Halo Formation in Spheroidal Bunches with Self-Consistent Stationary Distributions

A new class of self-consistent 6-D phase space stationary distributions is constructed both analytically and numerically. The beam is then mismatched longitudinally and/or transversely, and we explore the beam stability and halo formation for the case of 3-D axisymmetric beam bunches using particle-in-cell simulations. We concentrate on beams with bunch length-to-width ratios varying from 1 to 5, which covers the typical range of the APT linac parameters. We find that the longitudinal halo forms first for comparable longitudinal and transverse mismatches. An interesting coupling phenomenon - a longitudinal or transverse halo is observed even for very small mismatches if the mismatch in the other plane is large - is discovered.Comment: 3 pages, 3 figures; presented at European Particle Accelerator Conference, Stockholm, Sweden (June 22-26, 1998

Design of the Superconducting Section of the SPL LINAC at CERN

In order to set up a powerful proton source for a future Neutrino Factory, increasing at the same time the flux of protons available for new and existing facilities, CERN is studying a 2.2 GeV superconducting H- linac for 4 MW beam power, called SPL. The superconducting part of this linac covers the energy range from 120 MeV to 2.2 GeV. Three sections made of 352 MHz cavities with nominal ß of 0.52, 0.7 and 0.8 bring the beam energy up to 1 GeV. From this energy, superconducting cavities from LEP, or ß =0.8 cavities, can be used to reach the final energy of 2.2 GeV. This paper covers the optimisation for the superconducting part, the beam dynamics design principles, the matching between sections, and the results of multiparticle simulations with up to 50 million particles. To demonstrate the stability of the design matched and mismatched input beams are used

Safety and stability of superconducting magnets for fusion using internally cooled conductors

Vincent Arp's computer code for the stability analysis of internally cooled conductors (ICC) has been combined with ANL's TASS code to create the code SSICC for the analysis of the safety and stability of ICC. The code has been tested against the ICC experiments of Lue, Miller, and Dresner, and applied to the FED TF coil conductor

The NuMAX Long Baseline Neutrino Factory Concept

A Neutrino Factory where neutrinos of all species are produced in equal quantities by muon decay is described as a facility at the intensity frontier for exquisite precision providing ideal conditions for ultimate neutrino studies and the ideal complement to Long Baseline Facilities like LBNF at Fermilab. It is foreseen to be built in stages with progressively increasing complexity and performance, taking advantage of existing or proposed facilities at an existing laboratory like Fermilab. A tentative layout based on a recirculating linac providing opportunities for considerable saving is discussed as well as its possible evolution toward a muon collider if and when requested by Physics. Tentative parameters of the various stages are presented as well as the necessary R&D to address the technological issues and demonstrate their feasibility.Comment: JINST Special Issue on Muon Accelerators. arXiv admin note: text overlap with arXiv:1308.0494, arXiv:1502.0164

Object-oriented accelerator design with HPF

In this paper, object-oriented design is applied to codes for beam dynamics simulations in accelerators using High Performance Fortran (HPF). This results in good maintainability, reusability, and extensibility of software, combined with the ease of parallel programming provided by HPF

Warp-X: a new exascale computing platform for beam-plasma simulations

Turning the current experimental plasma accelerator state-of-the-art from a promising technology into mainstream scientific tools depends critically on high-performance, high-fidelity modeling of complex processes that develop over a wide range of space and time scales. As part of the U.S. Department of Energy's Exascale Computing Project, a team from Lawrence Berkeley National Laboratory, in collaboration with teams from SLAC National Accelerator Laboratory and Lawrence Livermore National Laboratory, is developing a new plasma accelerator simulation tool that will harness the power of future exascale supercomputers for high-performance modeling of plasma accelerators. We present the various components of the codes such as the new Particle-In-Cell Scalable Application Resource (PICSAR) and the redesigned adaptive mesh refinement library AMReX, which are combined with redesigned elements of the Warp code, in the new WarpX software. The code structure, status, early examples of applications and plans are discussed

Self-consistent 3D simulations of longitudinal halo in rf -linacs

In order to prevent activation of the beam pipe walls and components of a high power ion accelera- tor: beam loss must be minimized. Here we present self-consistent, 3D particle-in-cell simulations of longi- tudinally mismatched beams including the effects of rf non-linearities using parameters based on the Acceler- ator Production of Tritium linac design. In particular, we explore the evolution of the longitudinal halo distri- bution, i.e., the distribution of particles in longitudinal phase space with oscillation amplitudes significantly larger than amplitudes of particles in the main body or ''core'' of the beam. When a particle reaches a suf- ficiently large amplitude longitudinally it can he lost from the rf bucket and consequently loses synchro- nism with thr rf wave. Such particles will lose energy and so be poorly matched to the transverse focusing field and consequently can be lost transversely. We compare the present simulations in which all particles contribute self-consistently to the self-field to predic- tions of a core/test particle model in which the core distribution has uniformly distributed charge and does not evolve self-consistently. Effects of self-consistent, non-linear space-charge forces, non-linear rf focusing on envelope mismatch induced beam halo are explored through comparisons of both models

Billion particle linac simulations for future light sources

In this paper we report on multi-physics, multi-billion macroparticle simulation of beam transport in a free electron laser (FEL) linac for future light source applications. The simulation includes a self-consistent calculation of 3D space-charge effects, short-range geometry wakefields, longitudinal coherent synchrotron radiation (CSR) wakefields, and detailed modeling of RF acceleration and focusing. We discuss the need for and the challenges associated with such large-scale simulation. Applications to the study of the microbunching instability in an FEL linac are also presented

Beam Loss Studies for Rare Isotope Driver Linacs Final Report

The Fortran 90 RIAPMTQ/IMPACT code package is a pair of linked beam-dynamics simulation codes that have been developed for end-to-end computer simulations of multiple-charge-state heavy-ion linacs for future exotic-beam facilities. These codes have multiple charge-state capability, and include space-charge forces. The simulations can extend from the low-energy beam-transport line after an ECR ion source to the end of the linac. The work has been performed by a collaboration including LANL, LBNL, ANL, and MSU. The code RIAPMTQ simulates the linac front-end beam dynamics including the LEBT, RFQ, and MEBT. The code IMPACT simulates the beam dynamics of the main superconducting linac. The codes have been benchmarked for rms beam properties against previously existing codes at ANL and MSU. The codes allow high-statistics runs on parallel supercomputing platforms, particularly at NERSC at LBNL, for studies of beam losses. The codes also run on desktop PC computers for low-statistics work. The code package is described in more detail in a recent publication [1] in the Proceedings of PAC07 (2007 US Particle Accelerator Conference). In this report we describe the main activities for the FY07 beam-loss studies project using this code package