Maximizing the Scientific Productivity of the Nation's Particle Accelerators Using SciDAC Beam Dynamics Simulations

D. Bruhwiler¹, A. Dragt², S. Habib³, T. Katsouleas⁴, K. Ko⁵ (co-PI), W. B.Mori⁶, R. Ryne⁷ (co-PI), R. Samulyak⁸, P. Spentzouris⁹

¹ Tech-X, ² U. Maryland, ³ LANL, ⁴ USC, ⁵ SLAC, ⁶ UCLA, ⁷ LBNL, ⁸ BNL, ⁹ FNAL

Summary

The goal of the SciDAC accelerator modeling project is to establish a comprehensive terascale simulation environment for the U.S. particle accelerator community. One of the focus areas of the project is Beam Dynamics (BD) modeling. Designed to meet the needs of DOE/SC accelerator projects, especially its High Energy Physics and Nuclear Physics projects, the new modeling tools developed by the BD team of the project are now being used by accelerator physicists and engineers to help understand and improve the performance of several of the nation's existing accelerators, and to help assure the performance of future accelerators. Examples include analyzing the effects of beam-beam interactions in Fermilab's Tevatron, BNL's RHIC, and SLAC's PEP-II; modeling space-charge effects in Fermilab's Booster; and performing simulations to study and mitigate electron-cloud formation at the Large Hadron Collider, currently under construction at CERN.

1. Introduction

The nation's particle accelerators are engines of scientific and technological progress. High-energy colliders provide insight into the fundamental forces in nature and basic constituents of matter; other accelerators such as light sources and spallation neutron sources are critical to research in materials science, chemistry, and the biosciences. In order to get the most science from the nation's accelerator facilities, scientists conduct theoretical studies, experiments, and detailed numerical simulations to improve beam quality, beam intensity, and accelerator performance. Terascale accelerator modeling tools have been developed under the SciDAC project, “Advanced Computing for 21 st Century Accelerator Science and Technology,” and are now being used to perform the most detailed simulations ever performed on the nation's accelerators. The project's Beam Dynamics modeling team, which involved scientists from different national laboratories and universities, focused on developing the tools necessary to study very intense charged particle beams. Understanding the behavior of such beams propagating through the various electromagnetic structures that make up the accelerator complex is essential for the optimization of existing accelerators and the design of future accelerators. The presence of the self-fields (space-charge fields) makes this a multi-particle system, with similarities to models found in plasma and cosmology simulation, which requires very computationally intense simulations.

•  Accomplishments

A toolkit of beam dynamics codes was developed for a broad range of accelerator systems with the capability to model colliding beams and to compute space charge fields. The applications of the new tools were selected based on the needs and priorities of the accelerator community. The Beam Dynamics modeling team worked together with the scientific staff from different laboratories to model :

•  collisions in the Tevatron, RHIC, and PEP-II accelerators. These simulations were performed using the BeamBeam3D code which models the effects of two circulating beams on one another. Understanding these effects is extremely important for the Tevatron, the highest energy hadron accelerator currently used for experiments. This code was also used to perform the first-ever one million turn, one million macro-particle simulation with the full detail of the effects of both beams (strong-strong regime), using parameters of the LHC accelerator.

•  space-charge effects in the FNAL Booster, BNL Booster, and BNL AGS accelerators. These simulations were performed using the ML/Impact and Synergia frameworks, which incorporate a fully three dimensional model of space-charge. The model predictions were then compared with experiments (see Figure 1). Understanding these effects in the FNAL Booster is very important for the success of FNAL's neutrino program.

Beyond modeling specific physical effects, the effort also included the development of other needed capabilities such as numerical beam generation, beam diagnostics, and physics analysis tools. Tools required for the integration, inter-operation, and distribution of the new codes in the context of a common framework were also developed as needed. Through the collaboration with the SciDAC ISICS and SAPP program, new visualization (see Figure 2) and equation solver capabilities were also added to the beam dynamics codes.

Figure 2. V isualization of the formation of beam halos using a new hybrid technique developed to accommodate the large dynamic range in beam density.

Our future plans for beam dynamics software development include the addition of new capabilities which will enable modeling of multiple particle species and multiple physics effects in a single application. Also, through our collaboration with the APDEC ISIC, a multi-level Poisson solver will be fully integrated into our frameworks.

3. Concluding Remarks

A new set of high-fidelity beam dynamics modeling tools is being developed under the SciDAC accelerator modeling project. In order to accomplish our goals continuation of support in FY04 and FY05 is required.

For further information on this subject contact:
Dr. Panagiotis Spentzouris
Phone: 630-840-4342
E-mail: spentz@fnal.gov

back to project page