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Wada, Motoi*; Shinto, Katsuhiro; Shibata, Takanori*; Sasao, Mamiko*
Review of Scientific Instruments, 91(1), p.013330_1 - 013330_5, 2020/01
Times Cited Count:4 Percentile:27.22(Instruments & Instrumentation)The ions are extracted from an ion source through a plasma sheath where a low frequency electromagnetic induction drives transport of charged particles including the target ions. High frequency alternating current commonly excites plasmas in sources for negative hydrogen (H) ions at a frequency in the MHz range. A high-speed beam current monitor system coupled to a narrow entrance slit enabled the investigation of the special distribution of the AC component intensity of the H ion beam extracted from an ion source driven by a 2 MHz radio frequency (RF) power. The distribution showed a smaller oscillation of the beam at the center.
Shinohara, Koji; Ishii, Keiichi*; Ochiai, Kentaro; Baba, Mamoru*; Sukegawa, Atsuhiko; Sasao, Mamiko*; Kitajima, Sumio*
Review of Scientific Instruments, 85(11), p.11E823_1 - 11E823_4, 2014/11
Times Cited Count:0 Percentile:0.01(Instruments & Instrumentation)Kawano, Yasunori; Itami, Kiyoshi; Kawahata, Kazuo*; Kusama, Yoshinori; Sasao, Mamiko*; Peterson, B.*; Mase, Atsushi*
Purazuma, Kaku Yugo Gakkai-Shi, 90(2), P. 164, 2014/02
no abstracts in English
Shinohara, Koji; Ishii, Keiichi*; Ochiai, Kentaro; Baba, Mamoru*; Sasao, Mamiko*; Kitajima, Sumio*
Plasma and Fusion Research (Internet), 8, p.1402144_1 - 1402144_9, 2013/11
Sasao, Mamiko*; Ishikawa, Masao; Yuan, G.*; Patel, K.*; Jakhar, S.*; Kashchuk, Y.*; Bertalot, L.*
Plasma and Fusion Research (Internet), 8(Sp.1), p.2402127_1 - 2402127_3, 2013/09
Fusion power output of ITER is measured by a group of neutron flux monitors combined with a neutron activation system and neutron profile monitors. These systems should be absolutely calibrated by use of DD/DT generators moving inside the ITER vacuum vessel (in-situ calibration). Each neutron monitor has a limited measurement range of emission rate, but the ranges are connected by cross-calibration using the ITER plasma with at least one decade overlapping. The over all dynamic range covered by the group of neutron flux monitors is 10 n/sec to 10 n/sec. Effects of vertical/radial movement of plasma on the measurement accuracy were reviewed. It was found that cross-calibration using specially planned jog shots, and a vertical neutron camera is important to minimize the inaccuracy caused by the plasma movement.
Itami, Kiyoshi; Kawano, Yasunori; Kawahata, Kazuo*; Kusama, Yoshinori; Sasao, Mamiko*; Peterson, B.*; Mase, Atsushi*
Purazuma, Kaku Yugo Gakkai-Shi, 89(9), P. 638, 2013/09
no abstracts in English
Kiriyama, Hiromitsu; Shimomura, Takuya; Sasao, Hajime; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Pirozhkov, A. S.; Mori, Michiaki; Fukuda, Yuji; et al.
Optics Letters, 37(16), p.3363 - 3365, 2012/08
Times Cited Count:39 Percentile:85.67(Optics)We demonstrate the temporal contrast enhancement in a petawatt-class Ti:sapphire chirped-pulse amplification (CPA) laser system. An extra saturable absorber, introduced downstream a low gain optical parametric chirped-pulse amplification (OPCPA) preamplifier, has improved the temporal contrast in the system to 1.410 on the sub-nanosecond time scale at 70 TW power level. We have achieved 28 J of uncompressed broadband output energy with this system, indicating the potential for reaching peak powers near 600 TW.
Ogura, Koichi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Tanimoto, Tsuyoshi*; Sagisaka, Akito*; Esirkepov, T. Z.; Kando, Masaki; Shizuma, Toshiyuki; Hayakawa, Takehito; Kiriyama, Hiromitsu; et al.
Optics Letters, 37(14), p.2868 - 2870, 2012/07
Times Cited Count:83 Percentile:95.79(Optics)Using high contrast (10:1) and high intensity (10 W/cm) laser pulse with the duration of 40 fs from OPCPA/Ti:Sapphire laser, a 40 MeV proton bunch is obtained, which is a record for laser pulse with energy less than 10 J. The efficiency for generation of protons with kinetic energy above 15 MeV is 0.1%.
Hayashi, Nobuhiko; Ide, Shunsuke; Suzuki, Takahiro; Itami, Kiyoshi; Kawano, Yasunori; Sasao, Mamiko*; Kusama, Yoshinori
Purazuma, Kaku Yugo Gakkai-Shi, 88(7), p.392 - 393, 2012/07
no abstracts in English
Ogura, Koichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Yogo, Akifumi; Nishiuchi, Mamiko; Orimo, Satoshi; Sagisaka, Akito; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; et al.
Japanese Journal of Applied Physics, 51(4), p.048003_1 - 048003_2, 2012/04
Times Cited Count:2 Percentile:8.87(Physics, Applied)A proton beam driven by a repetitive high-intensity-laser is utilized to induce a Li(p,n)Be nuclear reaction. The total activity of Be are evaluated by two different methods. The activity obtained measuring the decay -rays after 1912 shots at 1 Hz is 1.70.2 Bq. This is in good agreement with 1.60.3 Bq evaluated from the proton energy distribution measured using a time-of-flight detector and the nuclear reaction cross-sections. We conclude that the production of activity can be monitored in real time using the time-of-flight-detector placed inside a diverging proton beam coupled with a high-speed signal processing system.
Shinto, Katsuhiro; Wada, Motoi*; Nishida, Tomoaki*; Demura, Yasuhiro*; Sasaki, Daichi*; Tsumori, Katsuyoshi*; Nishiura, Masaki*; Kaneko, Osamu*; Kisaki, Masashi*; Sasao, Mamiko*
AIP Conference Proceedings 1390, p.675 - 683, 2011/09
Times Cited Count:0 Percentile:0.19(Physics, Atomic, Molecular & Chemical)Asakura, Nobuyuki; Ashikawa, Naoko*; Ueda, Yoshio*; Ono, Noriyasu*; Tanabe, Tetsuo*; Nakano, Tomohide; Masuzaki, Suguru*; Itami, Kiyoshi; Kawano, Yasunori; Kawahata, Kazuo*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 87(7), p.485 - 486, 2011/07
no abstracts in English
Yogo, Akifumi; Maeda, Takuya; Hori, Toshihiko; Sakaki, Hironao; Ogura, Koichi; Nishiuchi, Mamiko; Sagisaka, Akito; Kiriyama, Hiromitsu; Okada, Hajime; Kanazawa, Shuhei; et al.
Applied Physics Letters, 98(5), p.053701_1 - 053701_3, 2011/02
Times Cited Count:98 Percentile:94.24(Physics, Applied)Ishii, Keiichi*; Shinohara, Koji; Ishikawa, Masao; Baba, Mamoru*; Isobe, Mitsutaka*; Okamoto, Atsushi*; Kitajima, Sumio*; Sasao, Mamiko*
Review of Scientific Instruments, 81(10), p.10D334_1 - 10D334_3, 2010/10
Times Cited Count:6 Percentile:30.81(Instruments & Instrumentation)Sasao, Mamiko*; Bertalot, L.*; Ishikawa, Masao; Popovichev, S.*
Review of Scientific Instruments, 81(10), p.10D329_1 - 10D329_3, 2010/10
Times Cited Count:16 Percentile:57.28(Instruments & Instrumentation)Accuracy of 10% is demanded to the absolute fusion measurement on ITER. To achieve this accuracy, a functional combination of several types of neutron measurement sub-system, cross calibration among them, and in-situ calibration, are needed. Neutron transport calculations show that a suitable calibration source is a DT/DD neutron generator of source strength higher than 10 n/s for DT and 10 n/s for DD. It will take 8 weeks at the minimum with this source to calibrate flux monitors, profile monitors, and the activation system.
Kawano, Yasunori; Sasao, Mamiko*; Mase, Atsushi*; Kawahata, Kazuo*; Kusama, Yoshinori; Peterson, B.*; Itami, Kiyoshi
Purazuma, Kaku Yugo Gakkai-Shi, 86(9), P. 552, 2010/09
no abstracts in English
Sakaki, Hironao; Nishiuchi, Mamiko; Hori, Toshihiko; Bolton, P.; Yogo, Akifumi; Ogura, Koichi; Sagisaka, Akito; Pirozhkov, A. S.; Orimo, Satoshi; Kondo, Kiminori; et al.
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.312 - 315, 2010/08
The beam transport test is carried out through the test beam line of the laser-driven proton accelerator which consists of the phase rotation cavity, PMQ, and bending magnet. The laser system used is J-KAREN at JAEA. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code by assuming relatively low initial current of the proton beam. The most probable explanation for this is the space charge neutralization by the laser-plasma-electrons.
Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.
Physical Review Special Topics; Accelerators and Beams, 13(7), p.071304_1 - 071304_7, 2010/07
Times Cited Count:25 Percentile:79.26(Physics, Nuclear)A laser-driven repetition-rated 1.9 MeV proton beam line composed of permanent quadrupole magnets (PMQs), a radio frequency (rf) phase rotation cavity, and a tunable monochromator is developed to evaluate and to test the simulation of laser-accelerated proton beam transport through an integrated system for the first time. In addition, the proton spectral modulation and focusing behavior of the rf phase rotationcavity device is monitored with input from a PMQ triplet. In the 1.9 MeV region we observe very weakproton defocusing by the phase rotation cavity. The final transmitted bunch duration and transverse profile are well predicted by the PARMILA particle transport code. The transmitted proton beam duration of 6 ns corresponds to an energy spread near 5% for which the transport efficiency is simulated to be 10%. The predictive capability of PARMILA suggests that it can be useful in the design of future higher energy transport beam lines as part of an integrated laser-driven ion accelerator system.
Shinto, Katsuhiro; Wada, Motoi*; Kaneko, Osamu*; Tsumori, Katsuyoshi*; Nishiura, Masaki*; Sasao, Mamiko*; Kisaki, Masashi*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.999 - 1001, 2010/05
We propose a negative ion beam probe system as a new scheme to diagnose beam profile of high power positive ion beams. Two RF linacs of IFMIF have to drive the neutron source by providing continuous-wave (CW) positive deuterium ion beams with the intensity of 125 mA each at the beam energy of 40 MeV. During the CW beam operations, the extreme intensity of the beam and the severe radiation levels make the beam diagnostics with conventional techniques in the transport lines terribly difficult. A beam of negative ions liable to lose the additional electron at the occasion of impact with a high energy particle can work as a probe to measure the positive ion beam profile. On possible configuration to achieve high intensity beam profile measurement is to inject a negative ion probe beam into the target beam perpendicularly, and measure the attenuation of the negative ion beam by beam-beam interaction at each position. We have started an experimental study for the proof-of-principle of the new beam profile monitoring system. The paper presents the status quo of this beam profile monitor system development and the prospects to apply the system to the IFMIF beam line controls.
Nishiuchi, Mamiko; Sakaki, Hironao; Hori, Toshihiko; Bolton, P.; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Mori, Michiaki; Orimo, Satoshi; Pirozhkov, A. S.; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.88 - 90, 2010/05
The concept of a compact ion particle accelerator has become attractive in view of recent progress in laser-driven ion acceleration. We report here the recent progress in the laser-driven proton beam transport at the Photo Medical Research Center (PMRC) at JAEA, which is established to address the challenge of laser-driven ion accelerator development for ion beam cancer therapy.