ANL, Argonne, Illinois
Fermilab, Batavia, Illinois
Large-scale beam dynamics simulations are important in accelerator design and optimization. With the new BG/P supercomputer installed at ANL, tera-scale computing can be easily accessed. In order to make use of this emerging technology to increase the speed and efficiency of accelerator simulations, we have systematized and upgraded our software. In this paper, we will first introduce the new version of the parallel beam dynamic code PTRACK [1] updated to run on BG/P with more than 104 processors. The new PTRACK includes possibility to track ~100,000,000 particles through multiple accelerator seeds in the presence of machine errors. An example of SNS linac simulations will be presented.
[1]. J. Xu, B. Mustapha, V.N. Aseev and P.N. Ostroumov, “Parallelization of a beam dynamics code and ***”, Physics Review Special Topic-Accelerator and Beams 10, 014201, 2007.
KEK, Ibaraki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
The beam commissioning of J-PARC linac has been started since November 2006. Numerical studies have been conducted since then to analyze the experimental results obtained in the beam commissioning and deepen our understanding on the underlying physics. Particular efforts are exerted on the analyses of the transverse emittance measurement at MEBT, the phase scan measurement for DTL, and the rms width response to a quadrupole magnet variation. All the measurements are essential to realize a fine tuning of the linac, and it is of practical importance to have a physical insight into the obtained results. In these studies, various simulation tools are employed in accordance with the required capacity. In this paper, the on-going numerical studies for J-PARC linac are reviewed, and we discuss on the directions in which we should pay further efforts.
GSI, Darmstadt
IAP, Frankfurt am Main
The FAIR facility at GSI requires a dedicated proton injector for the production of secondary high intensity antiproton beams. This 325 MHz, 70 MeV machine will be the fist linac based on CH cavities operated with Konus beam dynamics. Two different options for the beam dynamics layout are under investigation including loss and error studies. Finally different RFQ output distribution are used to evaluate the injection current into the main linac.
Soreq NRC, Yavne
In this study we examine a lattice for the SARAF superconducting (SC) linac at the low velocity β range. The SC Half Wave Resonator cavities in the first cryostat have been optimized for a geometric β=0.09 and hence the β=0.0567 ions coming from the RFQ are mismatched. We developed a semi adiabatic tuning method for the low β side of the SC linac. The guidelines were derived from a study of two linac lattices that were considered for the SARAF 40 MeV proton and deuteron linac, extended up to 60 MeV for the low energy part of the EURISOL driver. Simulations were made using the TRACK and GPT codes. The lattices were tested for energy gain along the linac, emittance growth and acceptance. Further, error runs in GPT using a tail emphasis technique to enhance statistics by focusing on the bunch tail allowed us to examine compatibility of the lattices with hands-on maintenance requirements. We find our study relevant for other linacs that start with SC cavities right after the RFQ, such as SPIRAL2, and maybe IFMIF too, which are designed to start with similar β mismatch at the low β range.
Soreq NRC, Yavne
ACCEL, Bergisch Gladbach
The Soreq Applied Research Accelerator Facility (SARAF) is built to be used for basic research, medical research, neutron based non-destructive testing and radio-pharmaceuticals development and production. The accelerator, designed and constructed by Accel Instruments GmbH, starts with a 5 mA, 20 keV/u ECR ion source. A LEBT transports the beam and matches it to a normal-conducting 4-rod RFQ. The RFQ bunches the beam at a frequency of 176 MHz 4 mA ions and accelerate the ions to 1.5 MeV/u. A 0.65 m long MEBT transports and matches the beam into the superconducting linac. The 20 m long linac is composed of six cryostats that contain a total of 44 half-wave resonators optimized for β0=0.09 and 0.15, which are kept at a temperature of 4.5 K by liquid helium. In order to achieve the dose rate criterion for hands-on maintenance, beam loss is limited to 1 nA/m. Extensive beam dynamics simulations, including error analysis with high statistics, indicate that beam loss will indeed be below the above mentioned criterion. Currently, Phase I of the SARAF linac, including the ion source, LEBT, RFQ, MEBT and the first SC cryostat, is installed on site and is undergoing commissioning.
ORNL RAD, Oak Ridge, Tennessee
ORNL, Oak Ridge, Tennessee
Space charge effect has an impact on emittance measurement of low energy H- ion beam injected into the SNS RFQ. This paper presents numerical investigations of space charge effect of the beam on transverse emittance measurement using an Allison style scanner attached to the front-end test stand at SNS. The investigations are based on mathematical modelling the emittance measurement by the scanner taking into account space charge of the beam. We present a method of emittance data analysis that includes the modelling and allows more accurate measurements of the emittance. We also give an example of the emittance measurement with the scanner applying the developed method.
ORNL, Oak Ridge, Tennessee
GSI, Darmstadt
GANIL, Caen
The focus of the Working group B was to discuss the following questions:
- Summarize the state of the art in linac simulation capabilities. What are the weaknesses? What developments are needed?
- Summarize recent developments in benchmarking experimental data with simulations. What critical experiments are needed to further refine the theory and simulations?
- Summarize the present understanding and limitations of linac beam dynamics in operating linacs.
- Summarize the primary limitations to beam intensity in existing high-intensity linear accelerators.
- Summarize the key open questions in the beam dynamics of high-intensity linacs and opportunities to advance the field.