IPAC2011 - List of Authors (Kondoh, T.)

Paper	Title	Page
TUPC101	Generation of Multimode Quasi-monochromatic Terahertz	1248
	K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Generation of quasi-monochromatic terahertz (THz) using multimode Coherent Cherenkov Radiation (CCR) on the order of 0.1 THz was investigated. CCR was generated by a hollow dielectric tube covered by a metal and an electron bunch from a photocathode radio-frequency (RF) gun linac. The intensity and frequency of CCR were measured directly by a Michelson interferometer and a bolometer. The frequency spectra measured by the interferometer indicated sharp peaks close to frequencies of 0.09 THz and 0.14 THz, which corresponded to TM03 and TM04 modes, respectively, according to theoretical calculation for a tube with inner and outer radii of 5 mm and 7 mm. The maximum gain of TM03 mode due to the tube length was obtained as 1.5 dB/cm. The other higher modes, e. g. 0.36 THz (TM09) and 0.40 THz (TM010), were also observed from a 150 mm long tube at a bunch charge of 15 pC, which decreased space charge effect and the bunch length. Finally, a new method for bunch diagnostic based on multimode CCR was proposed. The bunch length was estimated to be 0.45 ps at a bunch charge of 5 pC with the intensity ratio of TM03 to TM09 mode.

Paper

Title

Page

Generation of Multimode Quasi-monochromatic Terahertz

1248

K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Generation of quasi-monochromatic terahertz (THz) using multimode Coherent Cherenkov Radiation (CCR) on the order of 0.1 THz was investigated. CCR was generated by a hollow dielectric tube covered by a metal and an electron bunch from a photocathode radio-frequency (RF) gun linac. The intensity and frequency of CCR were measured directly by a Michelson interferometer and a bolometer. The frequency spectra measured by the interferometer indicated sharp peaks close to frequencies of 0.09 THz and 0.14 THz, which corresponded to TM03 and TM04 modes, respectively, according to theoretical calculation for a tube with inner and outer radii of 5 mm and 7 mm. The maximum gain of TM03 mode due to the tube length was obtained as 1.5 dB/cm. The other higher modes, e. g. 0.36 THz (TM09) and 0.40 THz (TM010), were also observed from a 150 mm long tube at a bunch charge of 15 pC, which decreased space charge effect and the bunch length. Finally, a new method for bunch diagnostic based on multimode CCR was proposed. The bunch length was estimated to be 0.45 ps at a bunch charge of 5 pC with the intensity ratio of TM03 to TM09 mode.