A5053763265- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- Distributed and Parallel Computing Systems
- Magnetic confinement fusion research
- Advanced Data Storage Technologies
- Soil Moisture and Remote Sensing
- Engineering Applied Research
- Particle physics theoretical and experimental studies
- Semiconductor Lasers and Optical Devices
- Precipitation Measurement and Analysis
- Energy Harvesting in Wireless Networks
- Nuclear reactor physics and engineering
- Advanced Frequency and Time Standards
- Muon and positron interactions and applications
- Real-time simulation and control systems
- Numerical methods for differential equations
- Advancements in PLL and VCO Technologies
- Photocathodes and Microchannel Plates
- Experimental Learning in Engineering
- Advanced Electrical Measurement Techniques
- Advanced X-ray Imaging Techniques
- Adaptive optics and wavefront sensing
Cytel (United States)
2008-2020
Institute of High Energy Physics
2018
SLAC National Accelerator Laboratory
1999-2014
Stanford University
2000-2014
Menlo School
2003-2009
Linac Coherent Light Source
2006-2009
Stanford Synchrotron Radiation Lightsource
1998-2007
Lawrence Berkeley National Laboratory
2000-2002
European Science Foundation
2002
College of Staten Island
2002
The electron-positron collider DAPhiNE, the Italian Phi factory, has been recently upgraded in order to implement an innovative collision scheme based on large crossing angle, small beam sizes at point, and compensation of beam-beam interaction by means sextupole pairs creating a "crab-waist" configuration region. Experimental tests novel exhibited increase factor 3 peak luminosity with respect performances reached before upgrade. In this Letter we present new scheme, discuss its advantages,...
The DAΦNE collider has been recently upgraded in order to implement a new collision scheme based on large Piwinski angle and cancellation of the synchro-betatron resonances by means electromagnetic sextupoles (Crab-Waist compensation). novel approach proved be effective improving beam-beam interaction luminosity. results measurements taken during commissioning as well perspectives for SIDDHARTA run are presented discussed.
The design of a 250 MHz bandwidth, bunch-by-bunch feedback system for controlling transverse coupled-bunch instabilities in the PEP-II Asymmetric B-Factory is described. Relevant parameters and specifications are discussed along with key components. In particular, front-end receivers, baseband processing electronics, kickers presented some detail.
As circular accelerators move towards larger numbers of bunches and higher beam currents, the task diagnosing curing coupled-bunch instabilities becomes ever harder. This paper describes use phase space tracking, i.e. reconstruction bunch trajectories, as a comprehensive instability diagnostic. A new cure is also presented, based on recent insights into dynamics unevenly-filled rings. Data shown from PEP-II ALS, where "optimally shaped" uneven fills have yielded significant increases in thresholds.
A modular programmable longitudinal feedback system has been developed as a component of the PEP-II R+D program. This is based on family VME and VXI packaged signal processing functions which implement general purpose digital controller for accelerators with bunch spacings 2 ns. complete prototype configured installed use at LBL Advanced Light Source. The configuration used tests ALS described results are presented showing action system. Open closed loop detection calculation signals from...
A time domain dynamic modeling and simulation tool for beam-cavity interactions in the Low Energy Ring (LER) High (HER) at Positron-Electron Project (PEP-II) is presented. Dynamic results PEP-II are compared to measurements of actual machine. The motivation this explore stability margins performance limits radio-frequency (RF) systems future higher currents upgraded RF configurations. It also serves as a test bed new control algorithms can define ultimate low-level (LLRF) architecture....
The Positron-Electron Project II (PEP-II) B Factory collider ended the final phase of operation at nearly twice design current and 4X luminosity. In ultimate state, eight 1.2 MW radio-frequency (rf) klystrons 12 accelerating cavities were added beyond original implementation, two storage rings operating with longitudinal instability growth rates roughly 5X in excess estimates. From initial commissioning there has been continual adaptation low level rf (LLRF) control strategies, configuration...
A dynamics simulation model is used to estimate limits of performance the positron-electron project (PEP-II). The captures and technical limitations low level radio frequency (LLRF) system, high-power rf components, low-order mode coupled-bunch longitudinal beam dynamics. Simulation results showing effect nonlinearities on LLRF loops, studies effectiveness component upgrades are reported, as well a comparison these with PEP-II measurements. These have led estimation determining factors in...
The operation of a longitudinal multibunch damping system using digital signal processing (DSP) techniques is shown via measurements from the Lawrence Berkeley Laboratory (LBL) Advanced Light Source (ALS). feedback (developed for use by PEP-II, ALS, and DAɸNE) uses parallel array processors to implement bunch-by-bunch sampling rates up 500 MHz. programmable DSP allows control as well accelerator diagnostics. A diagnostic technique illustrated which excite then damp beam. resulting 12-ms time...
We describe an instability diagnostic that exploits the information contained in angular evolution of coupled-bunch oscillations phase space. In addition to enabling measurement coherent tunes and bunch with accuracy a few hertz, space tracking allows new kinds comparisons between theory experiment. Phase bunches participating low-threshold vertical high energy ring Stanford Linear Accelerator Center B factory (PEP-II) is used distinguish fast beam-ion conventional instabilities. Tracking...
A new digital three dimensional fast bunch-by-bunch feedback system has been installed and commissioned at ANKA. Immediate improvements to stored current lifetime were achieved for normal user operation. For this, the be running during injection energy ramp 2.5 GeV. Additionally, was also incorporated into diagnostic tool-set ANKA opened up possibilities of automated continuous measurement certain beam parameters. The can operate in different modes such as low alpha operation mode, which...
The PEP-II/ALS/DA/spl Phi/NE feedback systems are complex implemented using analog, digital and microwave circuits. VXI hardware implementation for the front-end back-end analog processing modules is presented. module produces a baseband beam phase signal from pickups tone burst generator. generates an AM/QPSK modulated correction computed in processor. These components packages that allow wide spectrum of system functions including 120 MHz bandwidth rms detector, reference servo, woofer...
A longitudinal quadrupole ($q$-pole) instability was limiting the maximum stable current in DA$\ensuremath{\Phi}$NE ${e}^{\ensuremath{-}}$ ring at a level of $\ensuremath{\sim}700--800\text{ }\text{ }\mathrm{mA}$. In order to investigate phenomenon, threshold has been measured as function various machine parameters radio frequency voltage (${V}_{\mathrm{rf}}$), momentum compaction (${\ensuremath{\alpha}}_{c}$), number bunches, fill pattern, etc. An unexpected interaction with feedback...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation D. Teytelman, J. Fox, H. Hindi, C. Limborg, I. Linscott, S. Prabhakar, Sebek, A. Young, Drago, M. Serio, W. Bȧrry, G. Stover; Beam diagnostics based on time-domain bunch-by-bunch data. AIP Conference Proceedings 10 December 1998; 451 (1): 222–228. https://doi.org/10.1063/1.57048 Download citation file: Ris...
The DSP-based bunch-by-bunch feedback system installed in the PEP-II high-energy ring (HER) has been used to damp instabilities induced by unwanted higher-order modes (HOMs) at beam currents up 605 mA during commissioning. Beam pseudospectra calculated from data indicate presence of coupled-bunch that coincide with a previously observed cavity mode (0-M-2). Bunch current and synchronous phase measurements are also extracted data. These reveal impedance seen revolution harmonics. peak 3×frev...