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Journal Articles

Evaluation of the bunch-shape monitor for the high-intensity proton beam

Kitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Nemoto, Yasuo*; Morishita, Takatoshi; Oguri, Hidetomo

Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.251 - 253, 2020/09

A bunch-shape monitor (BSM) in the low-energy region is being developed in the J-PARC linac to accelerate the high-intensity proton beam with the low emittance. A highly-oriented pyrolytic graphite (HOPG) was introduced as the target of the BSM to mitigate the thermal loading. The stable measurement of the BSM was realized thanks to the HOPG target, while the tungsten target was broken by the thermal loading from the high-intensity beam. However, since the longitudinal distribution measured with the BSM using the HOPG target was wider than the expected one, the improvement of tuning parameters is necessary for the BSM. The BSM consists of an electron multiplier, a bending magnet, and a radio-frequency deflector, which should be tuned appropriately. Behavior of these components were investigated and tuned. The longitudinal distribution measured with the BSM after the tuning was consistent with the expected one.

Journal Articles

Bunch shape monitor for the high-intensity H$$^{-}$$ beam with 3 MeV using the carbon material

Kitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Moriya, Katsuhiro; Nemoto, Yasuo*; Oguri, Hidetomo

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.51 - 54, 2019/07

The longitudinal measurement and tuning at the beam transport after the RFQ are important to reduce the beam loss and the emittance growth in the J-PARC linac, when the high-intensity H$$^{-}$$ beam of more than 60 mA is supplied. The new bunch shape monitor (BSM) using the carbon-nanotube (CNT) wire is necessary to measure the bunch shape of the high-intensity H$$^{-}$$ beam with 3 MeV, because the CNT wire has a high-temperature tolerance and a small energy deposit. However, when the high voltage was applied to the CNT wire to extract the secondary electron derived, the discharge prevents the power supply from applying the voltage. Therefore, the discharge should be suppressed to measure the bunch shape with stability. Considering the characteristics of the CNT as the emitter, when the length of the CNT wire was short, the high voltage of -10 kV was applied to the CNT wire. The current status and future prospects of the BSM using the CNT wire are reported in this presentation.

Journal Articles

Development of the bunch shape monitor using the carbon-nano tube wire

Kitamura, Ryo; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Moriya, Katsuhiro; Oguri, Hidetomo; Futatsukawa, Kenta*; Miyao, Tomoaki*; Otani, Masashi*; Kosaka, Satoshi*; et al.

Proceedings of 10th International Particle Accelerator Conference (IPAC '19) (Internet), p.2543 - 2546, 2019/06

A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. For example in the J-PARC linac, three BSMs using the tungsten wire are installed at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H$$^{-}$$ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H$$^{-}$$ beam with 3 MeV. The careful attention should be paid to apply the high voltage of $$-$$10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.

Journal Articles

Dynamic accommodation of internal stress and selection of crystallographic orientation relationship in pearlite

Amemiya, Yutaro*; Nakada, Nobuo*; Morooka, Satoshi; Kosaka, Makoto*; Kato, Masaharu*

Tetsu To Hagane, 105(2), p.314 - 323, 2019/02

 Times Cited Count:3 Percentile:37.05(Metallurgy & Metallurgical Engineering)

For deeper understanding of a dynamic accommodation mechanism of internal stress in pearlite originated from the lattice misfit between ferrite and cementite phases, the lattice parameter ratios of cementite were locally analyzed in detail by using the electron backscatter diffraction (EBSD) technique. The EBSD analysis has revealed that lattice parameter ratios of cementite lamellae obviously differ from those of spheroidized cementite particles, which demonstrates that pearlite has a certain amount of internal stress as long as it maintains lamellar structure. The internal stress in pearlite gradually decreased during isothermal holding at 923 K after pearlitic transformation due to interfacial atomic diffusion of iron atoms. However, comparing with theoretical values under Pitsch-Petch orientation relationship, it was understood that large amount of internal stress had been already accommodated upon pearlitic transformation by introduction of misfit dislocations and structural ledges on ferrite/cementite lamellar interfaces. That is, the internal stress of pearlite is dynamically reduced by two different processes; built-in accommodation upon pearlitic transformation and additional time-dependent relaxation after pearlitic transformation. On the other hand, EBSD analysis and neutron diffraction technique gave remarkably different lattice parameters of cementite. From this result, it is concluded that various crystallographic orientation relationships between ferrite and cementite coexist in pearlite. Furthermore, elastic strain energy analysis suggests that the invariant-line criterion on ferrite/cementite interface plays an important role for the selection of orientation relationships in pearlite.

JAEA Reports

Criticality safety evaluation in Tokai Reprocessing Plant; High burn up LWR UO$$_{2}$$ spent fuel and ATR MOX spent fuel

Shirai, Nobutoshi; Inano, Masatoshi; Fukuda, Kazuhito; Kosaka, Ichiro; Yamanaka, Atsushi

JAEA-Research 2011-005, 95 Pages, 2011/03

JAEA-Research-2011-005.pdf:2.46MB

This report presents criticality safety evaluation of each equipment in Tokai Reprocessing Plant for two types of spent fuels, High burn up 4.2% enrichment U oxide spent fuel for light water reactor and U-Pu mixed oxide spent fuel for advanced thermal reactor. As a result, it was confirmed that the equipments were safe enough for two types of the spent fuels from view point of criticality safety of single unit and multiple units.

JAEA Reports

Inventories of high burn up LWR UO$$_{2}$$ spent fuel and ATR MOX spent fuel in Tokai Reprocessing Plant

Shirai, Nobutoshi; Inano, Masatoshi; Fukuda, Kazuhito; Kosaka, Ichiro; Yamanaka, Atsushi

JAEA-Research 2011-004, 60 Pages, 2011/03

JAEA-Research-2011-004.pdf:1.79MB

This report describes calculated results of inventory of radioactivity in the Tokai Reprocessing Plant with calculation code, based on initial conditions and nuclear data library. The inventories were compared with three types of spent fuels, High burn up U oxide for light water reactor, U-Pu mixed oxide for advanced thermal reactor and the design based fuel for Tokai Reprocessing Plant.

JAEA Reports

Study on the method of fault zone survey by use of in-situ hydrogen gas measurement

Kurosawa, Hideki; Ishimaru, Tsuneari; Shimada, Koji; Niwa, Masakazu; Kosaka, Hideki*; Saito, Satoshi*; Ninomiya, Atsushi

JAEA-Research 2009-043, 144 Pages, 2010/01

JAEA-Research-2009-043-01.pdf:8.09MB
JAEA-Research-2009-043-02.pdf:46.22MB

Research on the influence of fault activity on deep geological environments contributes to the reliability of geological disposal systems for HLW. In this study, preliminary test shows that measured value within 1 hour after measurement start is supposed to include hydrogen gas generated by rock fracturing during the drilling of sampling holes and that stored in surrounding disturbed rocks, though the monitoring from a hand-drilled hole is effective for a rapid measurement. We investigated the concentration of hydrogen gas emitted from the Yamasaki fault zone, in southeast Japan. In our survey, the points where high concentrations of hydrogen gas emission was detected were unevenly distributed along the active fault, and in the southeast portion of the study area where small earthquakes frequently occurred.

Oral presentation

Study of small intestine movement by the pressure measurement in a small intestine with using the ileus tube for medical treatments

Narita, Yasuki*; Yoshino, Junji*; Inui, Kazuo*; Wakabayashi, Takao*; Kobayashi, Takashi*; Miyoshi, Hironao*; Kosaka, Toshihito*; Tomomatsu, Yuichiro*; Yamamoto, Satoshi*; Matsuura, Hironao*; et al.

no journal, , 

no abstracts in English

Oral presentation

Development of the bunch shape monitor using the graphene in the medium-energy beam transport of the J-PARC linac

Kitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Nemoto, Yasuo*; Morishita, Takatoshi; Oguri, Hidetomo

no journal, , 

In the J-PARC linac, the optimization of the longitude beam matching in the medium-energy beam transport1 is on-going using the bunch shape monitor (BSM) to improve the beam quality. In the measurement with the BSM, the phase distribution of the beam bunch is indirectly measured using the secondary electron beam produced from the negative hydrogen ion beam. However, when the bunch shape is measured at the center of the beam, it has not been measured yet, because of the limitation of the thermal loading of the secondary electron target. Therefore, the graphene was adopted as the BSM target, because it could resist the high thermal loading. and the performance evaluation was conducted. When the target was set at the center of the beam, the detection of the signal from the graphene target was successful. Therefore, this graphene target can be used for the BSM to measure the high-intensity beam with the low energy.

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