The RHIC injection kicker

Beam transfer from the AGS to RHIC is performed in single-bunch mode. Close spacing of the bunches in the collider requires an injection kicker with a rise time of <90 nsec, suggesting adoption of a travelling wave structure. The required vertical kick of 0.186 T·m is provided by 4 magnets, each 1.12 m long with a 48.4×48.4 mm aperture and operated at 1.6 kA. The kicker is constructed as a “C” cross section magnet, in which ferrite and high-permittivity dielectric sections alternate. The dielectric blocks provide the capacity necessary for the nominally 25 Ω characteristic impedance of the travelling wave structure, but impose the practical limit on the peak voltage, and thus current, achievable. Computer studies to minimize local electric field enhancements resulted in a configuration capable of holding ~50 kV, with adequate safety margin over the nominal 40 kV. Equivalent circuit analysis indicated the possibility of lowering the nominal voltage by operating mismatched into 20 Ω terminations without degrading the pulse shape. In this paper, the experience gained in the fabrication of the production units and the results from various single-unit tests and operation of four kickers with beam in the “Sextant Test” are reported