Related papers: Electron Cloud Density Measurements in Accelerator…
In the TE wave method, microwaves are coupled into the beam-pipe and the effect of the electron cloud on these microwaves is measured. An electron cloud (EC) density can then be calculated from this measurement. There are two analysis…
The measurement of electron cloud densities in particle accelerators using microwaves has proven to be an effective, non-invasive and inexpensive method. So far the experimental schemes have used continuous waves. This has either been in…
The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the…
The use of transverse electric (TE) waves has proved to be a powerful, noninvasive method for estimating the densities of electron clouds formed in particle accelerators. Results from the plasma simulation program VORPAL have been a useful…
The build up of electron clouds inside a particle accelerator vacuum chamber can produce strong transverse and longitudinal beam instabilities which in turn can lead to high levels of beam loss often requiring the accelerator to be run…
Electron cloud interaction with high energy positive beam are believed responsible for various undesirable effects such as vacuum degradation, collective beam instability and even beam loss in high power proton circular accelerator. An…
The Cornell Electron Storage Ring Test Accelerator experimental program includes investigations into electron cloud buildup, applying various mitigation techniques in custom vacuum chambers. Among these are two 1.1-m-long sections located…
In modern high-intensity accelerators, the circulating beam interacts in many ways with the vacuum beam pipe, causing a variety of different phenomena. Most of them have been discussed at length in other contributions to this CAS report. I…
Electron cloud effects have become one of the main performance limitations for circular particle accelerators operating with positively-charged beams. Among other machines worldwide, the CERN Super Proton Synchrotron (SPS), as well as the…
Electron microscopes have been improved to achieve ever smaller beam spots, a key parameter that determines the instrument's resolution. The techniques to measure the size of the beam, however, have not progressed to the same degree. There…
A novel kind of electron beam sustained discharge is presented in which a 12keV electron beam is combined with a 2.45GHz microwave power to excite argon gas at atmospheric pressure in a continuous mode of operation. Optical emission…
Starting from the separate codes BI-RME and ECLOUD or PyECLOUD, we are developing a novel joint simulation tool, which models the combined effect of a charged particle beam and of microwaves on an electron cloud. Possible applications…
The Electron Cloud, an undesirable physical phenomena in the accelerators, develops quickly as photons striking the vacuum chamberwall knock out electrons that are then accelerated by the beam, gain energy, and strike the chamber again,…
Electron clouds forming inside the beam vacuum chamber due to photoemission and secondary emission may limit the accelerator performance. Specifically, the electron clouds can blow up the vertical emittance of a positron beam, through a…
The Electron Cloud is an undesirable physical phenomenon which might produce single and multi-bunch instability, tune shift, increase of pressure ultimately limiting the performance of particle accelerators. We report our results on the…
As part of the CESR-TA program at Cornell, diagnostic devices to measure and quantify the electron cloud effect have been installed throughout the CESR ring. One such device is the Retarding Field Analyzer (RFA), which provides information…
In the Large Hadron Collider, electron clouds have been observed to cause slow beam degradation in the form of beam lifetime reduction and slow emittance growth. We present a method for the simulation of such slow effects with arbitrarily…
The electron cloud effect (ECE) causes beam instabilities in accelerator structures with intense positively charged bunched beams. Reduction of the secondary electron yield (SEY) of the beam pipe inner wall is effective in controlling cloud…
Electron cloud effects have recognized as as one of the most serious bottleneck for reaching design performances in presently running and proposed future storage rings. The analysis of these effects is usually performed with very time…
In this work, Rayleigh microwave scattering was utilized to measure the electron number density produced by nanosecond high voltage breakdown in air between two electrodes in a pin-to-pin configuration (peak voltage 26 kV and pulse duration…