Conceptual design of a bipolar kicker magnet for the J-PARC-Kamioka Neutrino Project
The Japanese Hadron Facility (J-PARC) includes a ring in which the beam is accelerated from an energy of 3 GeV to 50 GeV. One of the proposed experiments, which require the beam to be extracted from this ring, is a long baseline neutrino oscillation experiment. Space constraints in the lattice of the ring result in a requirement for a novel bipolar combined function kicker that can be used for fast extraction or abort. Magnetic field pulses with a rise time of approximately 1.1/spl mu/s and 4.3/spl mu/s flat top duration are required. One of the stringent design requirements of the extraction system is a flat top ripple of less than /spl plusmn/1%. The proposed kicker system is composed of 6 kicker magnets of 1.5 m length each, powered by pulse forming lines (PFL's). To achieve the required kick angle of /spl plusmn/5.32 mrad a low characteristic impedance has been chosen. This paper discusses several different concepts for the kicker system and presents the results of investigations into options for system impedance, and kicker magnet type including transmission line, lumped inductance and hybrid-transmission line.
A fast and accurate GPU based method on simulating energy deposition for beam-target coupling with granular materials
Abstract The simulation of beam energy transfer and medium dynamics is essential in nuclear studies and designs involving the beam loading on targets. Although the existing methods are relatively mature in simulating the thermohydrodynamics of a solid or liquid target coupled with an energetic beam, they may not be entirely applicable to a complex porous medium such as granular materials with massive discrete elements. In this study, a GPU (Graphics Processing Unit) based discrete energy deposition simulation method is proposed for the thermohydrodynamical simulation of granular flow targets with beam-grain coupling. The results of physical validations show that a significant improvement in accuracy was achieved by our method compared to the equivalent homogenization method which just simplified the granular medium to a whole block. This method provides a more accurate alternative solution to the problem of calculating energy deposition on grains. Although the method is computationally intensive, it can be synchronously executed with the granular dynamics simulation owing to the powerful parallel computing capability of GPUs. Thus, the studies on the dynamical and thermal behaviors of beam-grain coupling can be conducted in a relatively fast and precise way.
Construction and 60 kV tests of the prototype pulser for the LHC injection kicker system
The European Laboratory for Particle Physics (CERN) is constructing the Large Hadron Collider (LHC). Two counter-rotating proton beams will be injected into the LHC at an energy of 450 GeV by two kicker magnet systems, producing magnetic field pulses of approximately 900 ns rise time and 6.6 /spl mu/s flat top duration with a ripple of less than /spl plusmn/0.5%. Both injection systems are composed of 4 travelling wave kicker magnets of 2.17 m length each, powered by pulse forming networks (PFNs). To achieve the high-required kick strength of 1.2 Tm, for a compact and cost efficient design, a characteristic impedance of 5 Ohms has been chosen. The design strategy for the magnets and generators has been defined after detailed analysis of existing systems. The electrical circuit has been optimised using the circuit analysis software PSpice. Most known parasitics have been modelled. A prototype PFN has been constructed at CERN and successfully tested at 60 kV. A calibration procedure has been developed and utilised for obtaining correction data for a high voltage probe and oscilloscope amplifier. Measurements carried out with a precision of approximately /spl plusmn/0.1% show that the prototype PFN conforms to the specifications and the PSpice predictions.