34,588 research outputs found
Accurate and efficient spin integration for particle accelerators
Accurate spin tracking is a valuable tool for understanding spin dynamics in
particle accelerators and can help improve the performance of an accelerator.
In this paper, we present a detailed discussion of the integrators in the spin
tracking code gpuSpinTrack. We have implemented orbital integrators based on
drift-kick, bend-kick, and matrix-kick splits. On top of the orbital
integrators, we have implemented various integrators for the spin motion. These
integrators use quaternions and Romberg quadratures to accelerate both the
computation and the convergence of spin rotations. We evaluate their
performance and accuracy in quantitative detail for individual elements as well
as for the entire RHIC lattice. We exploit the inherently data-parallel nature
of spin tracking to accelerate our algorithms on graphics processing units.Comment: 43 pages, 17 figure
Technologies for Delivery of Proton and Ion Beams for Radiotherapy
Recent developments for the delivery of proton and ion beam therapy have been
significant, and a number of technological solutions now exist for the creation
and utilisation of these particles for the treatment of cancer. In this paper
we review the historical development of particle accelerators used for external
beam radiotherapy and discuss the more recent progress towards more capable and
cost-effective sources of particles.Comment: 53 pages, 13 figures. Submitted to International Journal of Modern
Physics
The FLASHForward Facility at DESY
The FLASHForward project at DESY is a pioneering plasma-wakefield
acceleration experiment that aims to produce, in a few centimetres of ionised
hydrogen, beams with energy of order GeV that are of quality sufficient to be
used in a free-electron laser. The plasma wave will be driven by high-current
density electron beams from the FLASH linear accelerator and will explore both
external and internal witness-beam injection techniques. The plasma is created
by ionising a gas in a gas cell with a multi-TW laser system, which can also be
used to provide optical diagnostics of the plasma and electron beams due to the
<30 fs synchronisation between the laser and the driving electron beam. The
operation parameters of the experiment are discussed, as well as the scientific
program.Comment: 19 pages, 9 figure
Overview of Plasma Lens Experiments and Recent Results at SPARC_LAB
Beam injection and extraction from a plasma module is still one of the
crucial aspects to solve in order to produce high quality electron beams with a
plasma accelerator. Proper matching conditions require to focus the incoming
high brightness beam down to few microns size and to capture a high divergent
beam at the exit without loss of beam quality. Plasma-based lenses have proven
to provide focusing gradients of the order of kT/m with radially symmetric
focusing thus promising compact and affordable alternative to permanent magnets
in the design of transport lines. In this paper an overview of recent
experiments and future perspectives of plasma lenses is reported
Introduction to Machine Protection
Protection of accelerator equipment is as old as accelerator technology and
was for many years related to high-power equipment. Examples are the protection
of powering equipment from overheating (magnets, power converters, high-current
cables), of superconducting magnets from damage after a quench and of
klystrons. The protection of equipment from beam accidents is more recent,
although there was one paper that discussed beam-induced damage for the SLAC
linac (Stanford Linear Accelerator Center) as early as in 1967. It is related
to the increasing beam power of high-power proton accelerators, to the emission
of synchrotron light by electron-positron accelerators and to the increase of
energy stored in the beam. Designing a machine protection system requires an
excellent understanding of accelerator physics and operation to anticipate
possible failures that could lead to damage. Machine protection includes beam
and equipment monitoring, a system to safely stop beam operation (e.g. dumping
the beam or stopping the beam at low energy) and an interlock system providing
the glue between these systems. The most recent accelerator, LHC, will operate
with about 3 x 10 protons per beam, corresponding to an energy stored in
each beam of 360 MJ. This energy can cause massive damage to accelerator
equipment in case of uncontrolled beam loss, and a single accident damaging
vital parts of the accelerator could interrupt operation for years. This
lecture will provide an overview of the requirements for protection of
accelerator equipment and introduces various protection systems. Examples are
mainly from LHC and ESS.Comment: 20 pages, contribution to the 2014 Joint International Accelerator
School: Beam Loss and Accelerator Protection, Newport Beach, CA, USA , 5-14
Nov 2014. arXiv admin note: text overlap with arXiv:1601.0520
Multi-Architecture Monte-Carlo (MC) Simulation of Soft Coarse-Grained Polymeric Materials: SOft coarse grained Monte-carlo Acceleration (SOMA)
Multi-component polymer systems are important for the development of new
materials because of their ability to phase-separate or self-assemble into
nano-structures. The Single-Chain-in-Mean-Field (SCMF) algorithm in conjunction
with a soft, coarse-grained polymer model is an established technique to
investigate these soft-matter systems. Here we present an im- plementation of
this method: SOft coarse grained Monte-carlo Accelera- tion (SOMA). It is
suitable to simulate large system sizes with up to billions of particles, yet
versatile enough to study properties of different kinds of molecular
architectures and interactions. We achieve efficiency of the simulations
commissioning accelerators like GPUs on both workstations as well as
supercomputers. The implementa- tion remains flexible and maintainable because
of the implementation of the scientific programming language enhanced by
OpenACC pragmas for the accelerators. We present implementation details and
features of the program package, investigate the scalability of our
implementation SOMA, and discuss two applications, which cover system sizes
that are difficult to reach with other, common particle-based simulation
methods
The CTA Observatory
Ground-based gamma-ray astronomy has experienced a major breakthrough in the
last decade thanks to the advent of new generation instruments such as
H.E.S.S., MAGIC, Milagro and VERITAS. A large variety of cosmic particle
accelerators has been unveiled, comprising supermassive black holes in the
centres of active galaxies, nearby star forming galaxies, Galactic supernova
remnants and pulsar wind nebulae, and stellar binary systems housing a compact
object. While current instruments revealed the tips of the non-thermal icebergs
in our Universe, a factor of 10 increase in sensitivity, improved angular
resolution and an extended energy coverage is required to fully explore and
understand the physics of cosmic particle acceleration. The Cherenkov Telescope
Array (CTA) will provide these performances, by deploying two arrays of
Cherenkov telescopes in the northern and southern hemispheres, allowing
full-sky coverage. In this paper we summarize the project status and present
the science prospects of the CTA observatory.Comment: 8 pages, Conference Proceedings: Astrophysics of Neutron Stars 2010
(AIP Conference Proceedings
Towards Laser Driven Hadron Cancer Radiotherapy: A Review of Progress
It has been known for about sixty years that proton and heavy ion therapy is
a very powerful radiation procedure for treating tumours. It has an innate
ability to irradiate tumours with greater doses and spatial selectivity
compared with electron and photon therapy and hence is a tissue sparing
procedure. For more than twenty years powerful lasers have generated high
energy beams of protons and heavy ions and hence it has been frequently
speculated that lasers could be used as an alternative to RF accelerators to
produce the particle beams necessary for cancer therapy. The present paper
reviews the progress made towards laser driven hadron cancer therapy and what
has still to be accomplished to realise its inherent enormous potential.Comment: 40 pages, 24 figure
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