IPAC2016 - List of Authors (Shibuya, T.)

Paper	Title	Page
WEPMY040	Fabrication of Two Dimensional Nano-Scale Photocathode Arrays in Transparent Conductor for High Coherence Beam Generation	2645
SUPSS039	use link to see paper's listing under its alternate paper code
	T. Shibuya TIT, Tokyo, Japan N. Hayashizaki RLNR, Tokyo, Japan M. Yoshida KEK, Ibaraki, Japan
	Electron beam quality for particle source of diffractometer is mainly characterized by transverse and longitudinal coherent length, beam current density and so on. In order to improve a transverse coherent length, it is practically essential to minimize electrons emission area size as small as possible. However, the size of photoemission area is limited by focused laser beam size on the surface of cathode, and the scale is several microns. Aim to get definite overlap between the focused laser and emitters for effective irradiation, as well as to realize generation of nano-scale size electron beam, nano-scale photocathode arrays in transparent conductor are essential. Therefore, I propose to fabricate the nano-scale emission area in replace of limiting the focused laser size on the photocathode for achieving high coherence beam. The fabrication process of this novel nano-scale emitter configuration and its fundamental properties are presented in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY040
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THPMY041	Neodymium and Ytterbium Hybrid Solid Laser of RF Gun for SuperKEKB	3748
	X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida, R. Zhang KEK, Ibaraki, Japan T. Shibuya TIT, Tokyo, Japan
	The electrum beam of the repetition rate of 50 Hz double-bunch is requested for injector linac of SuperKEKB. By development of the Yb-doped laser system, more than 5.0 nC and 3.0 nC electron beam with single-bunch has been generated in the 5 Hz and 25 Hz respectively. Also more than 1.0 nC electron with double-bunch has been obtained in 25 Hz. The Yb-doped laser system is already for commissioning for the linac. Next, a new laser system is development to improve the stability and reliability. The laser system starts with a 50 MHz Yb-doped fiber oscillator with the all normal dispersion (ANDi) structure. A transmission grating pair stretcher was employed to expend pulse to ~30 ps and separate the pulse to two parts with the center wavelength of 1030 nm and 1064 nm. Then the two kinds of pulses can be amplified by Yb:YAG and Nd:YAG crystals respectively. The weak pulses were amplified by the Yb-doped fiber amplifier, and reduced repetition rate by a semiconductor optics amplifier (SOA) pulse picker. To obtain the mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier and a Nd:YAG rod regenerative solid-state amplifier were employed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY041
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THPOW056	Fiber Laser Development for Dielectric Laser-driven Accelerator and Electron Beam Source	4070
SUPSS024	use link to see paper's listing under its alternate paper code
	H. Okamoto, S. Otsuki The University of Tokyo, Tokyo, Japan K. Koyama, M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan D. Satoh, T. Shibuya TIT, Tokyo, Japan M. Yoshida KEK, Ibaraki, Japan
	Our group is aiming for developing a table-top electronμbeam source, whose beam size is micro-meter order so that we can irradiate just the nuclei of cells (1μm) and observe the behavior in real time. This beam source will be realized by dielectric laser-driven accelerators(DLAs), which is expected to produce acceleration gradients of ~GV/m. To drive these accelerators, ultra-short pulse laser has to be incident to the structure. We chose Ytterbium (Yb) fiber laser for generating and amplifying ultra-short laser pulse, which has high quantum efficiency and can easily pumped by LD, and is proper to produce ultra-short pulses because of its wide-band oscillation. We succeeded in getting ultra-short pulse (central wavelength: {1030} nm, average output: 10 W, pulse duration: ~10 ps, reputation rate: 84 MHz) from Yb fiber laser system. Also in order to make electron bunch by photo cathode, we then converted the obtained IR laser to UV of 258 nm (4ω) using BBO and LBO crystals. We are planning to amplify the pulses by Yb:YAG in future, which has its amplification band in {1030} nm. K. Koyama el al., "Design Of Photonic Crystal Accelerator For Radiation Biology," IPAC'12 Proceedings (2014)
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW056
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Paper

Title

Page

Fabrication of Two Dimensional Nano-Scale Photocathode Arrays in Transparent Conductor for High Coherence Beam Generation

2645

SUPSS039

use link to see paper's listing under its alternate paper code

T. Shibuya
TIT, Tokyo, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
M. Yoshida
KEK, Ibaraki, Japan

Electron beam quality for particle source of diffractometer is mainly characterized by transverse and longitudinal coherent length, beam current density and so on. In order to improve a transverse coherent length, it is practically essential to minimize electrons emission area size as small as possible. However, the size of photoemission area is limited by focused laser beam size on the surface of cathode, and the scale is several microns. Aim to get definite overlap between the focused laser and emitters for effective irradiation, as well as to realize generation of nano-scale size electron beam, nano-scale photocathode arrays in transparent conductor are essential. Therefore, I propose to fabricate the nano-scale emission area in replace of limiting the focused laser size on the photocathode for achieving high coherence beam. The fabrication process of this novel nano-scale emitter configuration and its fundamental properties are presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY040

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THPMY041

Neodymium and Ytterbium Hybrid Solid Laser of RF Gun for SuperKEKB

3748

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida, R. Zhang
KEK, Ibaraki, Japan
T. Shibuya
TIT, Tokyo, Japan

The electrum beam of the repetition rate of 50 Hz double-bunch is requested for injector linac of SuperKEKB. By development of the Yb-doped laser system, more than 5.0 nC and 3.0 nC electron beam with single-bunch has been generated in the 5 Hz and 25 Hz respectively. Also more than 1.0 nC electron with double-bunch has been obtained in 25 Hz. The Yb-doped laser system is already for commissioning for the linac. Next, a new laser system is development to improve the stability and reliability. The laser system starts with a 50 MHz Yb-doped fiber oscillator with the all normal dispersion (ANDi) structure. A transmission grating pair stretcher was employed to expend pulse to ~30 ps and separate the pulse to two parts with the center wavelength of 1030 nm and 1064 nm. Then the two kinds of pulses can be amplified by Yb:YAG and Nd:YAG crystals respectively. The weak pulses were amplified by the Yb-doped fiber amplifier, and reduced repetition rate by a semiconductor optics amplifier (SOA) pulse picker. To obtain the mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier and a Nd:YAG rod regenerative solid-state amplifier were employed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY041

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

THPOW056

Fiber Laser Development for Dielectric Laser-driven Accelerator and Electron Beam Source

4070

SUPSS024

use link to see paper's listing under its alternate paper code

H. Okamoto, S. Otsuki
The University of Tokyo, Tokyo, Japan
K. Koyama, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
D. Satoh, T. Shibuya
TIT, Tokyo, Japan
M. Yoshida
KEK, Ibaraki, Japan

Our group is aiming for developing a table-top electronμbeam source, whose beam size is micro-meter order so that we can irradiate just the nuclei of cells (1μm) and observe the behavior in real time. This beam source will be realized by dielectric laser-driven accelerators(DLAs), which is expected to produce acceleration gradients of ~GV/m. To drive these accelerators, ultra-short pulse laser has to be incident to the structure*. We chose Ytterbium (Yb) fiber laser for generating and amplifying ultra-short laser pulse, which has high quantum efficiency and can easily pumped by LD, and is proper to produce ultra-short pulses because of its wide-band oscillation. We succeeded in getting ultra-short pulse (central wavelength: {1030} nm, average output: 10 W, pulse duration: ~10 ps, reputation rate: 84 MHz) from Yb fiber laser system. Also in order to make electron bunch by photo cathode, we then converted the obtained IR laser to UV of 258 nm (4ω) using BBO and LBO crystals. We are planning to amplify the pulses by Yb:YAG in future, which has its amplification band in {1030} nm.
* K. Koyama el al., "Design Of Photonic Crystal Accelerator For Radiation Biology," IPAC'12 Proceedings (2014)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW056

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