PAC2013 - List of Authors (Takatomi, T.)

Paper

Title

Page

Study on 2 Cell RF-Deflector Cavity for Ultra-short Electron Bunch Measurement

628

T. Takahashi, Y. Nishimura, M. Nishiyama, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan
T. Takatomi, J. Urakawa
KEK, Ibaraki, Japan

Funding: Work supported by JSPS Grant-in-Aid for Scientific Research (A) 10001690 and the Quantum Beam Technology Program of MEXT.
We have been studying on a system to measure ultra-short electron beam bunch length at Waseda University. We adopted the rf-deflector system which can convert the longitudinal distribution to transverse by sweeping the electron bunch. We used HFSS for designing the rf-deflector cavity and GPT for beam tracking. In order to achieve the desired magnitude of magnetic field in the rf-deflector, we decided to use a 2-cells cavity of rectangular structure. Finally we optimized the design for the rf-deflector which is operating on π-mode, standing wave, dipole (TM120) mode at 2856 MHz. We have confirmed this rf-deflector has enough performance, which is 100 femt seconds bunch measurement, by GPT simulations. Now we have finished manufacturing with the collaboration of High Energy Accelerator Research Organization (KEK). We could adjust resonant frequency to 2856 MHz and combine the waveguide with the rf-deflector precisely. We will integrate the rf-deflector into an S-band Cs-Te photocathode rf electron gun system in Waseda University, and carry out bunch length measurement in this summer. In this conference, we will report the present progresses and future plan.

WEOBA2

Ultra-Short Electron Bunch Generation by a Photocathode RF Gun

719

M. Mizugaki, Y. Koshiba, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan
R. Kuroda
AIST, Tsukuba, Ibaraki, Japan
T. Takatomi, J. Urakawa
KEK, Ibaraki, Japan

We have been studying on the accelerator physics at Waseda University with BNL type 1.6cell rf gun. Such photocathode rf gun can generate low emittance and short bunch electron beam. Generating ultra-short electron bunch (shorter than 1ps) in a compact accelerator system would be meaningful because some applications need to be miniaturized, THz imaging, for example. However a short laser pulse cannot generate the bunch length of less than 1ps due to the space charge effects. So as to generate ultra-short electron bunch in compact system, we have newly designed Energy Chirping Cell attached rf gun (ECC rf gun). ECC is attached subsequently to the 1.6 cell. The role of ECC is to chirp the electron energy so that the electron bunch is compressed by velocity difference as it drifts. Simulation results show ECC rf gun can accelerate100pC electron bunch with the bunch length shorter than 100fs. We have successfully measured the coherent THz light by synchrotron radiation and transition radiation. Therefore, we inferred that the bunch was compressed into shorter than 1ps. In this conference, we will report the results of the bunch length measurement, present progresses and future plans.
JSPS Grant-in-Aid for Young Science (B) 23740203 and Scientific Research (A) 10001619

Slides WEOBA2 [7.527 MB]

Paper	Title	Page
TUPSM01	Study on 2 Cell RF-Deflector Cavity for Ultra-short Electron Bunch Measurement	628
	T. Takahashi, Y. Nishimura, M. Nishiyama, K. Sakaue, M. Washio Waseda University, Tokyo, Japan T. Takatomi, J. Urakawa KEK, Ibaraki, Japan
	Funding: Work supported by JSPS Grant-in-Aid for Scientific Research (A) 10001690 and the Quantum Beam Technology Program of MEXT. We have been studying on a system to measure ultra-short electron beam bunch length at Waseda University. We adopted the rf-deflector system which can convert the longitudinal distribution to transverse by sweeping the electron bunch. We used HFSS for designing the rf-deflector cavity and GPT for beam tracking. In order to achieve the desired magnitude of magnetic field in the rf-deflector, we decided to use a 2-cells cavity of rectangular structure. Finally we optimized the design for the rf-deflector which is operating on π-mode, standing wave, dipole (TM120) mode at 2856 MHz. We have confirmed this rf-deflector has enough performance, which is 100 femt seconds bunch measurement, by GPT simulations. Now we have finished manufacturing with the collaboration of High Energy Accelerator Research Organization (KEK). We could adjust resonant frequency to 2856 MHz and combine the waveguide with the rf-deflector precisely. We will integrate the rf-deflector into an S-band Cs-Te photocathode rf electron gun system in Waseda University, and carry out bunch length measurement in this summer. In this conference, we will report the present progresses and future plan.

WEOBA2	Ultra-Short Electron Bunch Generation by a Photocathode RF Gun	719
	M. Mizugaki, Y. Koshiba, K. Sakaue, M. Washio Waseda University, Tokyo, Japan R. Kuroda AIST, Tsukuba, Ibaraki, Japan T. Takatomi, J. Urakawa KEK, Ibaraki, Japan
	We have been studying on the accelerator physics at Waseda University with BNL type 1.6cell rf gun. Such photocathode rf gun can generate low emittance and short bunch electron beam. Generating ultra-short electron bunch (shorter than 1ps) in a compact accelerator system would be meaningful because some applications need to be miniaturized, THz imaging, for example. However a short laser pulse cannot generate the bunch length of less than 1ps due to the space charge effects. So as to generate ultra-short electron bunch in compact system, we have newly designed Energy Chirping Cell attached rf gun (ECC rf gun). ECC is attached subsequently to the 1.6 cell. The role of ECC is to chirp the electron energy so that the electron bunch is compressed by velocity difference as it drifts. Simulation results show ECC rf gun can accelerate100pC electron bunch with the bunch length shorter than 100fs. We have successfully measured the coherent THz light by synchrotron radiation and transition radiation. Therefore, we inferred that the bunch was compressed into shorter than 1ps. In this conference, we will report the results of the bunch length measurement, present progresses and future plans. JSPS Grant-in-Aid for Young Science (B) 23740203 and Scientific Research (A) 10001619
	Slides WEOBA2 [7.527 MB]