192 research outputs found
The Quadratic Coefficient of the Electron Cloud Mapping
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
analytical study of the electron dynamics.Comment: 5 pages, 7 figures, presented at ECLOUD12: Joint
INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects, La Biodola, Isola
d Elba, Italy, 5-9 June 201
Maps for Electron Clouds: Application to LHC Conditioning
In this communication we present a generalization of the map formalism,
introduced in [1] and [2], to the analysis of electron flux at the chamber wall
with particular reference to the exploration of LHC conditioning scenarios.Comment: 3 pages, 4 figure
A Formula of the Electron Cloud Linear Map Coefficient in a Strong Dipole
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 consuming simulation codes. An alternative analytic approach, based
on a cubic map model for the bunch-to-bunch evolution of the electron cloud
density, could be useful to determine regions in parameters space compatible
with safe machine operations. In this communication we derive a simple
approximate formula relating the linear coefficient in the electron cloud
density map to the parameters relevant for the electron cloud evolution with
particular reference to the LHC dipoles.Comment: 3 pages, 5 figures. Proceeding of IPAC 201
Maps for electron clouds: application to LHC
In this communication we show that the cubic map formalism introduced in [1] to model electron cloud in RHIC is also reliable in the range of typical LHC parameters
Maps for electron cloud density in Large Hadron Collider dipoles
The generation of a quasistationary electron cloud inside the beam pipe through beam-induced multipacting processes has become an area of intensive study. The analyses performed so far have been based on heavy computer simulations taking into account photoelectron production, secondary emission, electron dynamics, and space charge effects, providing a detailed description of the electron-cloud evolution. Iriso and Peggs [U. Iriso and S. Peggs, Phys. Rev. ST Accel. Beams 8, 024403 (2005)] have shown that, for the typical parameters of RHIC, the bunch-to-bunch evolution of the average electron-cloud density at a point can be represented by a cubic map. Simulations based on this map formalism are orders of magnitude faster compared to those based on standard particle tracking codes. In this communication we show that the map formalism is also applicable to the case of the Large Hadron Collider (LHC), and that, in particular, it reproduces the average electron-cloud densities computed using a reference code to within âŒ15% for general LHC bunch filling patterns. We also illustrate the dependence of the polynomial map coefficients on the physical parameters affecting the electron cloud (secondary emission yield, bunch charge, bunch spacing, etc.)
A Nearly Minimum Redundant Correlator Interpolation Formula for Gravitational Wave Chirp Detection
An absolute lower bound on the number of templates needed to keep the fitting factor above a prescribed minimal value in correlator bank detection of (newtonian) gravitational wave chirps from unknown inspiraling compact binary sources is derived, resorting to the theory of quasi-bandlimited functions in the norm. An explicit nearly-minimum redundant cardinal-interpolation formula for the (reduced, noncoherent) correlator is introduced. Its computational burden and statistical properties are compared to those of the plain lattice of (reduced, noncoherent) correlators, for the same . Extension to post-newtonian models is outlined
Simulations and Studies of Electron Beam Dynamics under Compton Back-scattering for the Compact X-ray Source ThomX
MOPWO004 - ISBN 978-3-95450-122-9International audienceIn this article are presented beam dynamics investiga- tions of a relativistic electron bunch in the compact storage ring ThomX (50 MeV), which is under construction at LAL to produce hard X-ray using Compton Back-Scattering (CBS). The effect of CBS has been implemented in a 6D tracking code. In addition to CBS, the influence of lattice non linearities and various collective effects on the flux of scattered Compton photons is investigated
Erratum: Search for gravitational-wave bursts in LIGO data from the fourth science run (Classical and Quatnum Gravity (2007) 24 (5343-5369))
Optimum Placement of Post-1PN GW Chirp Templates Made Simple at any Match Level via Tanaka-Tagoshi Coordinates
A simple recipe is given for constructing a maximally sparse regular lattice
of spin-free post-1PN gravitational wave chirp templates subject to a given
minimal match constraint, using Tanaka-Tagoshi coordinates.Comment: submitted to Phys. Rev.
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