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014801-1 Present and future accelerators’ performances may be limited by the electron cloud (EC) effect. The EC formation and evolution are determined by the wall-surface properties of the accelerator vacuum chamber. We present measurements of the total secondary electron yield (SEY) and the related energy distribution curves of the secondary electrons as a(More)
This note describes the program HEADTAIL for the simulation of transverse and longitudinal single bunch phenomena, with special emphasis on the instability and emittance growth induced by an electron cloud. All input parameters as well as the standard output files are described here. The note is intended to provide potential users with the guidelines for(More)
This note describes the use of the program ECloud for the simulation of the electron cloud build up, which occurs due to photoemission, ionization, and secondary emission inside an accelerator beam pipe during the passage of a narrowly spaced proton or positron bunch train. All input parameters as well as the standard output files are explained. The goal of(More)
The term ‘electron cloud’ refers to an accumulation of electrons inside an accelerator beam pipe which is sufficiently strong to affect the accelerator operation, e.g., by causing beam loss, emittance growth, increase in the vacuum pressure, or degradation of the beam diagnostics. Primary electrons are generated by a number of processes. Their number can be(More)
The Cornell Electron Storage Ring Test Accelerator (CesrTA) 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 symmetrically in the east and west arc regions. These chambers are equipped with pickup detectors shielded against the(More)
Since June 2011 the rapid increase of the luminosity performance of the LHC has come at the expense of both increased temperature and pressure of specific, nearbeam, LHC equipment. In some cases, this beam induced heating has caused delays while equipment cool-down, beam dumps and even degradation of some devices. This contribution gathers the observations(More)
-Visualization is a key aspect in geometric modeling. Since the processing required for realistic display is often considerable, the design of parallel visualization algorithms is a trying task. In this paper a new parallel approach to Hidden Surface Removal, called Parallel Depth-Merge (PDM), is proposed. PDM, intrinsically parallel, couples any already(More)
The electron cloud (EC) can be formed in the beam pipe of a circular accelerator if the secondary emission yield (SEY) of the inner surface is larger than 1, and it can detrimentally affect the circulating beam. Understanding the underlying physics and defining the scaling laws of this effect is indispensable to steer the upgrade plans of the existing(More)
A quasi-stationary electron cloud can drive single-bunch instabilities on a circulating beam through a head-tail coupling mechanism. The oscillation frequency of the electrons in the transverse field of the bunch, and how it can be expressed as a function of the bunch properties, is essential for the understanding of this instability. The process of the(More)