HIAT2015 - List of Authors (Okamura, K.)

Paper	Title	Page
MOPA17	Super-Bunch Induction Acceleration Scheme in the KEK Digital Accelerator	80
	T. Yoshimoto, K. Takayama TIT, Yokohama, Japan T. Adachi, E. Kadokura, T. Kawakubo, X. Liu, K. Okamura, S. Takano, K. Takayama KEK, Ibaraki, Japan T. Adachi, K. Takayama Sokendai, Ibaraki, Japan H. Kobayashi Tokyo City University, Tokyo, Japan X. Liu Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
	One of our next missions for the KEK digital accelerator,* is to demonstrate super-bunch (very long beam) acceleration technique in which a beam length occupies over half of the ring at injection**. This machine uses an induction cell driven by a switching power supply (SPS) which can generate rectangular pulses with their timings precisely controlled by a field-programmable gate array (FPGA). A power supply for the SPS is planned to be upgraded from present DC setup to a time-varying type generating a beam-required acceleration voltage per turn. This suppresses an emittance blow-up longitudinally and allows the super-bunch acceleration stably. In this presentation, we discuss concrete super-bunch acceleration scheme with simulation results and its hardware developments. T. Iwashita et al, Phys. Rev. ST-AB 14, 071301 (2011). K. Takayama, T. Yoshimoto et al, Phys. Rev. ST-AB 17, 010101 (2014). * K. Takayama et al, Phys. Rev. Lett. 88, 144801 (2002).
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MOPA18	A Racetrack-Shape Fixed Field Induction Accelerator for Giant Cluster Ions	83
	K. Takayama, T. Adachi, K. Okamura, M. Wake KEK, Ibaraki, Japan Y. Iwata NIRS, Chiba-shi, Japan
	Funding: Grants-In-Aid for Scientific　Research　（B)（KAKENHI　No. 15H03589) A novel scheme for a racetrack-shape fixed field induction accelerator (RAFFIA) capable of accelerating extremely heavy cluster ions (giant cluster ions) * is described. The key feature of this scheme is rapid induction acceleration by localized induction cells. Triggering the induction voltages provided by the signals from the circulating bunch allows repeated acceleration of extremely heavy cluster ions. Under the hypothesis that the RAFFIA is an induction synchrotron ** with an adiabatically varying circumference, the given RAFFIA example is capable of realizing the integrated acceleration voltage of 50 MV per acceleration cycle for C-60 (A=720 and Q=7). Using 90° bending magnets with a reversed field strip and field gradient is crucial for assuring orbit stability in the RAFFIA. Interesting beam physics such as resonance crossing during an acceleration cycle is discussed, including the structural stability of the cluster ion itself in the bending fields. * K.Takayama, T.Adachi, M.Wake, and K.Okamura, Phys. Rev. ST-AB 18, 050101(2015). ** K.Takayama and R.J. Briggs, Chapter 11 and 12 in Induction Synchrotron (Springer, Heidelberg, 2011).
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Paper

Title

Page

Super-Bunch Induction Acceleration Scheme in the KEK Digital Accelerator

80

T. Yoshimoto, K. Takayama
TIT, Yokohama, Japan
T. Adachi, E. Kadokura, T. Kawakubo, X. Liu, K. Okamura, S. Takano, K. Takayama
KEK, Ibaraki, Japan
T. Adachi, K. Takayama
Sokendai, Ibaraki, Japan
H. Kobayashi
Tokyo City University, Tokyo, Japan
X. Liu
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan

One of our next missions for the KEK digital accelerator*,** is to demonstrate super-bunch (very long beam) acceleration technique in which a beam length occupies over half of the ring at injection***. This machine uses an induction cell driven by a switching power supply (SPS) which can generate rectangular pulses with their timings precisely controlled by a field-programmable gate array (FPGA). A power supply for the SPS is planned to be upgraded from present DC setup to a time-varying type generating a beam-required acceleration voltage per turn. This suppresses an emittance blow-up longitudinally and allows the super-bunch acceleration stably. In this presentation, we discuss concrete super-bunch acceleration scheme with simulation results and its hardware developments.
* T. Iwashita et al, Phys. Rev. ST-AB 14, 071301 (2011).
** K. Takayama, T. Yoshimoto et al, Phys. Rev. ST-AB 17, 010101 (2014).
*** K. Takayama et al, Phys. Rev. Lett. 88, 144801 (2002).

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MOPA18

A Racetrack-Shape Fixed Field Induction Accelerator for Giant Cluster Ions

83

K. Takayama, T. Adachi, K. Okamura, M. Wake
KEK, Ibaraki, Japan
Y. Iwata
NIRS, Chiba-shi, Japan

Funding: Grants-In-Aid for Scientific　Research　（B)（KAKENHI　No. 15H03589)
A novel scheme for a racetrack-shape fixed field induction accelerator (RAFFIA) capable of accelerating extremely heavy cluster ions (giant cluster ions) * is described. The key feature of this scheme is rapid induction acceleration by localized induction cells. Triggering the induction voltages provided by the signals from the circulating bunch allows repeated acceleration of extremely heavy cluster ions. Under the hypothesis that the RAFFIA is an induction synchrotron ** with an adiabatically varying circumference, the given RAFFIA example is capable of realizing the integrated acceleration voltage of 50 MV per acceleration cycle for C-60 (A=720 and Q=7). Using 90° bending magnets with a reversed field strip and field gradient is crucial for assuring orbit stability in the RAFFIA. Interesting beam physics such as resonance crossing during an acceleration cycle is discussed, including the structural stability of the cluster ion itself in the bending fields.
* K.Takayama, T.Adachi, M.Wake, and K.Okamura, Phys. Rev. ST-AB 18, 050101(2015).
** K.Takayama and R.J. Briggs, Chapter 11 and 12 in Induction Synchrotron (Springer, Heidelberg, 2011).

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)