256 research outputs found
An experimentally robust technique for halo measurement using the IPM at the Fermilab Booster
We propose a model-independent quantity, , to characterize non-Gaussian
tails in beam profiles observed with the Fermilab Booster Ion Profile Monitor.
This quantity can be considered a measure of beam halo in the Booster. We use
beam dynamics and detector simulations to demonstrate that is superior to
kurtosis as an experimental measurement of beam halo when realistic beam
shapes, detector effects and uncertainties are taken into account. We include
the rationale and method of calculation for in addition to results of the
experimental studies in the Booster where we show that is a useful halo
discriminator
Fully 3D Multiple Beam Dynamics Processes Simulation for the Tevatron
We present validation and results from a simulation of the Fermilab Tevatron
including multiple beam dynamics effects. The essential features of the
simulation include a fully 3D strong-strong beam-beam particle-in-cell Poisson
solver, interactions among multiple bunches and both head-on and long-range
beam-beam collisions, coupled linear optics and helical trajectory consistent
with beam orbit measurements, chromaticity and resistive wall impedance. We
validate individual physical processes against measured data where possible,
and analytic calculations elsewhere. Finally, we present simulations of the
effects of increasing beam intensity with single and multiple bunches, and
study the combined effect of long-range beam-beam interactions and transverse
impedance. The results of the simulations were successfully used in Tevatron
operations to support a change of chromaticity during the transition to
collider mode optics, leading to a factor of two decrease in proton losses, and
thus improved reliability of collider operations.Comment: 29 pages, 19 figures, submitted to Phys. Rev. ST Accel. Beam
A Parallel General Purpose Multi-Objective Optimization Framework, with Application to Beam Dynamics
Particle accelerators are invaluable tools for research in the basic and
applied sciences, in fields such as materials science, chemistry, the
biosciences, particle physics, nuclear physics and medicine. The design,
commissioning, and operation of accelerator facilities is a non-trivial task,
due to the large number of control parameters and the complex interplay of
several conflicting design goals. We propose to tackle this problem by means of
multi-objective optimization algorithms which also facilitate a parallel
deployment. In order to compute solutions in a meaningful time frame a fast and
scalable software framework is required. In this paper, we present the
implementation of such a general-purpose framework for simulation-based
multi-objective optimization methods that allows the automatic investigation of
optimal sets of machine parameters. The implementation is based on a
master/slave paradigm, employing several masters that govern a set of slaves
executing simulations and performing optimization tasks. Using evolutionary
algorithms as the optimizer and OPAL as the forward solver, validation
experiments and results of multi-objective optimization problems in the domain
of beam dynamics are presented. The high charge beam line at the Argonne
Wakefield Accelerator Facility was used as the beam dynamics model. The 3D beam
size, transverse momentum, and energy spread were optimized
SYNERGIA: A MODERN TOOL FOR ACCELERATOR PHYSICS SIMULATION
Abstract High precision modeling of space-charge effects, together with accurate treatment of single-particle dynamics, is essential for designing future accelerators as well as optimizing the performance of existing machines. Synergia is a high-fidelity parallel beam dynamics simulation package with fully three dimensional space-charge capabilities and a higher order optics implementation. We describe the computational techniques, the advanced human interface, and the parallel performance obtained using large numbers of macroparticles
Strange Quark PDFs and Implications for Drell-Yan Boson Production at the LHC
Global analyses of Parton Distribution Functions (PDFs) have provided
incisive constraints on the up and down quark components of the proton, but
constraining the other flavor degrees of freedom is more challenging.
Higher-order theory predictions and new data sets have contributed to recent
improvements. Despite these efforts, the strange quark PDF has a sizable
uncertainty, particularly in the small x region. We examine the constraints
from experiment and theory, and investigate the impact of this uncertainty on
LHC observables. In particular, we study W/Z production to see how the s-quark
uncertainty propagates to these observables, and examine the extent to which
precise measurements at the LHC can provide additional information on the
proton flavor structure.Comment: 14 pages, 11 figures, added reference
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The design of a liquid lithium lens for a muon collider
The last stage of ionization cooling for the muon collider requires a multistage liquid lithium lens. This system uses a large ({approximately}0.5 MA) pulsed current through liquid lithium to focus the beam while energy loss in the lithium removes momentum which is replaced by linacs. The beam optics are designed to maximize the 6 dimensional transmission from one lens to the next while minimizing emittance growth. The mechanical design of the lithium vessel is constrained by a pressure pulse due to the sudden ohmic heating, and the stress on the Be window. The authors describe beam optics, the liquid lithium pressure vessel, pumping, power supplies, as well as the overall optimization of the system
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