| Paper | Title | Page |
|---|---|---|
| MOPAN030 | Analysis of Transverse Beam Oscillation at Photon Factory | 221 |
|
||
| FPGA based bunch by bunch feedback system to cure the transverse instabilities has been in operation stably since Oct. 2005. Specification and performance of the system will be introduced, transient measurement has been done to analyze the instability modes, which helps to understand the instability sources. Bunch by bunch beam oscillation, together with the digital turn-by-turn beam position measurement, injection oscillation damping is recorded and analyzed, transverse beam oscillation with and without the bunch by bunch feedback system will be shown in this paper. Precise tune measurement during this period will be presented. Turn by turn phase space monitor is also available with the data, from which the nonlinear beam dynamics can be revealed. | ||
| MOPAN036 | Longitudinal Feedback System for the Photon Factory | 233 |
|
||
| In the KEK-PF, longitudinal coupled-bunch instabilities are suppressed by means of the RF phase-modulation technique during the users operation. This method is very effective not only to suppress the instabilities but also to enlarge the beam lifetime. Together with the feasibility study for top-up operation, bunch-by-bunch feedback system have been developed. A two-port longitudinal kicker based on dafne-type cavity were designed and installed in the storage ring in the summer of 2006. FPGA-based signal processing part is under development based on the KEKB design. As an preliminary test of the longitudinal kicker, a simple mode-feedback system which suppress a specific coupled-bunch mode were tested successfully. | ||
| MOPAS067 | Control and Measurements of Longitudinal Coupled-bunch Instabilities in the ATF Damping Ring | 584 |
|
||
|
Funding: Work supported by U. S. Department of Energy contract DE-AC02-76SF00515 and by the US-Japan collaboration in High Energy Physics Damping ring at the Accelerator Test Facility (ATF) is a storage ring with 714 MHz RF frequency and harmonic number of 330. The ring is used in both single and multibunch regimes. In both cases significant longitudinal dipole motion has been observed in the ring. A prototype longitudinal feedback channel using a Gproto baseband processing channel and a set of horizontal striplines has been constructed for the machine. The prototype allowed both suppression of the longitudinal motion and studies of the motion sources. In this paper we present the results of these studies including measurements of steady-state oscillation amplitudes, eigenmodal patterns, and growth and damping rates. Using measured growth rates we estimate the driving impedances. We also present the effect of the longitudinal stabilization on the energy spread of the extracted beam as documented by a screen monitor. |
||
| TUPMN045 | PF-Ring and PF-AR Operational Status | 1019 |
|
||
| In KEK, we have two synchrotron light sources which were constructed in the early 1980s. One is the Photon Factory storage ring (PF-ring) and the other is the Photon Factory advanced ring (PF-AR). The PF-ring is usually operated at 2.5 GeV and sometimes ramped up to 3.0 GeV to provide photons with the energy from VUV to hard X-ray region. The PF-AR is mostly operated in a single-bunch mode of 6.5 GeV to provide pulsed hard X-rays. Operational performances of them have been upgraded through several reinforcements. After the reconstruction of the PF-ring straight sections from March to September 2005, two short-gap undulators were newly installed. They allow us to produce higher brilliant hard X-rays even at the energy of 2.5 GeV. At present we are going to prepare a top-up operation for the PF-ring. In the PF-AR, new tandem undulators have been operated in one straight section since September 2006 to generate much stronger pulsed hard X-rays for the sub-ns resolved X-ray diffraction experiments. In this conference, we report operational status of the PF-ring and the PF-AR including other machine developments. |