TOUTATIS: A radio frequency quadrupole code (original) (raw)
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Parallelization of a beam dynamics code and first large scale radio frequency quadrupole simulations
Physical Review Special Topics - Accelerators and Beams, 2007
The design and operation support of hadron (proton and heavy-ion) linear accelerators require substantial use of beam dynamics simulation tools. The beam dynamics code TRACK has been originally developed at Argonne National Laboratory (ANL) to fulfill the special requirements of the rare isotope accelerator (RIA) accelerator systems. From the beginning, the code has been developed to make it useful in the three stages of a linear accelerator project, namely, the design, commissioning, and operation of the machine. To realize this concept, the code has unique features such as end-to-end simulations from the ion source to the final beam destination and automatic procedures for tuning of a multiple charge state heavyion beam. The TRACK code has become a general beam dynamics code for hadron linacs and has found wide applications worldwide. Until recently, the code has remained serial except for a simple parallelization used for the simulation of multiple seeds to study the machine errors. To speed up computation, the TRACK Poisson solver has been parallelized. This paper discusses different parallel models for solving the Poisson equation with the primary goal to extend the scalability of the code onto 1024 and more processors of the new generation of supercomputers known as BlueGene (BG/L). Domain decomposition techniques have been adapted and incorporated into the parallel version of the TRACK code. To demonstrate the new capabilities of the parallelized TRACK code, the dynamics of a 45 mA proton beam represented by 10 8 particles has been simulated through the 325 MHz radio frequency quadrupole and initial accelerator section of the proposed FNAL proton driver. The results show the benefits and advantages of large-scale parallel computing in beam dynamics simulations.
THE RADIOFREQUENCY QUADRUPOLE ACCELERATOR FOR THE LINAC4
The first stage of acceleration in Linac4, the new 160 MeV CERN H -injector, is a 352 MHz, 3-m long Radiofrequency Quadrupole (RFQ) Accelerator. The RFQ will capture a 70 mA, 45 keV beam from the RF source and accelerate it to 3 MeV, an energy suitable for chopping and injecting the beam in a conventional Drift Tube Linac. Although the RFQ will be initially operated at low duty cycle (0.1%), its design is compatible with higher duty cycle (10%) as the front-end for a possible high-intensity upgrade of the CERN linac facility. The RFQ will be of brazed-copper construction and will be built and assembled at CERN. Beam dynamics design allows for a compact structure made of a single resonant unit. Field symmetry is ensured by fixed tuners placed along the structure. In this paper we present the RF and mechanical design, the beam dynamics and the sensitivity to fabrication and to RF errors.
Design, development, and acceleration trials of radio-frequency quadrupole
Review of Scientific Instruments, 2014
A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 μm leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (∼±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D +) beam, we tested it by accelerating both the proton (H +) and D + beams. The RFQ was operated in pulsed mode and accelerated both H + and D + beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.
Development and beam test of a continuous wave radio frequency quadrupole accelerator
Physical Review Special Topics - Accelerators and Beams, 2012
The front end of any modern ion accelerator includes a radio frequency quadrupole (RFQ). While many pulsed ion linacs successfully operate RFQs, several ion accelerators worldwide have significant difficulties operating continuous wave (CW) RFQs to design specifications. In this paper we describe the development and results of the beam commissioning of a CW RFQ designed and built for the National User Facility: Argonne Tandem Linac Accelerator System (ATLAS). Several innovative ideas were implemented in this CW RFQ. By selecting a multisegment split-coaxial structure, we reached moderate transverse dimensions for a 60.625-MHz resonator and provided a highly stabilized electromagnetic field distribution. The accelerating section of the RFQ occupies approximately 50% of the total length and is based on a trapezoidal vane tip modulation that increased the resonator shunt impedance by 60% in this section as compared to conventional sinusoidal modulation. To form an axially symmetric beam exiting the RFQ, a very short output radial matcher with a length of 0:75 was developed. The RFQ is designed as a 100% oxygen-free electronic (OFE) copper structure and fabricated with a two-step furnace brazing process. The radio frequency (rf) measurements show excellent rf properties for the resonator, with a measured intrinsic Q equal to 94% of the simulated value for OFE copper. An O 5þ ion beam extracted from an electron cyclotron resonance ion source was used for the RFQ commissioning. In off-line beam testing, we found excellent coincidence of the measured beam parameters with the results of beam dynamics simulations performed using the beam dynamics code TRACK, which was developed at Argonne. These results demonstrate the great success of the RFQ design and fabrication technology developed here, which can be applied to future CW RFQs.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
A new design method-Matched and equipartitioned (EP) design method-has been proposed for radio frequency quadrupole (RFQ) dynamics design, on the considerations of preventing emittance growth and halo formation in high-intensity linacs by means of keeping beam envelope matched and energy balance within the beam, as well as avoiding structure resonances [
Integrated design method and beam dynamics simulations for the FETS radio-frequency quadrupole
2010
A 4m-long, 324MHz four-vane RFQ, consisting of four coupled sections, is currently being designed for the Front End Test Stand (FETS) at RAL in the UK. A novel design method, integrating the CAD and electromagnetic design of the RFQ with beam dynamics simulations, is being used to optimise the design of the RFQ. Basic RFQ parameters are produced with the RFQSIM code. A full CAD model of the RFQ vane tips is produced in Autodesk Inventor, based upon these parameters. This model is then imported into a field mapping code to produce a simulation of the electro-static field around the vane tips. This field map is then used to model the beam dynamics within the RFQ using General Particle Tracer (GPT). Previous studies have been carried out using field mapping in CST EM Studio. A more advanced technique using Comsol Multiphysics and Matlab, that more tightly integrates the CAD modelling, field mapping and beam dynamics simulations, is described. Results using this new method are presented and compared to the previous optimisation process using field maps from CST.
Physics design of rod type proton Radio Frequency Quadrupole linac
AAA: A Radio Frequency Quadrupole (RFQ) linac delivering 800 keV, 5 mA protons has been designed. It is envisaged as first injector of the proton driver that will be used for production of proton-rich radioactive beams in the proposed ANURIB facility. The option of rod-type structure at frequency of 80 MHz has been chosen owing to ease of mechanical fabrications and to avoid detrimental nearby dipole modes present in vane type structure. Optimization of parameters has been carried out for a viable length and power of RFQ in order to avoid any infrastructural complexity. Conventional method of keeping focusing factor and vane voltage constant along the length of RFQ has been adopted. Results of detailed beam dynamics and RF structure design, space charge induced effects and corroborative particle tracking with realistic 3D fields of modulated vane has been presented.
A multigrid-based beam dynamics code for high current proton linacs
Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366), 1999
A beam dynamics code has been developed for the design assessment of a superconducting high current proton linac for the ENEA/INFN TRASCO Project (intended for nuclear waste transmutation in a subcritical reactor). The code deals with the dynamics of a moderate energy (above tens of MeV) and high current proton beam in a beamline composed of elliptical superconducting cavities and quadrupoles. A 3D Poisson solver based on multigrid techniques has been chosen for the space charge calculations. The simulation results for the reference linac design, with a particular care to emittance growth and halo generation, are here reported.