Abstract
A transformer model of ferrite kicker magnets is presented in this paper. Based on this model, an equivalent circuit is derived for which the elements can be obtained by bench measurements or by estimates from the magnet geometry. Improved formulas for the transverse coupling impedance of lumped and traveling wave kicker magnets are derived from the model and the equivalent circuit. The formulas differ from the corresponding handbook results in their dependence on the external termination or aperture aspect, respectively. The effect of ferrite properties on the transverse coupling impedance is analyzed. The model was confirmed by bench measurements with the twin-wire technique made on the full-size and half-size prototypes of the extraction kicker of the SNS accumulator ring. The application of this model to the design of the kickers allowed a significant reduction of the SNS transverse coupling impedance budget.
Highlights
The transverse coupling impedance of a circular accelerator or storage ring can cause beam instabilities and must be carefully monitored in order to keep its value within the impedance budget
The improved kicker model analyzes the total coupling impedance in terms of contributions from the uncoupled flux and the flux coupled to the external circuit
The present model leads to a general formula that states a more accurate correlation between the coupling impedance of window frame magnets and its parameters, such as geometric dimensions, external circuit impedance, and ferrite characteristics
Summary
The transverse coupling impedance of a circular accelerator or storage ring can cause beam instabilities and must be carefully monitored in order to keep its value within the impedance budget. The impedance estimates are based on the seminal paper by Nassibian and Sacherer [3] and subsequent reports by Nassibian [4,5], where the expressions for the transverse impedance of lumped and traveling wave kicker magnet are given. Their formulas have been applied by most workers, for example, to the preliminary measurements of the SNS kicker [6,7], it was recognized that the estimates show general agreement with the real but not with the imaginary part of measured values [8]. An analytical expression of the impedance due to the uncoupled flux is derived in the Appendix
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
