Control of Multibunch Longitudinal Instabilities and Beam Diagnostics Using a DSP-based Feedback System
Abstract
A bunch-by-bunch longitudinal feedback system has been designed and built to control coupled-bunch instabilities in the PEP-II machine. A prototype system has been installed at the Advanced Light Source at LBNL. Programmable DSPs allow longitudinal feedback processing in conjunction with data acquisition or instrumentation algorithms. Here the authors describe techniques developed for different beam and system diagnostics, such as measurements of the modal growth and damping rates and measurements of the bunch-by-bunch currents. Results from the Advanced Light Source are presented to illustrate these techniques.
- Authors:
- Publication Date:
- Research Org.:
- Stanford Linear Accelerator Center, Menlo Park, CA (US)
- Sponsoring Org.:
- USDOE Office of Energy Research (ER) (US)
- OSTI Identifier:
- 763752
- Report Number(s):
- SLAC-PUB-8415
TRN: US0004791
- DOE Contract Number:
- AC03-76SF00515
- Resource Type:
- Technical Report
- Resource Relation:
- Other Information: PBD: 30 Mar 2000
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 43 PARTICLE ACCELERATORS; BEAM MONITORS; DESIGN; BEAM BUNCHERS; PEP STORAGE RINGS; ADVANCED LIGHT SOURCE; BEAM DYNAMICS
Citation Formats
Teytelman, Dmitry. Control of Multibunch Longitudinal Instabilities and Beam Diagnostics Using a DSP-based Feedback System. United States: N. p., 2000.
Web. doi:10.2172/763752.
Teytelman, Dmitry. Control of Multibunch Longitudinal Instabilities and Beam Diagnostics Using a DSP-based Feedback System. United States. doi:10.2172/763752.
Teytelman, Dmitry. Thu .
"Control of Multibunch Longitudinal Instabilities and Beam Diagnostics Using a DSP-based Feedback System". United States.
doi:10.2172/763752. https://www.osti.gov/servlets/purl/763752.
@article{osti_763752,
title = {Control of Multibunch Longitudinal Instabilities and Beam Diagnostics Using a DSP-based Feedback System},
author = {Teytelman, Dmitry},
abstractNote = {A bunch-by-bunch longitudinal feedback system has been designed and built to control coupled-bunch instabilities in the PEP-II machine. A prototype system has been installed at the Advanced Light Source at LBNL. Programmable DSPs allow longitudinal feedback processing in conjunction with data acquisition or instrumentation algorithms. Here the authors describe techniques developed for different beam and system diagnostics, such as measurements of the modal growth and damping rates and measurements of the bunch-by-bunch currents. Results from the Advanced Light Source are presented to illustrate these techniques.},
doi = {10.2172/763752},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Mar 30 00:00:00 EST 2000},
month = {Thu Mar 30 00:00:00 EST 2000}
}
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.
-
Multi-Bunch Longitudinal Dynamics and Diagnostics via a Digital Feedback System at PEP-II, DAFNE, ALS and SPEAR
A bunch-by-bunch longitudinal feedback system based on a programmable DSP architecture is used to study coupled-bunch motion and its sources. Experimental results are presented from PEP-II, DA{Phi}NE, ALS and SPEAR to highlight the operational experience from 4 installations, plus show novel accelerator diagnostics possible with the digital processing system. Modal growth and damping rates are measured via short (20 ms) transient recordings for unstable and stable coupled-bunch modes. Data from steady-state measurements are used to identify unstable modes and noise-driven beam motion. A novel impedance measurement technique is presented which reveals the longitudinal impedance as a function of frequency. Thismore » -
VXI based multibunch detector and QPSK modulator for the PEP-II/ALS/DA{Phi}NE longitudinal feedback system
The PEP-II/ALS/DA{Phi}NE feedback systems are complex systems implemented using analog, digital and microwave circuits. The VXI hardware implementation for the Front-end and Back-end analog processing modules is presented. The Front-end module produces a baseband beam phase signal from pickups using a microwave tone burst generator. The Back-end VXI module generates an AM/QPSK modulated signal from a baseband correction signal computed in a digital signal processor. These components are implemented in VXI packages that allow a wide spectrum of system functions including a 120 MHz bandwidth rms detector, reference phase servo, woofer link to the RF control system, standard VXI status/control,more » -
Analysis of DSP-based longitudinal feedback system: Trials at SPEAR and ALS
Recently a single-channel prototype of the proposed PEP-II longitudinal feedback system was successfully demonstrated at SPEAR and ALS on single-bunch beams. The phase oscillations are detected via a wide-band pick up. The feedback signal is then computed using a digital signal processor (DSP) and applied to the beam by phase modulating the rf. We analyze results in the frequency- and the time-domain and show how the closed-loop transfer functions can be obtained rigorously by proper modeling of the various components of this hybrid continuous/digital system. The technique of downsampling was used in the experiments to reduce the number of computationsmore » -
Programmable DSP-Based Multi-Bunch Feedback - Operating Experience from Six Installations
A longitudinal instability control system, originally developed for the PEP-II, DAPHNE and ALS machines has in the last two years been commissioned for use at the PLS and BESSY-II light sources. All of the installations are running identical hardware and use a common software distribution package. This common structure is beneficial in sharing expertise among the labs, and allows rapid commissioning of each new installation based on well-understood diagnostic and operational techniques. While the installations share the common instability control system, there are significant differences in machine dynamics between the various colliders and light sources. These differences require careful specificationmore »