Triangle and concave pentagon electrodes for an improved broadband frequency response of stripline beam position monitors

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

https://doi.org/10.1103/PhysRevAccelBeams.19.021003

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.

Solid-liquid extraction of Mo and W by Aliquat 336 from HCl solutions toward extraction chromatography experiments of Sg

Komori, Yukiko*; Yokokita, Takuya*; Kasamatsu, Yoshitaka*; Haba, Hiromitsu*; Toyoshima, Atsushi; Toyomura, Keigo*; Nakamura, Kohei*; Kanaya, Jumpei*; Huang, M.*; Kudo, Yuki*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1385 - 1388, 2015/02

https://doi.org/10.1007/s10967-014-3476-4

We studied solid-liquid extraction behavior of carrier-free Mo and W radiotracers onto an Aliquat 336-loaded resin from HCl solutions toward extraction chromatography experiments of element 106, seaborgium(Sg). Distribution coefficients () of Mo and W on the resin were determined as a function of HCl concentration by a batch method. On-line extraction chromatography of Mo and W was also carried out in 2-8 M HCl solutions with an automated rapid chemistry apparatus. The order of extraction probability from 2 to 8 M HCl was MoW, which reflected the order of the values in the batch experiment.

Studies on the relaxation time of radicals in irradiated foods using pulse-ESR and CW-ESR

Kishida, Keigo*; Kawamura, Shoei*; Kameya, Hiromi*; Nakamura, Hideo*; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Ukai, Mitsuko*

Radioisotopes, 63(3), p.131 - 137, 2014/03

https://doi.org/10.3769/radioisotopes.63.131

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.

ESR studies on decay of radicals induced in irradiated foods

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

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2012-046.pdf

no abstracts in English

X-ray emission from relativistically moving electron density cusps

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

https://doi.org/10.1063/1.4737556

Ion acceleration in subcritical density plasma via interaction of intense laser pulse with cluster-gas target

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/978-3-642-18326-3

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.

Polarization transfer in the O() reaction at forward angles and structure of the spin-dipole resonances

Kawabata, 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

https://doi.org/10.1103/PhysRevC.65.064316

no abstracts in English

Ion acceleration in the interaction of short pulse laser radiation with the cluster-gas targets

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.

Energy increase in laser-driven multi-MeV ion generation using a cluster-gas target

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.

Submicron soft X-ray and multicharged ions imaging of nanostructures by using a femtosecond laser driven cluster based source

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, ,