BNL, Upton, Long Island, New York
KVI, Groningen
CLASSE, Ithaca, New York
In the proposed electric dipole moment (EDM) experiment, with an estimated spin coherence time of 1000 s, the spin precession due to an EDM of 10-29 e.cm will produce a change in the vertical spin component of approximately 10 μrad during the storage time. Such high sensitivity needs an extremely high accurate and reliable simulation environment of the beam and spin behavior during the storage time. Therefore, several spin-related accelerator programs have been considered and investigated. The paper surveys the computational algorithms of these approaches and provides their comprehensive analysis from multiple perspectives: accuracy, performance, extensibility, and scope of potential applications.
ANL, Argonne
MSU, East Lansing, Michigan
Many processes in Physics can be described by Partial Differential equations (PDE’s). For various practical problems, very precise and verified solutions of PDE are required; but with conventional finite element or finite difference codes this is difficult to achieve because of the need for an exceedingly fine mesh which leads to often prohibitive CPU time. We present an alternative approach based on high-order quadrature and a high-order finite element method. Both of the ingredients become possible through the use of Differential Algebra techniques. Further the method can be extended to provide rigorous error verification by using the Taylor model techniques. Application of these techniques and the precision that can be achieved will be presented for the case of 3D Laplace’s equation. Using only around 100 finite elements of order 7, verified accuracies in the range of 10-7 can be obtained.
GSI, Darmstadt
ORNL, Oak Ridge, Tennessee
IAP, Frankfurt am Main
CEA, Gif-sur-Yvette
The GSI Univeral Linear Accelerator UNILAC can accelerate all ion species from protons to uranium. Hence its DTL section is equipped with e.m. quadupoles allowing for a wide range of field strength along the section. During the last years various campaigns on the quality of high current beams at the DTL exit as function of the applied transverse focusing have been performed. Measurements were compared with up to four different high intensity beam dynamics codes. Those comparisons triggered significant improvement of the final beam quality. The codes were used to prepare an ambitious and successful beam experiment on the first observation of a space charge driven octupolar resonance in a linear accelerator.
LBNL, Berkeley, California
Tech-X, Boulder, Colorado
Laser plasma generated wakefields sustain accelerating gradient a thousand times higher than conventional accelerators, allowing acceleration of electron beams to high energy over short distances. Recently, experiments have demonstrated the production of high quality electron bunches at 1GeV within only a few centimeters. We present simulations, with the VORPAL framework, of the next generation of experiments, likely to use externally injected beams and accelerate them in a meter long 10 GeV laser plasma accelerator stage, which will operate in the quasi-linear regime where the acceleration of electrons and positrons is nearly symmetric. We will show that by using scaling of the physical parameters it is possible to perform fully consistent particle-in-cell simulations at a reasonable cost. These simulations are used to design efficient stages. In particular, we will show that we can use higher order laser modes to tailor the focusing forces, which play an important role in determining the beam quality. This makes it possible to increase the matched electron beam radius and hence the total charge in the bunch while preserving the low bunch emittance required for applications.
Northern Illinois University, DeKalb, Illinois
ANL, Argonne
Most charged particle beams under realistic conditions have Gaussian density distributions in phase space, or can be easily made so. However, for several practical applications, beams with uniform distributions in physical space are advantageous or even required. Liouville’s theorem and the symplectic nature of beam’s dynamic evolution pose constraints on the feasible transformational properties of the density distribution functions. Differential Algebraic methods offer an elegant way to investigate the underlying freedom involving these beam manipulations. Here, we explore the theory, necessary and sufficient conditions, and practicality of the uniformization of Gaussian beams from a rather generic point of view.