Daisuke Ishida

The SINE WAVE ORCHESTRA stay

This is a report of creative and technical considerations in building a participatory sound performance The SINE WAVE ORCHESTRA stay. In this performance, the participants one by one leave their own sine wave in the performance space. These sine waves form a mutually interfering sound space while the sound field of a room changes during the performance.

Two-colored Laser Circulation System for Monochromatic Tunable Hard X-ray Source

A two-colored laser pulse circulation system for a monochromatic tunable hard X-ray source via laser electron Compton scattering is investigated. The demonstration system of the X-ray source is under construction at the University of Tokyo. It consists of the X-band (11.424 GHz) electron linear accelerator and two Nd: YAG laser systems. The main advantage of this system is a monochromatic tunable hard X-ray. It is calculated that the X-ray intensity will be about 108 photons/s. In order to enhance the X-ray intensity for medical applications such as dual energy X-ray CT, a two-colored laser pulse circulation system has been designed. The laser pulse circulation experiment without an electron beam has been carried out by using a Nd: YAG laser fundamental wave (50 mJ) and a second harmonics wave (25 mJ). The result shows that the X-ray intensity can be enhanced by a factor of 10 times higher (i.e., up to 109 photons/s). This work is a part of the JST (Japan Science and Technology Agency) project. The entire X-ray source system is a part of a larger national project on the development of an advanced compact medical accelerator sponsored by the NIRS (National Institute for Radiological Science). The University of Tokyo and KEK are responsible for the X-ray source.