The RHIC beam abort kicker system

Abstract

The energy stored in the RHIC beam is about 200 kJ per ring at design energy and intensity. To prevent quenching of the superconducting magnets or material damage, the beam will be safely disposed of by an internal beam abort system, which includes the kicker magnets, the pulsed power supplies, and the dump absorber. Disposal of heavy ions, such as gold imposes design constraints more severe than those for proton beams of equal intensity. In order to minimize the thermal shock in the carbon-fiber dump block, the bunches must be laterally dispersed.The nominal horizontal beam deflection angle is required to vary from -1.7 to 2.5 mrad, which is obtained from five 1.22 m long kicker modules operating at a magnetic field of -3.5 T. The kickers are constructed as window frame magnets with an 50.8 by 76.2 mm aperture and are operated in the ring vacuum.The puked power supplies run at 33 kV and deliver the 12.8 us long pulse. The peak current required is -21 kA and the 50% modulation is generated by means of a pulse forming network with non-uniform characteristic impedance.

RHIC Prefire Protection Masks

“…This number is an already conservative estimate since the first few bunches will not receive enough of a kick angle to be intercepted by a mask or, likewise, a low beta triplet magnet. In addition, even a bunch with much less than the nominal deflection is supposed to hit the abort window and a deflection angle of as little as 0.82 mrad is considered covered [8]. In this case, the minimum deflection is reached after about 1 µs leading to only 10 affected bunches.…”

Measurement and Simulation of the RHIC Abort Kicker Longitudinal Impedance

“…1. The magnet is assembled with CMD5005 ferrite pieces, each 20.32 cm long, for a total length of 122 cm [1,2]. The kicker magnet is located in a tubular vacuum vessel and the connection with the Pulse Forming Network (PFN) is through a coaxial feedthrough at a gap in the middle of the side ferrites of the magnet, as show in Figure 2.…”

Advances of Transmission Line Kicker Magnets

“…Resonances, usually at medium frequencies, can efficiently be eliminated by inserting transition pieces inside the tank to electrically connect the tank flange to the kicker module at each end [31,32]. When several magnet modules are installed in a common tank, the transition between modules is done in a similar way.…”