Shoji, M.

Paper	Title	Page
TUOAFI03	Production of MeV Photons by the Laser Compton Scattering Using a Far Infrared Laser at SPring-8	961
	H. Ohkuma, M. Shoji, S. Suzuki, K. Tamura, T. Yorita JASRI/SPring-8, Hyogo-ken Y. Arimoto Osaka University, Osaka M. Fujiwara, K. Kawase RCNP, Osaka K. Nakayama, S. Okajima Chubu University, Kasugai, Aichi
	In order to produce MeV gamma-ray by the Laser Compton scattering (LCS), a high power optically pumped Far Infrared (FIR) laser has been developed at SPring-8. In the case of the SPring-8 storage ring, the momentum acceptance is so large (± 200 MeV) that the scattered electron is re-accelerated, then the stored beam is not lost by the LCS process. The beam diagnostics beamline is used to inject a FIR laser beam against 8-GeV stored electron beam and to extract MeV gamma-ray produced by LCS. The FIR laser system, gamma-ray production system, and measured gamma-ray spectrum will be presented. Future plans will also be introduced. In order to produce higher intense gamma-ray, we are constructing new gamma-ray production system at another beamline.
	Transparencies
TUPCH054	Upgrade of Signal Processing of the BPM System at the SPring-8 Storage Ring	1130
	T. Fujita, S. Sasaki, M. Shoji, T. Takashima JASRI/SPring-8, Hyogo-ken
	SPring-8 is a third generation synchrotron light source, which is operated stably with top-up mode and with optics of low emittance mode. Along with stabilization of electron beam orbit in the ring, upgrading of the BPM system has also been required. We have developed a new signal processing circuit for COD measurement with a target of a few microns of position resolution at 1 kHz band-width and a few hundreds per second to take beam position of all BPMs. In the new circuit, a multiplexing method is employed and the IF frequency is directory detected with a 2MSPS 16-bit ADC. The digitized signal is processed with DSP to obtain beam position. Analog components of the circuit are equipped in a temperature controlled cabinet in order not to be affected by fluctuation of ambient temperature. In this paper we report schematics and performance of the new circuit, e.g., dependence of position resolution on measurement band-width and long time stability, etc. In addition, we briefly describe possibility of fast orbit measurement as a further application of the circuit.