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Shobuda, Yoshihiro; Chin, Y. H.*; Takata, Koji*; Toyama, Takeshi*; Nakamura, Keigo*
Proceedings of 57th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB 2016) (Internet), p.523 - 528, 2016/08
In J-PARC MR, there is a concern that electron cloud instabilities may appear and limit the beam current at future higher power operations. For the case, we have developed a wider-band beam position monitor by deforming the electrode shapes. The modification of the electrode can be done without significant enhancement of the beam coupling impedance. For typical electrode shapes, we show the coupling impedances as well as the frequency responses of the electrodes.
Shobuda, Yoshihiro; Chin, Y. H.*; Takata, Koji*; Toyama, Takeshi*; Nakamura, Keigo*
Physical Review Accelerators and Beams (Internet), 19(2), p.021003_1 - 021003_15, 2016/02
Times Cited Count：1 Percentile：11.94(Physics, Nuclear)The frequency domain performance of a stripline beam position monitor depends largely on the longitudinal shape of its electrode. To attain a good impedance matching along the electrode, it needs to be precisely bent down toward its downstream in proportion to its width. In this report, we first propose a triangle electrode for easy fabrication and set-up. Theoretical and simulation results show that the simple triangle electrode has a remarkably flatter frequency response than the rectangle one. The frequency response, in particular at high frequencies, can be further improved by attaching an "apron" plate, perpendicular to the upstream edge of the electrode. The overshooting of the frequency response at low frequency can be eliminated by replacing the straight sidelines of the triangle by three-point polylines. We found that the concave pentagon electrode achieves a wide and flat frequency response up to about 
GHz for the J-PARC Main Ring.
Kishida, Keigo*; Kikuchi, Masahiro; Nakamura, Hideo*; Kobayashi, Yasuhiko; Ukai, Mitsuko*
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 90, 2015/03
Kishida, Keigo*; Kawamura, Shoei*; Kikuchi, Masahiro; Nakamura, Hideo*; Kobayashi, Yasuhiko; Ukai, Mitsuko*
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 86, 2014/03
Kishida, Keigo*; Kawamura, Shoei*; Kameya, Hiromi*; Nakamura, Hideo*; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Ukai, Mitsuko*
Radioisotopes, 63(3), p.131 - 137, 2014/03
Using Pulse-Electron Spin Resonance (Pulse-ESR) spectroscopy and Continuous Wave-Electron Spin Resonance (CW-ESR) spectroscopy, we revealed the relaxation time (T
, T
) of radicals induced in irradiated foods. The relaxation time was directly analyzed by Pulse-ESR. Using CW-ESR, the relaxation time was calculated by the measured spectrum parameter indirectly. We succeeded in the detection of Pulse-ESR signal of irradiated hard wheat flour and irradiated black pepper. It was suggested that using CW-ESR T and T can be calculated effectively, but the value was tend to slightly lower due to the parameters for calculation are affected by the contents of food especially protein.
Kishida, Keigo*; Kawamura, Shoei*; Nakamura, Hideo*; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Ukai, Mitsuko*
Shokuhin Shosha, 48(1), p.11 - 18, 2013/09
no abstracts in English
Kaimori, Yoshihiko; Sakamoto, Yuki*; Kawamura, Shoei*; Kishida, Keigo*; Kikuchi, Masahiro; Nakamura, Hideo*; Kobayashi, Yasuhiko; Ukai, Mitsuko*
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 79, 2013/01
no abstracts in English
Kishida, Keigo*; Kaimori, Yoshihiko*; Kawamura, Shoei*; Sakamoto, Yuki*; Nakamura, Hideo*; Kikuchi, Masahiro; Shimoyama, Yuhei; Kobayashi, Yasuhiko; Ukai, Mitsuko*
Shokuhin Shosha, 47(1), p.1 - 5, 2012/09
no abstracts in English
Kando, Masaki; Pirozhkov, A. S.; Nakamura, Tatsufumi; Hayashi, Yukio; Kotaki, Hideyuki; Kawase, Keigo*; Esirkepov, T. Z.; Fukuda, Yuji; Kiriyama, Hiromitsu; Okada, Hajime; et al.
AIP Conference Proceedings 1465, p.159 - 166, 2012/07
Times Cited Count：0 Percentile：0.13Hayashi, Yukio; Pirozhkov, A. S.; Kando, Masaki; Fukuda, Yuji; Faenov, A.*; Kawase, Keigo*; Pikuz, T.*; Nakamura, Tatsufumi; Kiriyama, Hiromitsu; Okada, Hajime; et al.
Optics Letters, 36(9), p.1614 - 1616, 2011/05
Times Cited Count：22 Percentile：72.19(Optics)The interaction between a 25 TW laser and Xe clusters at a peak intensity of 1
10
W/cm
has been investigated. Xe K-shell X-rays, whose energies are approximately 30 keV, were clearly observed with a hard X-ray charge-coupled device (X-ray CCD) at 3.4 MPa. Moreover, we studied the yield of the Xe K-shell X-rays by changing the pulse duration of the laser at a constant laser energy, and found that the pulse duration of 40 fs is better than that of 300 fs for generating Xe K-shell X-rays.
Fukuda, Yuji; Faenov, A.*; Tampo, Motonobu; Pikuz, T.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kameshima, Takashi*; et al.
Progress in Ultrafast Intense Laser Science VII, p.225 - 240, 2011/05
http://www.springer.com/physics/atomic,+molecular,+optical+%26+plasma+physics/book/978-3-642-18326-3We present substantial enhancement of the accelerated ion energies up to 10-20 MeV per nucleon by utilizing the unique properties of the cluster-gas target irradiated with 40-fs laser pulses of only 150 mJ energy, corresponding to approximately tenfold increase in the ion energies compared to previous experiments using thin foil targets. A particle-in-cell simulation infers that the high energy ions are generated at the rear side of the target due to the formation of a strong dipole vortex structure in sub-critical density plasmas. The demonstrated method can be important in the development of efficient laser ion accelerators for hadron therapy and other applications.
Faenov, A. Y.; Pikuz, T. A.*; Fukuda, Yuji; Kando, Masaki; Kotaki, Hideyuki; Homma, Takayuki; Kawase, Keigo; Kameshima, Takashi*; Pirozhkov, A. S.; Yogo, Akifumi; et al.
Applied Physics Letters, 95(10), p.101107_1 - 101107_3, 2009/09
Times Cited Count：30 Percentile：73.44(Physics, Applied)
O(
) reaction at forward angles and structure of the spin-dipole resonancesKawabata, Takahiro*; Ishikawa, Takatsugu*; Ito, M.*; Nakamura, M.*; Sakaguchi, Harutaka*; Takeda, H.*; Taki, T.*; Uchida, Makoto*; Yasuda, Yusuke*; Yosoi, Masaru*; et al.
Physical Review C, 65(6), p.064316_1 - 064316_12, 2002/06
Times Cited Count：19 Percentile：69.12(Physics, Nuclear)no abstracts in English
O (p,p') experimentKawabata, Takahiro*; Akimune, Hidetoshi*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Hara, Keigo*; Hatanaka, Kichiji*; Hosono, K.*; Ishikawa, Takatsugu*; et al.
Nuclear Instruments and Methods in Physics Research A, 459(1-2), p.171 - 176, 2001/02
Times Cited Count：17 Percentile：75.34(Instruments & Instrumentation)no abstracts in English
Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Yogo, Akifumi; Pikuz, T. A.*; Kando, Masaki; Kotaki, Hideyuki; Daito, Izuru; Hayashi, Yukio; Kawase, Keigo; et al.
no journal, ,
A near-critical plasma cloud embedded in an underdense plasma, created by the interaction of laser prepulses with the cluster-gas target, is irradiated by the high-repetition laser pulses. Through a shadowgraphy, observed is a 3-mm long stable channel formation, from which high energy ions, accelerated up to 10 MeV/n in the laser propagation direction, are detected in a stack of plastic nuclear track detectors.
Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kawase, Keigo; et al.
no journal, ,
We demonstrate generation of 10-20 MeV/u ions with a compact 4 TW laser using a gas target mixed with submicron clusters, corresponding to tenfold increase in the ion energies compared to previous experiments with solid targets. It is inferred that the high energy ions are generated due to formation of a strong dipole vortex structure. The demonstrated method has a potential to construct compact and high repetition rate ion sources for hadron therapy and other applications.
Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Homma, Takayuki; Kawase, Keigo; Yogo, Akifumi; et al.
no journal, ,
We demonstrate generation of 10-20 MeV/u ions with a compact 4 TW laser using a gas target mixed with submicron clusters, corresponding to tenfold increase in the ion energies compared to previous experiments with solid targets. It is inferred that the high energy ions are generated due to formation of a strong dipole vortex structure.
Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Homma, Takayuki; Kawase, Keigo; Kotaki, Hideyuki; et al.
no journal, ,
An approach for accelerating ions, with the use of a cluster-gas target and an ultrashort pulse laser of 150-mJ energy and 40-fs duration, is presented. Ions with energy 10-20 MeV per nucleon having a small divergence (full angle) of 3.4
are generated in the forward direction, corresponding to approximately tenfold increase in the ion energies compared to previous experiments using solid targets. It is inferred from a particle-in-cell simulation that the high energy ions are generated at the rear side of the target due to the formation of a strong dipole vortex structure in subcritical density plasmas.
Faenov, A. Y.; Pikuz, T. A.*; Fukuda, Yuji; Kando, Masaki; Kotaki, Hideyuki; Homma, Takayuki; Kawase, Keigo; Pirozhkov, A. S.; Yogo, Akifumi; Tampo, Motonobu; et al.
no journal, ,
Fukuda, Yuji; Faenov, A.*; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kawase, Keigo; et al.
no journal, ,
We present substantial enhancement of the accelerated ion energies up to 10-20 MeV per nucleon by utilizing the unique properties of the cluster-gas target irradiated with 40-fs laser pulses of only 150 mJ energy, corresponding to approximately tenfold increase in the ion energies compared to previous experiments using thin foil targets. A particle-in-cell simulation infers that the high energy ions are generated at the rear side of the target due to the formation of a strong dipole vortex structure in sub-critical density plasmas. The demonstrated method can be important in the development of efficient laser ion accelerators for hadron therapy and other applications.