IPAC2022 - List of Authors (Sakaue, K.)

Paper	Title	Page
WEPOPT025	Flat Beam Generation with the Phase Space Rotation Technique at KEK-STF	1897
	M. Kuriki, Z.J. Liptak HU/AdSM, Higashi-Hiroshima, Japan S. Aramoto Hiroshima University, Higashi-Hiroshima, Japan H. Hayano, X.J. Jin, Y. Seimiya, N. Yamamoto, Y. Yamamoto KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan K. Sakaue The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan M. Washio RISE, Tokyo, Japan
	Flat beam generation from angular momentum dominated beam with a phase-space rotation technique is an unique method to manipulate the phase-space distribution of beam. As an application, the asymmetric emittance beam generation for linear colliders is considered to compensate the Beamstrahlung effect at Interaction point. By using this technique, the asymmetric beam can be generated directly with the injector, instead of radiation damping with a huge damping ring. We present the result of a proof-of-principle experiment at KEK-STF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT025
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOST013	Development of a Detection System for Quasi-Monochromatic THz Pulse by a Spatially Modulated Electron Beam	2469
SUSPMF016	use link to see paper's listing under its alternate paper code
	K. Murakoshi, Y. Koshiba, Y. Tadenuma, P. Wang, M. Washio Waseda University, Tokyo, Japan R. Kuroda AIST, Tsukuba, Japan K. Sakaue The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
	We have studied the generation of the broadband THz pulse using a compact linear accelerator. The THz pulse is generated by control of an electron beam angle to Cherenkov radiation angle. In addition, we have succeeded in producing a quasi-monochromatic THz pulse by the spatially modulated electron beam by passing through a slit. This work aims to develop a detection system to elucidate the spectrum of the quasi-monochromatic THz pulse. To detect it stably in a noisy radiation environment, the stability of probe laser system for Electro Optic sampling and timing synchronization system are important. In this conference, the generation method of each THz pulses, the results of development of detection system, and future prospect will be reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST013
About •	Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 24 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOPT029	Study on the Performance Improvement of Alkali Antimonide Photocathodes for Radio Frequency Electron Guns	2640
	R. Fukuoka, K. Ezawa, Y. Koshiba, M. Washio Waseda University, Tokyo, Japan K. Sakaue The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
	Semiconductor photocathodes such as Cs-Te and Cs-K-Sb are used as electron sources in accelerators to generate high brightness beams using radio frequency (rf) electron guns. Alkali antimonide photocathodes have a high quantum efficiency (Q.E.) of ~10%, and their excitation wavelength is in the visible light region (532 nm), so that they are expected to reduce the requirements on the optical system and increase the amount of charge compared to Cs-Te. However, alkali antimonide photocathodes have a short lifetime and degrade under poor vacuum conditions, so it is essential to improve durability by protective film coatings. Therefore, we are currently working on the fabrication of high Q.E. alkali antimonide photocathodes that can withstand the Q.E. reduction during coating. In this presentation, we will report the results of comparison between the fabricated alkali antimonide photocathode and Cs-Te photocathode, and future prospects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT029
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOMS060	Development of Analytical Light Source for Construction of Femtosecond Pulse Radiolysis System Using Er Fiber Laser	3109
	Y. Kaneko, Y. Koshiba, K. Sakaue, M. Sato, M. Washio Waseda University, Tokyo, Japan K. Sakaue The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
	We are trying to elucidate the initial process of radiation chemical reactions, which is considered to be an unknown area. One of the methods to elucidate this initial process is pulse radiolysis. In pulse radiolysis, a substance is irradiated with ionizing radiation and at the same time irradiated with analytical light, and the absorption spectrum of the light can be traced back in time to the active species. However, the radiation chemical reaction starts in a very short time, and the pulse radiolysis system needs to have the same time resolution. Therefore, the analytical light should be ultra-short pulses. In addition, the absorption wavelength of the substance is not always known. Hence, the wavelength range of the analytical light should be broad. Since the absorption wavelengths of important active species are in the visible light region, it is desirable to cover the visible light region as well. We believe that supercontinuum light generated from the second harmonic of the Er fiber laser is the best analytical light to meet these requirements. In this presentation, we describe the current status of the development of the supercontinuum light generation and future prospects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS060
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Flat Beam Generation with the Phase Space Rotation Technique at KEK-STF

1897

M. Kuriki, Z.J. Liptak
HU/AdSM, Higashi-Hiroshima, Japan
S. Aramoto
Hiroshima University, Higashi-Hiroshima, Japan
H. Hayano, X.J. Jin, Y. Seimiya, N. Yamamoto, Y. Yamamoto
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
M. Washio
RISE, Tokyo, Japan

Flat beam generation from angular momentum dominated beam with a phase-space rotation technique is an unique method to manipulate the phase-space distribution of beam. As an application, the asymmetric emittance beam generation for linear colliders is considered to compensate the Beamstrahlung effect at Interaction point. By using this technique, the asymmetric beam can be generated directly with the injector, instead of radiation damping with a huge damping ring. We present the result of a proof-of-principle experiment at KEK-STF.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT025

About •

Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022

Cite •

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

THPOST013

Development of a Detection System for Quasi-Monochromatic THz Pulse by a Spatially Modulated Electron Beam

2469

SUSPMF016

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

K. Murakoshi, Y. Koshiba, Y. Tadenuma, P. Wang, M. Washio
Waseda University, Tokyo, Japan
R. Kuroda
AIST, Tsukuba, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

We have studied the generation of the broadband THz pulse using a compact linear accelerator. The THz pulse is generated by control of an electron beam angle to Cherenkov radiation angle. In addition, we have succeeded in producing a quasi-monochromatic THz pulse by the spatially modulated electron beam by passing through a slit. This work aims to develop a detection system to elucidate the spectrum of the quasi-monochromatic THz pulse. To detect it stably in a noisy radiation environment, the stability of probe laser system for Electro Optic sampling and timing synchronization system are important. In this conference, the generation method of each THz pulses, the results of development of detection system, and future prospect will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST013

About •

Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 24 June 2022

Cite •

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

THPOPT029

Study on the Performance Improvement of Alkali Antimonide Photocathodes for Radio Frequency Electron Guns

2640

R. Fukuoka, K. Ezawa, Y. Koshiba, M. Washio
Waseda University, Tokyo, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

Semiconductor photocathodes such as Cs-Te and Cs-K-Sb are used as electron sources in accelerators to generate high brightness beams using radio frequency (rf) electron guns. Alkali antimonide photocathodes have a high quantum efficiency (Q.E.) of ~10%, and their excitation wavelength is in the visible light region (532 nm), so that they are expected to reduce the requirements on the optical system and increase the amount of charge compared to Cs-Te. However, alkali antimonide photocathodes have a short lifetime and degrade under poor vacuum conditions, so it is essential to improve durability by protective film coatings. Therefore, we are currently working on the fabrication of high Q.E. alkali antimonide photocathodes that can withstand the Q.E. reduction during coating. In this presentation, we will report the results of comparison between the fabricated alkali antimonide photocathode and Cs-Te photocathode, and future prospects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT029

About •

Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022

Cite •

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

THPOMS060

Development of Analytical Light Source for Construction of Femtosecond Pulse Radiolysis System Using Er Fiber Laser

3109

Y. Kaneko, Y. Koshiba, K. Sakaue, M. Sato, M. Washio
Waseda University, Tokyo, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan

We are trying to elucidate the initial process of radiation chemical reactions, which is considered to be an unknown area. One of the methods to elucidate this initial process is pulse radiolysis. In pulse radiolysis, a substance is irradiated with ionizing radiation and at the same time irradiated with analytical light, and the absorption spectrum of the light can be traced back in time to the active species. However, the radiation chemical reaction starts in a very short time, and the pulse radiolysis system needs to have the same time resolution. Therefore, the analytical light should be ultra-short pulses. In addition, the absorption wavelength of the substance is not always known. Hence, the wavelength range of the analytical light should be broad. Since the absorption wavelengths of important active species are in the visible light region, it is desirable to cover the visible light region as well. We believe that supercontinuum light generated from the second harmonic of the Er fiber laser is the best analytical light to meet these requirements. In this presentation, we describe the current status of the development of the supercontinuum light generation and future prospects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS060

About •

Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022

Cite •

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