IPAC2014 - List of Authors (Konomi, T.)

Paper	Title	Page
MOPRI034	Development of temporal response measurement system for transmission-type spin-polarized photocathodes	670
	T. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan M. Adachi KEK, Ibaraki, Japan X.G. Jin Institute for Advanced Research, Nagoya, Japan M. Katoh, T. Konomi UVSOR, Okazaki, Japan Y. Okano IMS, Okazaki, Japan
	Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved,. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode*. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results. T. Nakanishi, The XXI International LINAC Conference(1998) Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004 * Xiuguang Jin, Applied Physics Express 6 (2013) 015801
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI035	Development of the Photocathode LiTi2O4 and Evaluations of the Initial Emittance	673
	R. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan T. Hitosugi, S. Shiraki Tohoku Uneversity, WPI-AIMR, Sendai, Japan E. Kako, Y. Kobayashi, S. Yamaguchi KEK, Ibaraki, Japan M. Katoh, T. Konomi, T. Tokushi UVSOR, Okazaki, Japan Y. Okano IMS, Okazaki, Japan
	In UVSOR, the X-ray free electron laser (XFEL) based on linear accelerator with high pulse repetition about 1MHz has been designed as a candidate for the next radiation sources. We thought a combination of superconducting RF cavity and photocathode is an optimal electron gun for the new accelerator. For this electron gun, we propose a back-illuminated multi-alkali* photocathode with transparent superconductor LiTi2O4*. The reason for using LiTi2O4 is to reflect RF by using feature of penetration depth of superconductor, which is defined from London equation. This feature protects optical components from RF damage. However, LiTi2O4 is a new material and properties are not clear. We have measured the basic properties of this photocathode, such as magnetic susceptibility measurement and photoelectron spectrometry, etc. In this conference, we will explain the detail of the concept and advantage of this cathode, and show the result measured about the basic properties of this photocathode focusing on the initial emittance measurement. A. V. Lyashenko et al. JINST 4 P07005 (2009) ** Kumatani et al. APL 101 (2012) 123103″
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI042	Numerical Study of the Microbunching Instability at UVSOR-III: Influence of the Resistive and Inductive Impedances	1656
SUSPSNE061	use link to see paper's listing under its alternate paper code
	E. Roussel, S. Bielawski, C. Evain, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France M. Adachi, M. Katoh, S.I. Kimura, T. Konomi UVSOR, Okazaki, Japan M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan K.S. Ilin, J. Raasch, A. Scheuring, M. Siegel, P. Thoma KIT, Karlsruhe, Germany H. Zen Kyoto University, Kyoto, Japan
	At high charge, relativistic electron bunches circulating in storage rings undergo an instability, the so-called microbunching or the CSR (Coherent Synchrotron Radiation) instability. This instability is due to the interaction of the electrons with their own radiation and leads to the formation of microstructures (at millimeter scale) in the longitudinal phase space. Thanks to a new type of detector, based on superconducting thin film YBCO, it is now possible to observe directly these microstructures and follow their temporal evolution. These experimental observations open a new way to make severe comparisons with theory. Here we present results of the modeling of the dynamics at UVSOR-III using a one dimensional Vlasov-Fokker-Planck equation. We show that to obtain a relatively good agreement between numerical simulations and experiments, we have to take into account several types of impedance such as the shielded CSR impedance but also the resistive and inductive impedances. First Direct, Real Time, Recording of the CSR Pulses Emitted During the Microbunching Instability, using Thin Film YBCO Detectors at UVSOR-III, IPAC2014
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME125	Electrical Field Sensitive High-Tc YBCO Detector for Real-time Observation of CSR	3533
	J. Raasch, K.S. Ilin, Y.-L. Mathis, A.-S. Müller, A. Scheuring, M. Siegel, N.J. Smale, P. Thoma KIT, Karlsruhe, Germany S. Bielawski, C. Evain, E. Roussel, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France B. Holzapfel Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany M. Hosaka, N. Yamamoto Nagoya University, Nagoya, Japan K. Iida Leibniz Institute for Solid State and Materials Research Dresden, Dresden, Germany M. Katoh, S.I. Kimura, T. Konomi UVSOR, Okazaki, Japan H. Zen Kyoto University, Kyoto, Japan
	Funding: We thank Agilent Technologies & Tektronix for supplying oscilloscopes. The work was supported by BMBF (05K2010), ANR (2010 blanc 042301), MEXT (Quantum Beam Tech. Prog.), IMS (Int. Collab. Prog.). High-Tc thin-film YBa2Cu3O7-x (YBCO) detectors were deployed for the real-time observation of Coherent Synchrotron Radiation (CSR). Due to enhanced fabrication techniques enabling the patterning of sub-μm sized detector areas responsivity values as high as 1V/pJ for pulsed THz excitations have been achieved at the ANKA synchrotron facility at the Karlsruhe Institute of Technology (KIT). Response of the detectors is linear over the whole dynamic range of the IR1 beamline. Combining the picosecond scaled response mechanism of the high-temperature superconductor YBa2Cu3O7-x (YBCO) to THz excitations with broad-band readout a temporal resolution of 15 ps full width at half maximum (FWHM) was reached. Real-time resolution of CSR single shots was observed at ANKA and UVSOR-III, the synchrotron facility of the Institute of Molecular Science in Okazaki, Japan.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME125
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Development of temporal response measurement system for transmission-type spin-polarized photocathodes

670

T. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
M. Adachi
KEK, Ibaraki, Japan
X.G. Jin
Institute for Advanced Research, Nagoya, Japan
M. Katoh, T. Konomi
UVSOR, Okazaki, Japan
Y. Okano
IMS, Okazaki, Japan

Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved*,**. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode***. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results.
* T. Nakanishi, The XXI International LINAC Conference(1998)
** Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004
*** Xiuguang Jin, Applied Physics Express 6 (2013) 015801

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034

Export •

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

MOPRI035

Development of the Photocathode LiTi2O4 and Evaluations of the Initial Emittance

673

R. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
T. Hitosugi, S. Shiraki
Tohoku Uneversity, WPI-AIMR, Sendai, Japan
E. Kako, Y. Kobayashi, S. Yamaguchi
KEK, Ibaraki, Japan
M. Katoh, T. Konomi, T. Tokushi
UVSOR, Okazaki, Japan
Y. Okano
IMS, Okazaki, Japan

In UVSOR, the X-ray free electron laser (XFEL) based on linear accelerator with high pulse repetition about 1MHz has been designed as a candidate for the next radiation sources. We thought a combination of superconducting RF cavity and photocathode is an optimal electron gun for the new accelerator. For this electron gun, we propose a back-illuminated multi-alkali* photocathode with transparent superconductor LiTi2O4**. The reason for using LiTi2O4 is to reflect RF by using feature of penetration depth of superconductor, which is defined from London equation. This feature protects optical components from RF damage. However, LiTi2O4 is a new material and properties are not clear. We have measured the basic properties of this photocathode, such as magnetic susceptibility measurement and photoelectron spectrometry, etc. In this conference, we will explain the detail of the concept and advantage of this cathode, and show the result measured about the basic properties of this photocathode focusing on the initial emittance measurement.
* A. V. Lyashenko et al. JINST 4 P07005 (2009)
** Kumatani et al. APL 101 (2012) 123103″

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI035

Export •

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

TUPRI042

Numerical Study of the Microbunching Instability at UVSOR-III: Influence of the Resistive and Inductive Impedances

1656

SUSPSNE061

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

E. Roussel, S. Bielawski, C. Evain, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
M. Adachi, M. Katoh, S.I. Kimura, T. Konomi
UVSOR, Okazaki, Japan
M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
K.S. Ilin, J. Raasch, A. Scheuring, M. Siegel, P. Thoma
KIT, Karlsruhe, Germany
H. Zen
Kyoto University, Kyoto, Japan

At high charge, relativistic electron bunches circulating in storage rings undergo an instability, the so-called microbunching or the CSR (Coherent Synchrotron Radiation) instability. This instability is due to the interaction of the electrons with their own radiation and leads to the formation of microstructures (at millimeter scale) in the longitudinal phase space. Thanks to a new type of detector, based on superconducting thin film YBCO, it is now possible to observe directly these microstructures and follow their temporal evolution*. These experimental observations open a new way to make severe comparisons with theory. Here we present results of the modeling of the dynamics at UVSOR-III using a one dimensional Vlasov-Fokker-Planck equation. We show that to obtain a relatively good agreement between numerical simulations and experiments, we have to take into account several types of impedance such as the shielded CSR impedance but also the resistive and inductive impedances.
* First Direct, Real Time, Recording of the CSR Pulses Emitted During the Microbunching Instability, using Thin Film YBCO Detectors at UVSOR-III, IPAC2014

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI042

Export •

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

THPME125

Electrical Field Sensitive High-Tc YBCO Detector for Real-time Observation of CSR

3533

J. Raasch, K.S. Ilin, Y.-L. Mathis, A.-S. Müller, A. Scheuring, M. Siegel, N.J. Smale, P. Thoma
KIT, Karlsruhe, Germany
S. Bielawski, C. Evain, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Holzapfel
Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
M. Hosaka, N. Yamamoto
Nagoya University, Nagoya, Japan
K. Iida
Leibniz Institute for Solid State and Materials Research Dresden, Dresden, Germany
M. Katoh, S.I. Kimura, T. Konomi
UVSOR, Okazaki, Japan
H. Zen
Kyoto University, Kyoto, Japan

Funding: We thank Agilent Technologies & Tektronix for supplying oscilloscopes. The work was supported by BMBF (05K2010), ANR (2010 blanc 042301), MEXT (Quantum Beam Tech. Prog.), IMS (Int. Collab. Prog.).
High-Tc thin-film YBa2Cu3O7-x (YBCO) detectors were deployed for the real-time observation of Coherent Synchrotron Radiation (CSR). Due to enhanced fabrication techniques enabling the patterning of sub-μm sized detector areas responsivity values as high as 1V/pJ for pulsed THz excitations have been achieved at the ANKA synchrotron facility at the Karlsruhe Institute of Technology (KIT). Response of the detectors is linear over the whole dynamic range of the IR1 beamline. Combining the picosecond scaled response mechanism of the high-temperature superconductor YBa2Cu3O7-x (YBCO) to THz excitations with broad-band readout a temporal resolution of 15 ps full width at half maximum (FWHM) was reached. Real-time resolution of CSR single shots was observed at ANKA and UVSOR-III, the synchrotron facility of the Institute of Molecular Science in Okazaki, Japan.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME125

Export •

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