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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, ion-ization, 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(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)
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)
1.1.1 Introduction For linear accelerators, a single bunch instability of a positron bunch due to electrons created by ionization of the residual gas was discussed in Ref. [1], where a coherent oscillation of both electrons and positrons grows from any small initial perturbation of the bunch distribution, e.g. from the statistical fluctuations due to the(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)
Measurements of transverse oscillations of single bunches of protons in the SPS at 26 GeV are described. They are used to monitor the transverse impedance of the SPS. There has been a major effort to reduce the SPS impedance in the last winter shutdown, by shielding of most pumping ports and removal of obsolete (lepton) components. In fact, a significant(More)
The CLIC Damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm nor-malised at 2.86 GeV, with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference , lattice, momentum compaction,(More)