IPAC2014 - List of Authors (Iida, N.)

Paper	Title	Page
MOPRO001	Upgrade Status of Injector LINAC for SuperKEKB	59
	T. Miura, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The SuperKEKB collider is under construction to achieve 40-times higher luminosity than that of previous KEKB collider. The injector LINAC should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron for SuperKEKB based on a nano-beam scheme. A photocathode RF-gun for low emittance electron beam has been already installed and the commissioning has started. The construction of positron capture section using a flux-concentrator and the dumping ring for low emittance positron beam is in progress. The simultaneous top-up injections to four storage-rings including photon factories is also required. In the upstream of dumping ring, the compatible optics between positron and electron has been designed. In the downstream of dumping ring, RF phase, focusing, and steering magnets will be switched by pulse to pulse against each beam-mode for optimising beam-transportation. This paper describes recent upgrade status toward the SuperKEKB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO001
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MOPRO023	SuperKEKB Beam abort System	116
	T. Mimashi, N. Iida, M. Kikuchi, T. Mori KEK, Ibaraki, Japan K. Abe Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan A. Sasagawa KYOCERA Corporation, Higashiomi-city, Shiga, Japan A. Tokuchi Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan
	The abort system of the SuperKEKB is described. The beam abort system consists of the beam abort kicker magnets, pulsed quadrupole magnets, a lambertson septum magnet and extracted window. The dumped beam is extracted with beam abort kicker through the extraction window. The pulsed quadrupole magnets make the beam spot size large at the window. The damages of the extraction window is tested with KEKB beam. The pulsed kicker power supply is under development.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO023
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MOPRO024	The Beam Test for the Ti Extraction Window Damage	119
	T. Mimashi, N. Iida, M. Kikuchi KEK, Ibaraki, Japan
	For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO024
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MOPRO025	Electron Beam Injection System for SuperKEKB Main Ring	122
	T. Mori, N. Iida, M. Kikuchi, T. Mimashi, Y. Sakamoto, S. Takasaki, M. Tawada KEK, Ibaraki, Japan
	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\mbox{nm}. The emittance of the injected beam is ε=1.46\mbox{nm}. To acheave 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 sections is the injection system. It has been pointed out that the injected beam has possibility of leading to blowup in the ring, which is caused by a beam-beam interaction with the stored positron beam. To avoid the beam blowup, the synchrotron injection is adopted as a backup option. The orbit of the electron injection beam has been designed and the septum magnet prototype has been constructed. The optics study for electron injection and the current R&D status for the septum magnet will be reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO025
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MOPRI003	Positron Yield Optimization by Adjusting the Components Offset and Orientation	576
	L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama KEK, Ibaraki, Japan S. Ushimoto Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003
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MOPRI004	SuperKEKB Positron Source Construction Status	579
	T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, H. Katagiri, M. Kikuchi, H. Koiso, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, M. Sato, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The KEKB positron source is under the upgrade for SuperKEKB. The previous positron production target and capture section have been removed and the new system is constructed at a location forty meters upstream to have sufficient energy margin for beam injection to the newly introduced damping ring. A flux concentrator is introduced in the new capture section to make an adiabatic matching system. Large aperture (30mm in diameter) S-band accelerating structures are introduced in the capture section and in the subsequent accelerator module to enlarge the transverse phase space acceptance. The beam focusing system of quadrupoles is also upgraded for a comparable beam acceptance to that of the capture section. This paper reports on the status of the SuperKEKB positron source construction and the preliminary positron beam commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI004
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Paper

Title

Page

Upgrade Status of Injector LINAC for SuperKEKB

59

T. Miura, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The SuperKEKB collider is under construction to achieve 40-times higher luminosity than that of previous KEKB collider. The injector LINAC should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron for SuperKEKB based on a nano-beam scheme. A photocathode RF-gun for low emittance electron beam has been already installed and the commissioning has started. The construction of positron capture section using a flux-concentrator and the dumping ring for low emittance positron beam is in progress. The simultaneous top-up injections to four storage-rings including photon factories is also required. In the upstream of dumping ring, the compatible optics between positron and electron has been designed. In the downstream of dumping ring, RF phase, focusing, and steering magnets will be switched by pulse to pulse against each beam-mode for optimising beam-transportation. This paper describes recent upgrade status toward the SuperKEKB.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO001

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MOPRO023

SuperKEKB Beam abort System

116

T. Mimashi, N. Iida, M. Kikuchi, T. Mori
KEK, Ibaraki, Japan
K. Abe
Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan
A. Sasagawa
KYOCERA Corporation, Higashiomi-city, Shiga, Japan
A. Tokuchi
Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan

The abort system of the SuperKEKB is described. The beam abort system consists of the beam abort kicker magnets, pulsed quadrupole magnets, a lambertson septum magnet and extracted window. The dumped beam is extracted with beam abort kicker through the extraction window. The pulsed quadrupole magnets make the beam spot size large at the window. The damages of the extraction window is tested with KEKB beam. The pulsed kicker power supply is under development.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO023

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MOPRO024

The Beam Test for the Ti Extraction Window Damage

119

T. Mimashi, N. Iida, M. Kikuchi
KEK, Ibaraki, Japan

For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO024

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MOPRO025

Electron Beam Injection System for SuperKEKB Main Ring

122

T. Mori, N. Iida, M. Kikuchi, T. Mimashi, Y. Sakamoto, S. Takasaki, M. Tawada
KEK, Ibaraki, Japan

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\mbox{nm}. The emittance of the injected beam is ε=1.46\mbox{nm}. To acheave 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 sections is the injection system. It has been pointed out that the injected beam has possibility of leading to blowup in the ring, which is caused by a beam-beam interaction with the stored positron beam. To avoid the beam blowup, the synchrotron injection is adopted as a backup option. The orbit of the electron injection beam has been designed and the septum magnet prototype has been constructed. The optics study for electron injection and the current R&D status for the septum magnet will be reported in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO025

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MOPRI003

Positron Yield Optimization by Adjusting the Components Offset and Orientation

576

L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama
KEK, Ibaraki, Japan
S. Ushimoto
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI004

SuperKEKB Positron Source Construction Status

579

T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, H. Katagiri, M. Kikuchi, H. Koiso, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, M. Sato, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The KEKB positron source is under the upgrade for SuperKEKB. The previous positron production target and capture section have been removed and the new system is constructed at a location forty meters upstream to have sufficient energy margin for beam injection to the newly introduced damping ring. A flux concentrator is introduced in the new capture section to make an adiabatic matching system. Large aperture (30mm in diameter) S-band accelerating structures are introduced in the capture section and in the subsequent accelerator module to enlarge the transverse phase space acceptance. The beam focusing system of quadrupoles is also upgraded for a comparable beam acceptance to that of the capture section. This paper reports on the status of the SuperKEKB positron source construction and the preliminary positron beam commissioning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI004

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