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.
Comparison of field quality in lumped inductance versus transmission line kicker magnets
The choice between a transmission-line and a lumped inductance kicker magnet is generally based upon kickstrength rise-time requirements: the kick-strength risetime in a lumped inductance kicker magnet is greater than for a transmission line kicker magnet. This disadvantage can be overcome by adding shunt capacitance to the lumped magnet. A lumped inductance kicker magnet may present a transient mis-match to the pulse generator: the reflections may shorten the life of the thyratron switches and transmission cables, unless other measures are taken. Circuit analysis code PSpice has been utilized to mathematically model a kicker magnet which is simulated as being broken up into various numbers of sections. In each case the values of shunt capacitors have been optimized. This paper presents the results of theoretical simulations to determine an optimum number of sections and optimum capacitor values for a kicker magnet. A field quality comparable to that of a transmission line kicker magnet can be obtained with a 3 cell lumped inductance magnet.
A slowly rotating coil system for AC field measurements of Fermilab Booster correctors
A method for measurement of rapidly changing magnetic fields has been developed and applied to the testing of new room temperature corrector packages designed for the Fermilab Booster Synchrotron. The method is based on fast digitization of a slowly rotating tangential coil probe, with analysis combining the measured coil voltages across a set of successive magnet current cycles. This paper presents results on the field quality measured for the normal and skew dipole, quadrupole, and sextupole elements in several of these corrector packages.