SPS ECLOUD INSTABILITIES - ANALYSIS OF MACHINE STUDIES AND IMPLICATIONS FOR ECLOUD FEEDBACK [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 621.3675 Electrical, magnetic, optical, communications, computer engineering; electronics, lighting
• Thông tin xuất bản: Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2010
• Mô tả vật lý: Size: 3 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 262440
• Chủ đề: 1. 60; 2. Accelerators; 3. Beam bunching; 4. Beam dynamics; 5. Comparative evaluations; 6. Feedback; 7. Instability; 8. Simulation; 9. Trajectories

Tóm tắt

The SPS at high intensities exhibits transverse single-bunch instabilities with signatures consistent with an Ecloud driven instability. They present recent MD data from the SPS, details of the instrument technique and spectral analysis methods which help reveal complex vertical motion that develops within a subset of the injected bunch trains. The beam motion is detected via wideband exponential taper striplines and delta-sigma hybrids. The raw sum and difference data is sampled at 50 GHz with 1.8 GHz bandwidth. sliding window FFT techniques and RMS motion techniques show the development of large vertical tune shifts on portions of the bunch of nearly 0.025 from the base tune of 0.185. Results are presented via spectrograms and bunch slice trajectories to illustrate development of the unstable beam and time scale of development along the injected bunch train. The study shows that the growing unstable motion occupies a very broad frequency band of 1.2 GHz. These measurements are compared to numerical simulation results, and the system parameter implications for an Ecloud feedback system are outlined.