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制度:新 ; 文部省報告番号:甲1928号 ; 学位の種類:博士(工学) ; 授与年月日:2004/3/24 ; 早大学位記番号:新3814

We have been developing an Energy-Chirping-Cell attached RF electron gun (ECC-RF-Gun) for generating ultra-short electron bunches. ECC-RF-Gun has extra cell at the end of gun cavity in order to chirp the bunch energy. Such a bunch can be compressed by the velocity difference though the drift space. We have already installed it to our accelerator system and successfully observed a coherent synchrotron/transition radiation at 0.3THz. It is clear that the bunch length was short enough to generate 0.3THz, which corresponds to less than 500fs bunch length was achieved if we assume the gaussian shape. In this conference, the principle of ECC-RF-Gun, the recent results of bunch length measurement and future prospective will be presented., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

Advanced quantum radiation sources such as a laser Compton scattering X-ray source and a coherent THz radiation source have been developed based on an S-band compact electron linac at AIST in Japan. The laser Compton scattering X-ray source using a TW Ti:Sa laser can generate a hard X-ray pulse which has variable energy of 12 keV - 40 keV with narrow bandwidth by changing electron energy and collision angle for medical and biological applications. The coherent THz radiation source based on the electron linac has been also developed instead of a conventional laser based THz source. The designed THz pulse has high peak power more than 1 kW in frequency range between 0.1 - 2 THz. The THz pulse will be generated with coherent radiation such as synchrotron radiation and transition radiation using an ultra-short electron bunch with bunch length of less than 0.5 ps (rms). The coherent synchrotron radiation in the THz region has been already generated and it will be applied to the THz time domain spectroscopy (TDS). In this work shop, we will report present status of our advanced quantum radiation sources., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

A C-band RF gun for compact radiation sources such as a high energy x-ray and a terahertz radiation is developed at AIST, which is designed to work at the frequency of 5.3 GHz*. A coniferous-tree-type carbon nanostructure (CCNS) is used for a field emission cathode in the C-band RF gun. A graphene sheet composed of carbon has a coniferous form, and the tip has a nanometer-size tubular structure that becomes thicker on the substrate side**. Owing to this configuration, the CCNS has a large field enhancement factor, and is considered to be more stable in high electric fields than Carbon nanotubes. We have fabricated the C-band RF gun of the single cell cavity. Emission current depending on the electric field strength on the CCNS cathode surface was measured. When the electric field strength was 30 MV/m, the total charge per a macro pulse was 30 nC. After applying a stronger electric field, a decline of the field enhancement factor was observed. We will present the experimental result of the field emission measurement of the CCNS and the simulation result of a beam trajectory using a C-band RF gun of a multi cell cavity., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA