is noted that the superconductivity of UIr was found by our group. There is no inversion center in crystal structures of both compounds. The superconductivity of both compounds might be the novel type. In the case of CePt$$_3$$Si, the antiferromagnetic phase is strongly suppressed by the applied pressure and disappears above 0.6 GPa, while the superconducting phase exists in the wide pressure region up to 1.5 GPa. It is found that the overall feature of the pressure phase diagram is different from those of other heavy fermion superconductors. In the case of UIr, it is suggested by the resistivity measurement under pressures that there exists multiple ferromagnetic phases in the high pressure region. We investigated the pressure phase diagram of UIr from the thermodynamic point of view. We discuss the relation between the superconductivity and magnetism in UIr.

Oral presentation

The Large-scale numerical analysis of nuclear power plant in distributed computational environments

Minami, Takahiro; Matsubara, Hitoshi; Yamagishi, Nobuhiro; Hasegawa, Yukihiro; Aoyagi, Tetsuo; Nakajima, Norihiro; Tani, Masayuki

no journal, , 

no abstracts in English

Oral presentation

Development of computational dosimetry system for particle radiotherapy

Kumada, Hiroaki; Yamamoto, Kazuyoshi

no journal, , 

no abstracts in English

Oral presentation

Geographical distribution of plutonium derived from the Nagasaki atomic bomb

Kokubu, Yoko; Yasuda, Kenichiro; Magara, Masaaki; Miyamoto, Yutaka; Sakurai, Satoshi; Usuda, Shigekazu; Yoshikawa, Shusaku*; Yamazaki, Hideo*

no journal, , 

no abstracts in English

33297 (Records 1-20 displayed on this page)