Matsubara, S.

Paper	Title	Page
TUC002	Recent Progress of RF and Timing System of XFEL/SPring-8	85
	H. Maesaka, T. Fukui, N. Hosoda, S. Matsubara, T. Ohshima, Y. Otake RIKEN/SPring-8, Hyogo M. Musha University of electro-communications, Tokyo K. Tamasaku RIKEN Spring-8 Harima, Hyogo
	For the XFEL facility at SPring-8, the acceleration rf is demanded to be transmitted for a long distance (~1km) and to be precisely controlled. The amplitude precision is 0.01 % and the phase precision is 0.1 degree of a 5712 MHz rf (50 fs timing accuracy). Therefore, we designed a stable optical timing and rf distribution system and a precise low-level rf control system. For the optical system, we employed a phase-stabilized optical fiber (PSOF) that has a very small temperature coefficient of 2 ppm/K. In addition, the fiber length is monitored by an optical interferometer and regulated by a variable delay line to reduce a remaining drift of PSOF. For the low-level rf system, we use an IQ modulator (demodulator) to generate (to detect) an acceleration rf signal. The baseband signals of the IQ modulator and demodulator are processed by 238MHz VME D/A and A/D converter boards, which have 14-bit and 12-bit resolutions, respectively. This system can manipulate the rf amplitude and phase with 0.01 % and 0.1 degree precision, respectively. These highly accurate instruments are very useful to other facilities.
	Slides
WEP023	Correction of Phase and Amplitude Error of RF Modulator and Demodulator	453
	T. Ohshima, N. Hosoda, H. Maesaka, S. Matsubara, Y. Otake RIKEN/SPring-8, Hyogo M. Yamaga JASRI/SPring-8, Hyogo-ken
	The XFEL/SPring-8 project is in progress. SASE in X-ray region requires a high peak current of 3 kA, which will be achieved with an extremely stable rf accelerating field. In most severe case, the acceptable error in an rf phase is extremely small, such as 0.01 degree in root mean square. To make a stable rf field, we developed a high-speed DAC/ADC and an IQ modulator/demodulator to control/detect the low level rf signals. Modules with high setting/detecting accuracy are one precondition to achieve good stability. But the developed modules could have offset and gain errors because of the requirement of the high-speed operation. So we made the calibration method using a network analyzer to correct the errors. By using this method we could reduce the phase error of the C-band IQ modulator from 0.5 degree p-p to 0.1 degree p-p, for example. In this paper the detail of the calibration method and its performance will be shown.
	Poster
WEP069	Beam Monitor System Controller for XFEL/SPring-8	534
	S. I. Inoue, H. Maesaka, S. Matsubara, Y. Otake RIKEN/SPring-8, Hyogo H. Ego, A. Yamashita, K. Yanagida JASRI/SPring-8, Hyogo-ken
	We have developed a controller for the beam monitor system of XFEL/SPring-8. The control items are the electronics of a beam position monitor (BPM) and a current transformer (CT), the actuator of a screen monitor (SCM) and the stepper motors of a SCM lens system and a beam collimator. To operate such complicated devices, we designed a control system based on a programmable logic controller (PLC). The PLC enables us to implement complex commands easily. For the communication between the PLC and other equipments, we employed FL-net (a protocol to communicate with computers) and DeviceNet (a connection with peripheral devices). Since FL-net is strongly supported by MADOCA, the official framework of SPring-8, we can easily integrate the PLC into the upper level system. DeviceNet is used in the electronics of the BPM and the CT and in the motor controllers of the SCM and the collimator. We newly developed a DeviceNet-based motor controller to satisfy our complicated requirements. Another multi-wire cable is equipped to manipulate the SCM actuator and so on. We tested the beam monitor controller at the SCSS test accelerator and confirmed that it worked well.