IPAC2018 - List of Authors (Tanaka, T.)

Paper	Title	Page
THPAL061	Simulation of Pulsed Temperature Rise in Cryogenic Copper RF Cavity Achieving a Very High Accelerating Field	3788
	T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo LEBRA, Funabashi, Japan
	A cryogenic C-band photocathode RF electron gun cavity has been studied at Nihon University LEBRA in cooperation with KEK. The RF properties of a cold model measured at 20 K have shown good agreement with those expected from computer simulations using the cavity surface resistance predicted by the theory of the anomalous skin effect. Recent studies on the vacuum RF breakdown at high electric fields suggest that the temperature in the cavity surface during the high power RF pulse has a significant effect on the behavior of the breakdown rate. In order to investigate the breakdown property of the cryogenic cavity aiming at a very high accelerating field with as low breakdown rate as possible, one-dimensional simulations of the temperature rise in the cavity surface have been done for various combinations of the RF pulse width and the peak input RF power. The evaluation will be taken into consideration in the design of a new high power cryogenic cavity that has basically the same configuration with the cold model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL061
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THPMK022	Simulation for THz Coherent Undulator Radiation from Combination of Velocity Bunchings	4345
	Y. Sumitomo, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Takahashi, T. Tanaka LEBRA, Funabashi, Japan
	We study the effect of a combination of velocity bunchings and its application to THz coherent undulator radiation at LEBRA, Nihon U. by simulations. The velocity bunching is a technique that is commonly used to make the bunch length shorter at lower energies. However, since one velocity bunching has a correlation between bunch energy and length, we may not have so much room to change energies to obtain different coherent radiation wavelengths. Hence we propose a combination of velocity bunchings, that relaxes the restrictive correlation. We have three 4m traveling-wave accelerator tubes at LEBRA, Nihon U. The undulator is installed after the acceleration tubes and 2 x 45 degree bending magnets. Since the design of current undulator requires less than 25 MeV beam energy to obtain the radiation at THz region, the velocity bunching is reasonable for coherent radiation. We show the simulation results of a combination of velocity bunchings of the three tubes and the magnetic bunching at bending magnets, suitable for the coherent undulator radiation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK022
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Simulation of Pulsed Temperature Rise in Cryogenic Copper RF Cavity Achieving a Very High Accelerating Field

3788

T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo
LEBRA, Funabashi, Japan

A cryogenic C-band photocathode RF electron gun cavity has been studied at Nihon University LEBRA in cooperation with KEK. The RF properties of a cold model measured at 20 K have shown good agreement with those expected from computer simulations using the cavity surface resistance predicted by the theory of the anomalous skin effect. Recent studies on the vacuum RF breakdown at high electric fields suggest that the temperature in the cavity surface during the high power RF pulse has a significant effect on the behavior of the breakdown rate. In order to investigate the breakdown property of the cryogenic cavity aiming at a very high accelerating field with as low breakdown rate as possible, one-dimensional simulations of the temperature rise in the cavity surface have been done for various combinations of the RF pulse width and the peak input RF power. The evaluation will be taken into consideration in the design of a new high power cryogenic cavity that has basically the same configuration with the cold model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL061

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

THPMK022

Simulation for THz Coherent Undulator Radiation from Combination of Velocity Bunchings

4345

Y. Sumitomo, K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Takahashi, T. Tanaka
LEBRA, Funabashi, Japan

We study the effect of a combination of velocity bunchings and its application to THz coherent undulator radiation at LEBRA, Nihon U. by simulations. The velocity bunching is a technique that is commonly used to make the bunch length shorter at lower energies. However, since one velocity bunching has a correlation between bunch energy and length, we may not have so much room to change energies to obtain different coherent radiation wavelengths. Hence we propose a combination of velocity bunchings, that relaxes the restrictive correlation. We have three 4m traveling-wave accelerator tubes at LEBRA, Nihon U. The undulator is installed after the acceleration tubes and 2 x 45 degree bending magnets. Since the design of current undulator requires less than 25 MeV beam energy to obtain the radiation at THz region, the velocity bunching is reasonable for coherent radiation. We show the simulation results of a combination of velocity bunchings of the three tubes and the magnetic bunching at bending magnets, suitable for the coherent undulator radiation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK022

Export •

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