Impedance of the PEP - II DIP Screen
نویسنده
چکیده
The vacuum chamber of a storage ring normally consists of periodically spaced pumping slots. The longitudinal impedance of slots are analyzed in this paper. It is found that although the broad-band impedance is tolerable, the narrow-band impedance, as a consequence of the periodicity of the slots, may exceed the stability limit given by natural damping with no feedback system on. Based on this analysis, the PEP-II distributed-ionpump (DIP) screen uses long grooves with hidden holes cut halfway to reduce both the broad-band and narrow-band impedances. Presented at the Workshop on Collective E ects and Impedance for B-Factories, Tsukuba, Japan, June 12-17, 1995 Work supported by Department of Energy, contract DE-AC03-76SF00515.
منابع مشابه
Analysis of the Wake Field Effects in the Pep-ii Slac B- Factory*
We present the history and analysis of different wake field effects throughout the operational life of the PEP-II SLAC B-factory. Although the impedance of the high and low energy rings is small, the intense high current beams generated a lot of power. The effects from these wake fields are: heating and damage of vacuum beam chamber elements like RF seals, vacuum valves , shielded bellows, BPM ...
متن کاملRF Feedback Analysis for Four Cavities per Klystron in PEP - II
Lattice changes in the PEP-II high energy ring have made the concept of driving four cavities with a single klystron an attractive option. This paper examines the topology from a RF feedback point of view. Sources of error are identified and their magnitudes are estimated. The effect on the performance of the longitudinal impedance reducing feedback loops is calculated using control theory and ...
متن کاملUpdated Impedance Estimate of the Pep-ii Rf Cavity
This paper presents an updated estimate of the higher-order mode impedance spectrum of the RF cavities for the PEP-II B-factory. The cavity is designed for continuous operation at 476 MHz with up to 150 kW wall dissipation and heavy beam loading. To reduce the growth rates of coupled-bunch instabilities the cavity higher-order modes are damped by three rectangular waveguides and broad-band load...
متن کاملAnti-corrosive Properties of CeO2 Conversion Coatings on Aluminum Alloy 2024 Prepared by Dip Immersion Method
As an alternative to chromate conversion coatings, rare-earth coatings especially cerium, because of the low toxicity, have attracted considerable attention. Using dip immersion method, cerium-based conversion coating was deposited on aluminum 2024. Corrosion resistance was studied in 3.5 wt.% NaCl solution using potentiodynamic polarization, electrochemical impedance spectroscopy, and surface ...
متن کاملCommissioning Experience from PEP-II HER Longitudinal Feedback
The DSP-based bunch-by-bunch feedback system installed in the PEPII high-energy ring (HER) has been used to damp instabilities induced by unwanted higher-order modes (HOMs) at beam currents up to 605 mA during commissioning. Beam pseudospectra calculated from feedback system data indicate the presence of coupled-bunch modes that coincide with a previously observed cavity mode (0-M-2). Bunch cur...
متن کامل