H. Takaki, Norio Nakamura, Yukinori Kobayashi, Kentaro Harada, Tsukasa Miyajima, Akira Ueda, Shinya Nagahashi, Miho Shimada, T. Obina, Tohru Honda,
We have developed a new beam injection system with a single pulsed sextupole magnet (PSM) at the photon factory storage ring (PF ring) in the High Energy Accelerator Research Organization. We demonstrated beam injection with this system and succeeded in storing a beam current of 450 mA, which is the normal operating beam current of the PF ring. Top-up injection was also achieved. Coherent dipole oscillation of the stored beam and fluctuation of photon intensity observed at synchrotron radiation beam ...
Tópico(s): Gyrotron and Vacuum Electronics Research
2010 - American Physical Society | Physical Review Special Topics - Accelerators and Beams
Ali Nsair, Katja Schenke‐Layland, Ben Van Handel, Denis Evseenko, Michaël Kahn, Peng Zhao, Joseph Mendelis, Sanaz Heydarkhan, Obina Awaji, Miriam Vottler, Susanne Geist, Jennifer Chyu, Nuria Gago‐López, Gay M. Crooks, Kathrin Plath, Joshua I. Goldhaber, Hanna Mikkola, W. Robb MacLellan,
Background Cardiovascular progenitor cells (CPCs) have been identified within the developing mouse heart and differentiating pluripotent stem cells by intracellular transcription factors Nkx2.5 and Islet 1 (Isl1). Study of endogenous and induced pluripotent stem cell (iPSC)-derived CPCs has been limited due to the lack of specific cell surface markers to isolate them and conditions for their in vitro expansion that maintain their multipotency. Methodology/Principal Findings We sought to identify specific ...
Tópico(s): Congenital heart defects research
2012 - Public Library of Science | PLoS ONE
M. Akemoto, Dai Arakawa, Atsushi Enomoto, Satoshi Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, Tohru Honda, Hiroaki Honma, N. Iida, Masahiko Ikeda, K. Kakihara, T. Kamitani, T. Kasuga, H. Katagiri, S. Kazakov, M. Kikuchi, Yukinori Kobayashi, H. Koiso, Norio Kudo, Miho Kurashina, Hideki Matsushita, T. Matsumoto, Shuji Matsumoto, S. Michizono, T. Mimashi, T. Mitsuhashi, Takako Miura, Tsukasa Miyajima, Shinya Nagahashi, H. Nakajima, K. Nakao, T. Obina, Y. Ogawa, Y. Ohnishi, A. Ohsawa, K. Oide, T. Oogoe, Masanori Satoh, T. Shidara, A. Shirakawa, M. Suetake, T. Sugimura, T. Suwada, M. Tadano, T. Takenaka, M. Tawada, Akira Ueda, Y. Yano, K. Yokoyama, M. Yoshida,
The KEKB injector linac has been continuously improved to enhance the stability of many devices and the efficiency of beam operation. These improvements include the development of the new C-band accelerating structure, pulse compressor, klystron, rf window, compact modulator, and the new positron production target using crystalline tungsten. We have also achieved two-bunch beam acceleration, the development of an energy spread monitor, a safety system upgrade, and an event-based timing and control ...
Tópico(s): Gyrotron and Vacuum Electronics Research
2013 - University of Oxford | Progress of Theoretical and Experimental Physics
Kenta Amemiya, Masako Sakamaki, T. Koide, K. Ito, K. Tsuchiya, Kentaro Harada, Tomohiro Aoto, Tatsuro Shioya, T. Obina, Shigeru Yamamoto, Yukinori Kobayashi,
Recent development in fast polarization switching at the soft X-ray beamline, BL-16A in the Photon Factory is reported. Two APPLE-II type undulators installed in a tandem configuration enables us to achieve polarization switching between not only two opposite circular polarizations, but also the vertical and horizontal linear polarizations. An energy shift is observed during polarization switching due to a vertical modulation in the electron beam, which has been reduced by properly correcting the ...
Tópico(s): Crystallography and Radiation Phenomena
2013 - IOP Publishing | Journal of Physics Conference Series
K. Tsuchiya, Tatsuro Shioya, Tomohiro Aoto, Kentaro Harada, T. Obina, Masako Sakamaki, Kenta Amemiya,
We have been developing a fast polarization-switching source for the vacuum ultraviolet and soft X-ray region at the B15-16 straight section of the 2.5-GeV Photon Factory (PF) storage ring. The source consists of two tandem APPLE-II-type elliptically polarizing undulators (EPUs), namely, U#16-1 and U#16-2, and a fast kicker system. The target frequency of polarization switching is 10 Hz. As the first step, we installed U#16-1 and five identical bump kickers in the PF ring in March 2008. Then, we constructed ...
Tópico(s): Adrenal and Paraganglionic Tumors
2013 - IOP Publishing | Journal of Physics Conference Series
M. Akemoto, Dai Arakawa, Seiji Asaoka, Enrico Cenni, Masato Egi, Kazuhiro Enami, K. Endo, Shigeki Fukuda, T. Furuya, K. Haga, Ryoichi Hajima, Kazufumi Hara, Kentaro Harada, Tohru Honda, Y. Honda, T. Honma, K. Hosoyama, E. Kako, Hiroaki Katagiri, Hiroshi Kawata, Yukinori Kobayashi, Yuuji Kojima, Yoshinari Kondou, Olga Tanaka, Tatsuya Kume, M. Kuriki, Hiroshi Matsumura, Hideki Matsushita, Shinichiro Michizono, Takako Miura, Tsukasa Miyajima, Shinya Nagahashi, Ryoji Nagai, H. Nakai, Hiromitsu Nakajima, Norio Nakamura, Kota Nakanishi, Kazuyuki Nigorikawa, N. Nishimori, Takashi Nogami, S. Noguchi, T. Obina, Feng Qiu, Hidenori Sagehashi, Hiroshi Sakai, S. Sakanaka, Shin‐ichi Sasaki, K. Satoh, M. Sawamura, Miho Shimada, Kenji Shinoe, T. Shishido, M. Tadano, Takeshi Takahashi, Ryota Takai, T. Takenaka, Yasunori Tanimoto, Takashi Uchiyama, Akira Ueda, Kensei Umemori, Ken Watanabe, Masahiro Yamamoto,
Energy-recovery linacs (ERLs) are promising for advanced synchrotron light sources, high-power free electron lasers (FELs), high-brightness gamma-ray sources, and electron–ion colliders. To demonstrate the critical technology of ERL-based light sources, we have designed and constructed a test accelerator, the compact ERL (cERL). Using advanced technology that includes a photocathode direct current (DC) electron gun and two types of 1.3-GHz-frequency superconducting cavities, the cERL was designed to ...
Tópico(s): Gyrotron and Vacuum Electronics Research
2017 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
S. Benson, M. Borland, D. Douglas, D.H. Dowell, C. Hernandez-Garcia, D. Kayran, G. Krafft, R. Legg, E.R. Moog, T. Obina, Robert Rimmer, V. Yakimenko,
In this paper we review the current state of research on energy recovered linacs as drivers for future X-ray sources. For many types of user experiments, such sources may have substantial advantages compared to the workhorse sources of the present: high energy storage rings. Energy recovered linacs need to be improved beyond present experience in both energy and average current to support this application. To build an energy recovered linac based X-ray user facility presents many interesting challenges. ...
Tópico(s): X-ray Spectroscopy and Fluorescence Analysis
2010 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
Masahiro Katoh, Y. Hori, Yukinori Kobayashi, S. Sakanaka, M. Izawa, K. Haga, Tohru Honda, T. Mitsuhashi, T. Obina, C. O. Pak, K. Ohmi, K. Tsuchiya, Noriichi Kanaya, Akira Ueda, M. Tadano, Yoichi Takiyama, Seiji Asaoka, Takashi Nogami, Tatsuro Shioya, A. Mishina, Yoichi Sato, S. Tokumoto, Takeshi Takahashi, T. Kasuga, H. Maezawa, Masanori Kobayashi, H. Kobayakawa,
Reconstruction of the Photon Factory storage ring (PF ring; 2.5 GeV) is now in progress to provide very brilliant synchrotron radiation to users, i.e. the emittance is being reduced by a factor of five. Components, such as the quadrupole and sextupole magnets, vacuum chambers, beamlines and beam-position monitors, are being replaced by new ones in 16 normal-cell sections of the PF ring. The accelerating cavities, injection systems and control systems are also being replaced. Operation will commence ...
Tópico(s): Superconducting Materials and Applications
1998 - Wiley | Journal of Synchrotron Radiation
Norio Nakamura, R. Kato, Hiroshi Sakai, K. Tsuchiya, Yasunori Tanimoto, Y. Honda, Tsukasa Miyajima, Miho Shimada, Takanori Tanikawa, Olga Tanaka, T. Obina, Hiroshi Kawata,
Abstract The development of a high-power EUV light source is very important in EUV lithography to overcome the stochastic effects for higher throughput and higher numerical aperture (NA) in the future. We have designed and studied a high-power EUV free-electron laser (FEL) based on energy-recovery linac (ERL) for future lithography. We show that the EUV-FEL light source has many advantages, such as extremely high EUV power without tin debris, upgradability to a Beyond EUV (BEUV) FEL, polarization controllability ...
Tópico(s): Particle accelerators and beam dynamics
2023 - Institute of Physics | Japanese Journal of Applied Physics
T. Obina, T. Kasuga, M. Tobiyama, Tomoo Katsura, Koji Tamura,
A photon counting system for measuring the time structure of bunches, such as the single-bunch impurity and the longitudinal distribution of electrons, was installed and has been improving in the KEK PF positron storage ring. Agreement between the experimental results concerning the rate of impurity growth and a calculation taking account of the relativistic effects of electron-electron scattering, which is the origin of the impurity growth, was fairly good. A deformation of the distribution at ...
Tópico(s): Particle Accelerators and Free-Electron Lasers
1995 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
Tohru Honda, Seiji Asaoka, W. Cheng, K. Haga, Kentaro Harada, Y. Hori, M. Izawa, T. Kasuga, Yukinori Kobayashi, H. Maezawa, A. Mishina, T. Mitsuhashi, Tsukasa Miyajima, Hiroshi Miyauchi, Shinya Nagahashi, Takashi Nogami, T. Obina, C. O. Pak, S. Sakanaka, Hiroyuki Sasaki, Yasuo Satô, Tatsuro Shioya, M. Tadano, Takeshi Takahashi, Yasunori Tanimoto, K. Tsuchiya, Takashi Uchiyama, Akira Ueda, Kensei Umemori, Shigeru Yamamoto,
At the 2.5‐GeV ring of the Photon Factory, a large reconstruction of the lattice around the straight sections has been accomplished in 2005. Thus reconstruction is the main part of the straight‐sections upgrade project to rebuild existing undulators and to increase the number of undulator beamlines. As a result of the reconstruction, four short straight sections have been newly created and the lengths of the existing straight sections have been much extended. To exploit the new straight sections, ...
Tópico(s): Advanced X-ray Imaging Techniques
2007 - American Institute of Physics | AIP conference proceedings
It has been reported that the beam lifetime in electron storage rings can be improved by applying a small phase modulation on the rf accelerating voltage at a frequency of two-times the synchrotron oscillation frequency. This effect can be explained as being due to the improved Touschek lifetime that is caused by an excited bunch-shape oscillation in the stored bunches. In order to understand this phenomenon further, we investigated the induced bunch-shape oscillation in the 2.5-GeV Photon Factory ...
Tópico(s): Advanced X-ray Imaging Techniques
2001 - Institute of Physics | Japanese Journal of Applied Physics
Y. Honda, Miho Shimada, Tsukasa Miyajima, Takahiro Hotei, Norio Nakamura, R. Kato, T. Obina, Ryota Takai, Kentaro Harada, Akira Ueda,
Realization of a short bunch beam by manipulating the longitudinal phase space distribution with a finite longitudinal dispersion following an off-crest acceleration is a widely used technique. The technique was applied in a compact test accelerator of an energy-recovery linac scheme for compressing the bunch length at the return loop. A diagnostic system utilizing coherent transition radiation was developed for the beam tuning and for estimating the bunch length. By scanning the beam parameters, ...
Tópico(s): Gyrotron and Vacuum Electronics Research
2017 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
Y. Honda, Miho Shimada, Alexander Aryshev, R. Kato, Tsukasa Miyajima, T. Obina, Ryota Takai, Takashi Uchiyama, Naoto Yamamoto,
With a low emittance and short-bunch electron beam at a high repetition rate realized by a superconducting linac, stimulated excitation of an optical cavity at the terahertz spectrum range is shown. The electron beam passes through small holes in the cavity mirrors without being destroyed. A sharp resonance structure which indicates wideband stimulated emission via coherent diffraction radiation is observed while scanning the round-trip length of the cavity.
Tópico(s): Gyrotron and Vacuum Electronics Research
2018 - American Physical Society | Physical Review Letters
Y. Honda, Masahiro Adachi, Shu Eguchi, Masafumi Fukuda, Nao Higashi, R. Kato, Takako Miura, Tsukasa Miyajima, Shinya Nagahashi, Norio Nakamura, Kazuyuki Nigorikawa, Takashi Nogami, T. Obina, Hidenori Sagehashi, Hiroshi Sakai, Miho Shimada, Tatsuro Shioya, Ryota Takai, Olga Tanaka, Yasunori Tanimoto, K. Tsuchiya, Takashi Uchiyama, Akira Ueda, Masahiro Yamamoto, Demin Zhou, Masayuki Kakehata, Tadatake Sato, Hidehiko Yashiro, Ryoichi Hajima,
The mid-infrared range is an important spectrum range where materials exhibit a characteristic response corresponding to their molecular structure. A free-electron laser (FEL) is a promising candidate for a high-power light source with wavelength tunability to investigate the nonlinear response of materials. Although the self-amplification spontaneous emission (SASE) scheme is not usually adopted in the mid-infrared wavelength range, it may have advantages such as layout simplicity, the possibility ...
Tópico(s): Advanced X-ray Imaging Techniques
2021 - American Institute of Physics | Review of Scientific Instruments
Feng Qiu, Takako Miura, Dai Arakawa, Nao Higashi, E. Kako, T. Matsumoto, Shinichiro Michizono, Tsukasa Miyajima, T. Obina, Hiroshi Sakai, Kensei Umemori,
At the KEK compact energy recovery linac (cERL), a new beam line to produce radioisotopes (RIs) was constructed. To increase the beam energy for RI production, we proposed to switch the operation mode from continuous-wave mode to pulse mode. The first commissioning test of the cERL superconducting radio frequency (RF) cavities operated in pulse mode was therefore carried out. The RF pulse pattern for each cavity was carefully selected according to the corresponding cavity’s loaded Q and the capabilities ...
Tópico(s): Superconducting Materials and Applications
2020 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
Ji-Gwang Hwang, Eun-San Kim, Tsukasa Miyajima, Y. Honda, Kentaro Harada, Miho Shimada, Ryota Takai, Tatsuya Kume, Shinya Nagahashi, T. Obina, Norio Nakamura, S. Sakanaka, Ryoichi Hajima, Ryoji Nagai, N. Nishimori, Masahiro Yamamoto, Takashi Uchiyama, E. Kako, Shinichiro Michizono, Takako Miura,
Abstract For a future synchrotron light source based on a linac, e.g. an X-ray free electron laser and an energy recovery linac (ERL), an injector is a key component to generate a high brightness electron beam. For the acceleration and transportation of the electron beam in the injector, the adjustment of beam orbit inside the cavity is important to avoid the deterioration of the beam quality due to the transverse electric field of it, which causes the transverse emittance growth. To adjust the beam ...
Tópico(s): Advanced X-ray Imaging Techniques
2014 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
Brian E. O’Rourke, Takeshi Fujiwara, K. Furukawa, M. Furusaka, Noriyosu Hayashizaki, H. Kato, K. Kino, R. Kuroda, Koji Michishio, Takemi Muroga, Kazuyuki Nigorikawa, T. Obina, Hiroshi Ogawa, Nagayasu Oshima, Daisuke Satoh, N. Sei, Tamao Shishido, Ryoichi Suzuki, Masahito Tanaka, Yo Tomota, H. Toyokawa, Akira Watazu,
A new electron accelerator has been designed and is now under construction at AIST, Tsukuba, Japan. The accelerator will be used to produce a pulsed neutron beam for materials analysis. The design maximizes the yield of slow neutrons with high pulse temporal resolution as described in a previous publication [K. Kino et al., Nuclear Inst. and Methods in Physics Research, A 927 (2019) 407–418]. The accelerator is composed of a thermal cathode type electron gun with S-Band buncher/accelerator cavity ...
Tópico(s): Particle Detector Development and Performance
2019 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms
Feng Qiu, Takako Miura, Dai Arakawa, Nao Higashi, Y. Honda, E. Kako, T. Matsumoto, Shinichiro Michizono, Tsukasa Miyajima, T. Obina, Hiroshi Sakai, Kensei Umemori, Masahiro Yamamoto,
A disturbance observer (DOB)-based control approach was verified using the low-level radio-frequency systems of superconducting (SC) cavities operated in a continuous wave (CW) mode in a compact energy recovery linac (cERL) at KEK. This approach compensates for both predictable and unpredictable disturbances in a radio frequency (rf) system such as beam loading, Lorentz force detuning, and microphonics. This paper generalizes the DOB method in pulsed SC rf systems in the cERL at KEK. The results show ...
Tópico(s): Superconducting Materials and Applications
2021 - American Physical Society | Physical Review Accelerators and Beams
Ali Nsair, Katja Schenke‐Layland, Ben Van Handel, Denis Evseenko, Michaël Kahn, Peng Zhao, Joseph Mendelis, Sanaz Heydarkhan, Obina Awaji, Miriam Vottler, Susanne Geist, Jennifer Chyu, Nuria Gago‐López, Gay M. Crooks, Kathrin Plath, Joshua I. Goldhaber, Hanna Mikkola, W. Robb MacLellan,
Background: Cardiovascular progenitor cells (CPCs) have been identified within the developing mouse heart and differentiating pluripotent stem cells by intracellular transcription factors Nkx2.5 and Islet 1 (Isl1).Study of endogenous and induced pluripotent stem cell (iPSC)-derived CPCs has been limited due to the lack of specific cell surface markers to isolate them and conditions for their in vitro expansion that maintain their multipotency.Methodology/Principal Findings: We sought to identify specific ...
Tópico(s): Tissue Engineering and Regenerative Medicine
2012 - Public Library of Science | PLoS ONE
... Miyajima, H. Miyauchi, S. Nagahashi, T. Nogami, T. Obina, C. O. Pak, S. Sakanaka, Y. Sato, T. ...
Tópico(s): Advanced X-ray and CT Imaging
2004 - American Institute of Physics | AIP conference proceedings
Trio Yuda Septiawan, Sri Sumardiasih, Wilfrida M. Obina, Agus Supriyanto, Khairuddin Khairuddin, C. Cari,
Zinc Oxide (ZnO) is a semiconductor material that is used in addition to Titanium Dioxide (TiO2) used in the manufacture of Dye-Sensitized Solar Cell (DSSC). ZnO synthesized by using sol-gel mixture of zinc nitrate tetrahydrate (Zn (NO3)2.4H2O), ammonium hydroxide (NH4OH) and polyethylene glycol (PEG). In this study, the dye was extracted from the leaves of grass jelly (Cyclea barbata). Nanocomposite ZnO/TiO2 (mixture between ZnO and TiO2) was obtained by adding the results of the synthesis of ZnO and TiO2. ...
Tópico(s): Copper-based nanomaterials and applications
2017 - American Institute of Physics | AIP conference proceedings
Agus Supriyanto, Wilfrida M. Obina, Trio Yuda Septiawan, Ari Handono Ramelan, Fahru Nurosyid,
Dye-Sensitized Solar Cell (DSSC) is a generation of solar cells that utilize dye as a sensitizer and can convert solar energy into electrical energy. Components of DSSC are photoelectrode, dye, counter electrode and electrolyte. The photoelectrode is one of the devices of the DSSC. The modification of the photoelectrode is the insertion of copper on TiO2 to improve the performance of the DSSC. The method used in this research is the nanocomposite method and the electroplating method. Nanocomposites ...
Tópico(s): Advanced Photocatalysis Techniques
2019 - IOP Publishing | Journal of Physics Conference Series
A new control system for the Photon Factory (PF) electron storage ring has been developed, incorporating modern technologies in both high-level and low-level control layers. The Experimental Physics and Industrial Control System (EPICS) software toolkit was introduced as a major framework in the middle- and high-level control layers. In the low-level layer, Programmable Logic Controllers (PLC) was used for a safety control system, for RF klystron control boards and for the vacuum control system, etc. ...
Tópico(s): Advancements in Photolithography Techniques
2007 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
Tohru Honda, Seiji Asaoka, K. Haga, Kentaro Harada, Y. Honda, M. Izawa, Y. Kamiya, Yukinori Kobayashi, Tsukasa Miyajima, Hiroshi Miyauchi, Shinya Nagahashi, Norio Nakamura, Takashi Nogami, T. Obina, T. Ozaki, Hidenori Sagehashi, Hiroshi Sakai, S. Sakanaka, Hiroyuki Sasaki, Yoshihiro Sato, Miho Shimada, Kenji Shinoe, Tatsuro Shioya, M. Tadano, Toshihiro Tahara, Takeshi Takahashi, Ryota Takai, H. Takaki, Yasunori Tanimoto, K. Tsuchiya, Takashi Uchiyama, Akira Ueda, Kensei Umemori, Masanobu Yamamoto,
In 2011, two SR sources of KEK, PF-ring and PF-AR, needed to change the operation schedule because of the unprecedented earthquake on March 11. Though the injector linac and the storage rings suffered a serious damage, temporary recovery was accomplished quickly and the trial operation started in May. The regular user operation could be resumed in October 2011. In the restoration work after the earthquake, some old vacuum components were removed from PF-ring. This work fortunately brought an effect ...
Tópico(s): Particle accelerators and beam dynamics
2013 - IOP Publishing | Journal of Physics Conference Series
M. Tobiyama, E. Kikutani, T. Obina, Y. Minagawa, T. Kasuga,
Initial beam test of the KEKB bunch-by-bunch feedback system prototypes has been performed in the TRISTAN-AR on the longitudinal plane. A simple two-tap finite impulse response (FIR) filter system consisting of hardware logic realizes the function of the phase shift by 90°, the suppression of static components, and the delay of up to a hundred turns. With the prototype filter board and a longitudinal kicker, the feedback loop has been closed successfully. The shunt impedance of the kicker was estimated ...
Tópico(s): Gyrotron and Vacuum Electronics Research
1997 - American Institute of Physics | AIP conference proceedings
Kentaro Harada, T. Obina, Yukinori Kobayashi, Norio Nakamura, H. Takaki, Hiroshi Sakai,
An eigenvector method with constraints (EVC) is proposed as a new orbit correction scheme for synchrotron light sources. EVC efficiently corrects the global orbit in a storage ring, and can simultaneously perform exact correction of local orbits without deterioration of the global orbit. To demonstrate the advantages of EVC over the ordinary eigenvector method (EV), we carried out experimental studies at the Photon Factory storage ring (PF-ring) and the Photon Factory Advanced Ring (PF-AR) at the High ...
Tópico(s): Particle accelerators and beam dynamics
2009 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
S. Sakanaka, Yukinori Kobayashi, T. Mitsuhashi, T. Obina,
In order to investigate the possibility of exciting transverse higher-mode bunch oscillations for electron beams, we carried out a trial experiment in the Photon Factory (PF) storage ring at the High Energy Accelerator Research Organization (KEK). While storing a single bunch of electrons, we modulated the betatron tune at a frequency of two-times the fractional betatron frequency, using a high-frequency quadrupole magnet. The bunch oscillations excited were measured by detecting visible synchrotron ...
Tópico(s): Gyrotron and Vacuum Electronics Research
2003 - Institute of Physics | Japanese Journal of Applied Physics
S. Sakanaka, T. Mitsuhashi, T. Obina,
The frequencies (tunes) of transverse quadrupolar oscillations were measured in the 2.5-GeV Photon Factory storage ring at the High Energy Accelerator Research Organization (KEK). As a result, remarkable shifts in the quadrupolar frequencies with the bunch current were found; they were both positive and negative in the horizontal and vertical directions, respectively. This result can be explained by a focusing effect due to short-range wakefields containing a quadrupolar component.
Tópico(s): Gyrotron and Vacuum Electronics Research
2005 - American Physical Society | Physical Review Special Topics - Accelerators and Beams
Olga Tanaka, Norio Nakamura, Miho Shimada, Tsukasa Miyajima, Akira Ueda, T. Obina, Ryota Takai,
The beam halo mitigation is a very important challenge for reliable and safe operation of a high-energy machine. A systematic beam halo study was conducted at the KEK compact energy recovery linac (cERL) since non-negligible beam loss was observed in the recirculation loop during a common operation. We found that the beam loss can be avoided by making use of the collimation system. Beam halo measurements have demonstrated the presence of vertical beam halos at multiple locations in the beam line ( ...
Tópico(s): Particle Accelerators and Free-Electron Lasers
2018 - American Physical Society | Physical Review Accelerators and Beams