HIAT2015 - List of Authors (Adachi, T.)

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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MOPA26	SI-Thyristor Matrix Array Driven Electrostatic Injection Kicker for the KEK Digital Accelerator and Beam Dynamics Analysis of Injection	101
	H. Kobayashi Tokyo City University, Tokyo, Japan T. Adachi, T. Kawakubo KEK, Ibaraki, Japan X. Liu TIT, Yokohama, Japan
	For heavy ion beam injection into the KEK-DA ring [], the electrostatic (ES) kicker is used []. A voltage of 20 kV is put across the electrostatic electrodes before injection so as to deflect the injected beam on the ring orbit. The ES-Kicker excitation circuit where a coaxial cable is charged to the required voltage by a resonant charging power supply and discharged just after beam injection. The SI-Thyristor Matrix Array (SI-Thy MA) as a discharging device has been developed to replace the conventional thyratron. The developed SI-Thy MA has proved to be quite useful in getting rid of inherent issues associated with thyratron's use. Recently it has turned out that ringing in a voltage pulse of 3.5 μs, which is originated from its longer switching time than that of the thyratron, affects on beam injection dynamics, resulting inμbunch formation. In order to understand this phenomenon, a computer simulation code including the longitudinal space-charge effects has been developed. Comparisons of the experimental results obtained for various parameters with the computer simulation will be discussed. [] T.Iwashita et al.,"KEK Digital Accelerator",Phys. Rev.ST-AB 14,071301(2011). [**] T.Adachi and T.Kawakubo,"Electrostatic Injection Kicker for KEK-DA",Phys. Rev.ST-AB 16, 053501 (2013).
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FRM1C03	A Compact Hadron Driver for Cancer Therapies with Continuous Energy Sweep Scanning	291
	K.W. Leo Malaysian Nuclear Agency, Kajang, Malaysia T. Adachi, T. Kawakubo, T. Monma, K. Takayama KEK, Ibaraki, Japan T. Adachi, K. Takayama Sokendai, Ibaraki, Japan T.S. Dixit SAMEER, Mumbai, India K. Takayama TIT, Yokohama, Japan
	A design of a compact hadron driver for future cancer therapies based on the induction synchrotron concept is given. In order to realize a slow extraction technique in a fast cycling synchrotron, which allows the energy sweep beam scanning, the zero momentum-dispersion D(s) region and high flat D(s) region are necessary. The lattice has the two fold symmetry with a circumference of 52.8 m, 2 m-long dispersion-free straight section, and 3 m-long large flat dispersion straight section. Assuming a 1.5 T bending magnet, the ring can deliver heavy ions of 200 MeV/au at 20 Hz. A beam fraction is dropped from the barrier bucket at the desired timing and the increasing negative momentum deviation of this beam fraction becomes enough large for the fraction to fall in the ES septum extraction gap, which is placed at the large D(s) region. The programmed energy sweeping extraction makes spot scanning beam irradiation on a cancer area in depth possible without an energy degrader avoiding the production of secondary particles or the degradation of emittance. Details of the lattice parameters and computer simulations for slow extraction are discussed.
	Slides FRM1C03 [5.557 MB]
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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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MOPA26

SI-Thyristor Matrix Array Driven Electrostatic Injection Kicker for the KEK Digital Accelerator and Beam Dynamics Analysis of Injection

101

H. Kobayashi
Tokyo City University, Tokyo, Japan
T. Adachi, T. Kawakubo
KEK, Ibaraki, Japan
X. Liu
TIT, Yokohama, Japan

For heavy ion beam injection into the KEK-DA ring [*], the electrostatic (ES) kicker is used [**]. A voltage of 20 kV is put across the electrostatic electrodes before injection so as to deflect the injected beam on the ring orbit. The ES-Kicker excitation circuit where a coaxial cable is charged to the required voltage by a resonant charging power supply and discharged just after beam injection. The SI-Thyristor Matrix Array (SI-Thy MA) as a discharging device has been developed to replace the conventional thyratron. The developed SI-Thy MA has proved to be quite useful in getting rid of inherent issues associated with thyratron's use. Recently it has turned out that ringing in a voltage pulse of 3.5 μs, which is originated from its longer switching time than that of the thyratron, affects on beam injection dynamics, resulting inμbunch formation. In order to understand this phenomenon, a computer simulation code including the longitudinal space-charge effects has been developed. Comparisons of the experimental results obtained for various parameters with the computer simulation will be discussed.
[*] T.Iwashita et al.,"KEK Digital Accelerator",Phys. Rev.ST-AB 14,071301(2011).
[**] T.Adachi and T.Kawakubo,"Electrostatic Injection Kicker for KEK-DA",Phys. Rev.ST-AB 16, 053501 (2013).

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FRM1C03

A Compact Hadron Driver for Cancer Therapies with Continuous Energy Sweep Scanning

291

K.W. Leo
Malaysian Nuclear Agency, Kajang, Malaysia
T. Adachi, T. Kawakubo, T. Monma, K. Takayama
KEK, Ibaraki, Japan
T. Adachi, K. Takayama
Sokendai, Ibaraki, Japan
T.S. Dixit
SAMEER, Mumbai, India
K. Takayama
TIT, Yokohama, Japan

A design of a compact hadron driver for future cancer therapies based on the induction synchrotron concept is given. In order to realize a slow extraction technique in a fast cycling synchrotron, which allows the energy sweep beam scanning, the zero momentum-dispersion D(s) region and high flat D(s) region are necessary. The lattice has the two fold symmetry with a circumference of 52.8 m, 2 m-long dispersion-free straight section, and 3 m-long large flat dispersion straight section. Assuming a 1.5 T bending magnet, the ring can deliver heavy ions of 200 MeV/au at 20 Hz. A beam fraction is dropped from the barrier bucket at the desired timing and the increasing negative momentum deviation of this beam fraction becomes enough large for the fraction to fall in the ES septum extraction gap, which is placed at the large D(s) region. The programmed energy sweeping extraction makes spot scanning beam irradiation on a cancer area in depth possible without an energy degrader avoiding the production of secondary particles or the degradation of emittance. Details of the lattice parameters and computer simulations for slow extraction are discussed.

Slides FRM1C03 [5.557 MB]

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