Paper |
Title |
Page |
TUPPD035 |
SuperKEKB Injector Upgrade for High Charge and Low Emittance Electron Beam |
1482 |
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- M. Yoshida, N. Iida, Y. Ogawa, M. Sato, L. Zang
KEK, Ibaraki, Japan
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The design strategy of SuperKEKB is based on the nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, new photocathode RF-Gun with the focusing electric field was installed. Further the emittance growth in the linac is an important issue for the low emittance injection. We will report the machine study of the RF-Gun and the emittance growth through the linac.
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TUPPR005 |
Linac Upgrade in Intensity and Emittance for SuperKEKB |
1819 |
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- T. Higo, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, K. Furukawa, Y. Higashi, H. Honma, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
- D. Satoh
TIT, Tokyo, Japan
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The SuperKEKB is designed to produce 40 times luminosity than that of the KEKB. In order to realize such a high luminosity, the injector linac should provide both electron and positron beams of about 4-5 nC/bunch, which is several times higher than before. In addition, their emittance requirement of the injection beam to the rings is 20 microns, which is a factor of a few tens smaller than before. The intensity and emittance of the electron beam are realized directly by developing the photo RF gun. In contrast, the positron intensity is increased by adopting a higher capture efficiency system with flux concentrator followed by large-aperture accelerators, while its emittance is reduced by a damping ring. For preserving such a low emittance of both beams toward the injection to the rings, the suppression of the emittance growth is crucial. To this end, the alignment of the accelerator components should be a few tens of microns, where we need an improvement by more than a factor 10. The beam-based alignment is definitely needed with better-resolution BPMs. In the present paper are reviewed the overall progress and perspective of the design and the associated component developments.
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TUPPR051 |
Development of L-Band Positron Capture Accelerating Structure with Kanthal-coated Collinear Load for SuperKEKB |
1933 |
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- F. Miyahara, Y. Arakida, T. Higo, N. Iida, K. Kakihara, T. Kamitani, S. Matsumoto
KEK, Ibaraki, Japan
- L. Lilje
DESY, Hamburg, Germany
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In order to achieve a luminosity of 8x1035 cm-2 s-1, the SuperKEKB injector is required to provide both e+e− beams higher in intensity by a factor 4-5 than those for KEKB, and with a low emittance of about 20 um. A damping ring is used to fulfill this low emittance requirement for e+, but the intensity increase is realized by a larger yield from the conversion target to the damping ring. To this end, the L-band capture system is adopted to increase the transverse and longitudinal acceptance. The capture section consists of a Tungsten conversion target with flux concentrator followed by two L-band 2.4m-long accelerating structures and continuing to the large aperture S-band 2m-long ones. The L-band frequency of 1.3 GHz, 5/11 times S-band one, was adopted to suppress the satellite bunches in the S-band system. This L-band system is surrounded by a solenoid magnet producing 4kG on axis. To compose compact magnet system, the output coupler of the L-band accelerating structure is replaced by the Kanthal coated collinear load section. In this paper, we will discuss the design of the accelerating structure and present the studies of Kanthal layer coated on copper.
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TUPPR089 |
Design Study of Beam Injection for SuperKEKB Main Ring |
2035 |
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- T. Mori, N. Iida, M. Kikuchi, T. Mimashi, Y. Sakamoto, H. Sugimoto, S. Takasaki, M. Tawada
KEK, Ibaraki, Japan
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The SuperKEKB project is in progress toward the initial physics run in the year 2015. It assumes the nano-beam scheme, in which the emittance of the colliding beams is ε=4.6 nm. The emittance of the injected beam is ε=1.46 nm. To achieve such a low emittance, it is vitally important to preserve the emittance during the transport of the beam from the linac to the main ring. One of the most difficult parts is the injection system. We are considering the synchrotron injection for the electron-line to avoid a beam blowup in the ring after injection, which is caused by a beam-beam interaction with the stored beam. The optics study for electron injection and the current R&D status for the septum magnet will be reported in this paper.
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