| Paper | Title | Page |
|---|---|---|
| MOPA16 | Coherent Synchro-Beta Coupling in the KEK Digital Accelerator | 77 |
|
||
|
The required acceleration voltage per turn in any circular accelerator is written by Vacc=ρC0dB/dt, where ρ, C0, and B are the bending radius, circumference of the orbit, and magnetic flux density, respectively. Since the guiding magnetic fields of the KEK Digital Accelerator, which is a fast cycling induction synchrotron, are excited sinusoidally, an ideal profile of Vacc is of half sine. From the engineering constraint of the current induction acceleration system, however, the output voltage is always constant between 1.5 kV and 2.0 kV. Thus the induction acceleration voltage pulse is discretely generated based on the specific pulse density program so as to satisfy a size of the required voltage integrated for a short time period. The induction acceleration cells are placed at the region where the magnitude of the momentum dispersion function is not zero but 1.4 m. It has been reported that the coherent motion of the beam centroid is strongly excited at the early stage of acceleration cycle *. Discrete acceleration at the finite momentum dispersion function region is suspected to cause such a coherent motion.
* K.Takayama et al., "Induction acceleration of heavy ions in the KEK digital accelerator: Demonstration of a fast-cycling induction synchrotron", Phys. Rev. ST-AB 17, 010101(2014) |
||
| Export • | reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml) | |
| FRM1C03 | A Compact Hadron Driver for Cancer Therapies with Continuous Energy Sweep Scanning | 291 |
|
||
| 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] | |
| Export • | reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml) | |