THP10
Tech-X, Boulder, Colorado, USA
ANL, Argonne, USA
Efficient implementation of general-purpose particle tracking on GPUs can result in significant performance benefits to large scale particle tracking and tracking-based lattice optimization simulations. We present the latest results of our work on accelerating Argonne National Lab's accelerator simulation code ELEGANT* using CUDA-enabled GPUs**. We provide a list of ELEGANT's beamline elements ported to GPUs, identify performance-limiting factors, and briefly discuss optimization techniques for efficient utilization of the device memory space, with an emphasis on register usage. We also present a novel hardware-assisted technique for efficiently calculating a histogram from a large distribution of particle coordinates, and compare this to data-parallel implementations. Finally, we discuss results of simulations performed with realistic test lattices, and give a brief outline of future work on GPU-enabled version of ELEGANT.
* M. Borland, "elegant: A Flexible SDDS-compliant Code for Accel. Simulation", APS LS-287 (2000); Y. Wang, M. Borland, Proc. of PAC07, THPAN095 (2007)
** CUDA home page: http://www.nvidia.com/cuda
THSDI1
Tech-X, Boulder, Colorado, USA
BNL, Upton, Long Island, New York, USA
Increasing the luminosity of relativistic hadron beams is critical for the advancement of nuclear physics. Coherent electron cooling promises to cool such beams significantly faster than alternative methods. We present simulations of 40 GeV/n Au79+ ions for a single pass, which consists of a modulator, an FEL amplifier and a kicker. In the modulator, the electron beam copropagates with the ion beam, which perturbs the electron beam density and velocity via anisotropic Debye shielding. Self-amplified spontaneous emission lasing in the FEL both amplifies and imparts wavelength-scale modulation on the electron beam perturbations. The modulated electric fields appropriately accelerate or decelerate the copropagating ions in the kicker. In analogy with stochastic cooling, these field strengths are crucial for estimating the effective drag force on the hadrons and, hence, the cooling time. The inherently 3D particle and field dynamics is modeled with the parallel VORPAL framework (modulator and kicker) and with GENESIS (amplifier), with careful coupling between codes. Physical parameters are taken from the CeC proof-of-principle experiment under development at Brookhaven National Lab.
