Nakamura, T.

Paper	Title	Page
THB006	New Automatic Bunch Current Sensitive Fast Attenuator for RF Front-end of Bunch-by-Bunch Feedback System at SPring-8	659
	K. Kobayashi, T. Nakamura JASRI/SPring-8, Hyogo-ken
	We currently developing a new bunch current sensitive automatic attenuation system for the RF front-end of the bunch-by-bunch feedback system in the SPring-8 storage ring. It controls the attenuation of high current bunch signal to avoid the saturation of RF front-end and for equalization of the feedback gain for hybrid beam filling modes consist of few-mA singlet bunches and sub-mA bunch trains. We have already developed and installed a bunch current sensitive automatic attenuator with a simple mixer, a discriminator and FPGA based 1-turn delay with the attenuation level of 15 dB. However this attenuation level is not enough for hybrid filling modes with higher bunch current singlets and lower bunch current trains which are recently requested by users. To achieve more attenuation level and more flexible operation, we are now developing an attenuation system with a voltage variable attenuator controlled by a digital bunch current measurement device which is converted from a SPring-8 bunch-by-bunch feedback processor. This paper describes the new attenuation system and its test results.
THP072	Tune Tracking RFKO Bunch Purification with Bunch-by-bunch Feedback at SPring-8	803
	T. Nakamura, T. Aoki, K. Fukami, K. Kobayashi, M. Shoji, H. Yonehara JASRI/SPring-8, Hyogo-ken
	The drift of a betatron tune from a RFKO driving tune reduces the betatron amplitude excited by RFKO. For the booster synchrotron in SPring-8, such tune drift occurs at on-demand operation for the top-up mode injection. To overcome this drift, we are developing a tune tracking RFKO system for bunch purification at the booster. In this system, The betatron motion of the main bunch was excited by positive feedback with which the excited amplitude is much less sensitive to the tune shift. The system is based on SPring-8 FPGA based bunch-by-bunch feedback processor and the kick signal produced by the feedback processor was send to the feedback kicker and the RFKO system for the purification. We describe the system and report some beam test result.
WEP047	Upgrade of Readout System for Beam Position Monitors in the KEKB Beam Transport Line	495
	T. Aoyama, T. Nakamura, K. Yoshii MELCO SC, Tsukuba K. Furukawa, N. Iida, M. Satoh KEK, Ibaraki
	At the KEKB accelerator, electrons and positrons are injected from the LINAC to the storage ring through the beam transport (BT) line. LINAC had continuously injected each beam alternately every about a few minutes. In our linacs system, it is very important to switch acceleration devicesfrom electron mode to position and vica versa to keep high storage currents. To attain this, we have developed new readout system for the beam position monitors (BPMs) at the BT line, by which the fast monitoring is possible. For the old BPM system, it had been taken a few seconds to switch the beam modes and about one second to measure the beam positions. With the new system, measuring interval was achieved to be 20 msec, including switching time, and we demonstrated that new system contributed to stable beam operation. In this manuscript, we will report on a detail of the fast readout for the BT BPM system including its performance.
WEP074	Upgrading the Control System of the Movable Masks for KEKB	546
	T. Nakamura MELCO SC, Tsukuba K. Furukawa, T. T. Nakamura, J.-I. Odagiri KEK, Ibaraki
	The positron ring and the electron ring of KEKB have their own dedicated movable masks to cut off spent electrons/positrons near the beam orbit to reduce background in the detector. The stepping motor drivers of the movable masks were controlled by a Programable Logic Controller (PLC), which was supervised by a VME-based IOC. The IOC and the PLC was connected with each other by using GP-IB interface for the communication. Recently, however, the GP-IB connection came to be unstable causing communication errors between the IOC and the PLC. In order to solve the problem, a new type of IOC, which runs Linux on a CPU module of FA-M3 PLC, has been adopted. The CPU functions with standard I/O modules of FA-M3 on the PLC-bus. In this control system, we replaced an existing ladder CPU with the IOC and the ladder program with an EPICS sequencer program for the efficiency of software development and ease of maintenance. The new IOC has been successfully serving since it was put in operation in September 2008. In this paper, we describe the details of the new control system and its experiences up to the date.
WEP082	Embedded EPICS Controller for KEKB Pulsed Quadrupole Magnet Power Supply	558
	K. Mikawa, K. Furukawa, T. Mimashi, J.-I. Odagiri KEK, Ibaraki T. Nakamura MELCO SC, Tsukuba
	The pulsed quadrupole magnets have been installed in KEKB for the betatron tune adjustment. These magnets need to be controlled by the existing EPICS-based control system of the KEKB accelerator. While the control logic required for the operation of the magnet power supplies is rather conventional, it is preferable that we choose a front-end controller which allows us to develop and maintain the software in a highly efficient manner to cope with limited human resources. In order to satisfy this requirement, a new type of Input / Output Controller (IOC), which runs Linux on a CPU module of FA-M3 Programmable Logic Controller (PLC), has been adopted. The CPU functions with normal I/O modules of FA-M3 on the PLC-bus. We found that replacing ladder programs with EPICS sequencer makes the development and maintenance of the software for the IOC considerably efficient. This paper describes the details of the new IOC and its experiences in KEKB operation including long term stability.
THP052	New Event-based Control System for Simultaneous Top-up Operation at KEKB and PF	765
	K. Furukawa, T. T. Nakamura, M. Satoh, T. Suwada KEK, Ibaraki A. Kazakov Sokendai, Ibaraki T. Kudou, S. Kusano, T. Nakamura MELCO SC, Tsukuba
	The 8-GeV linac at KEK provides electrons and positrons to three ring accelerators of KEKB-HER, KEKB-LER and Photon Factory. Simultaneous top-up injections to those rings are carried for the ultimate experimental results at the both KEKB and PF facilities. An event-based fast control system was newly constructed overlapping the existent EPICS control system. The new system controls the distant equipment globally utilizing event modules from MRF and several other techniques. The event system enables fast controls from pico-second to milli-second range, and the conventional EPICS system covers slower controls. More than 100 parameters are driven globally by the event system every 20ms pulse in order to generate beams with three-times different energies and 100-times different charges. And more than 500 parameters are observed synchronously to ensure the beam operation. The system enables the future accelerator complex such as SuperKEKB as well. This paper describes the detailed design of the hardware and software structures, beam operation experiences, and possible extensions towards the future.
	Poster
THP100	Present Status and Upgrade of VME Computer in KEKB	874
	K. Yoshii, T. Nakamura MELCO SC, Tsukuba K. Furukawa, E. Kikutani, K. Mori, T. T. Nakamura KEK, Ibaraki
	We controlled main equipment of the accelerator used Epics based control system at KEKB. We had stabilized operation and development in basics as the upper limit,and Epics3.13, the CPU(PPC 6750) which we used from startup time now. However, the speedup of the network and the speedup of the CPU advanced, and the part that cannot correspond under the present conditions has become a problem gradually. Therefore, the necessity of Epics and CPU upgrade has gradually risen to us. We started developpment including upgrade CPU with PPC-MVME5500 and Epics with 3.14 form 2006 at KEKB. We have succeeded in the VME control by CPU PPC-MVME5500 which carried VXI, Trigger Reciver, PVME501, advme1522, Camac so far. We were realized fiveplaces of operation at present KEKB. In addition, the replacement is scheduled to be advanced as upgrade of CPU and Epics in the future based on the result. Here, this reports on the present status and upgrade of VME computer at KEKB.
THD005	Application of EPICS on F3RP61 to Accelerator Control	916
	J.-I. Odagiri, S. Araki, K. Furukawa, N. Kamikubota, A. Kiyomichi, K. Mikawa, S. Murasugi, H. Nakagawa, T. T. Nakamura, S. Yamada, N. Yamamoto KEK, Ibaraki K. Kameda, T. Natsui, H. Shiratsu Yokogawa, Tokyo M. Komiyama RIKEN Nishina Center, Wako S. Motohashi, M. Takagi Kanto Information Service (KIS), Accelerator Group, Ibaraki N. Nagura Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture T. Nakamura MELCO SC, Tsukuba A. Uchiyama SHI Accelerator Service ltd., Tokyo
	A new type of Input / Output Controller (IOC) has been developed based on F3RP61, a CPU module of FA-M3 Programmable Logic Controller (PLC). Since the CPU module runs Linux as its operating system, it takes no special effort to run EPICS IOC core program on the CPU module. With the aid of wide variety of I/O modules of FA-M3 PLC, the F3RP61-based IOC has various applications in accelerator control, such as magnet power supply control, monitoring interlock system, stepping motor control, data acquisition from beam monitors and so forth. The adoption of the new IOC makes the architecture of accelerator control systems simpler by unifying the two layers of front-end computers, i.e., the IOC layer and the PLC layer, into one layer. We found that the simplification of the control system architecture helps us to reduce the time and cost for the development and maintenance of the application software.