Abstract
Trapezoidal modulation of quadrupole electrodes offers additional benefits to the concept of a radio-frequency quadrupole (RFQ). Because of the significant increase of the effective shunt impedance, RFQs with trapezoidal modulation have a reduced interelectrode voltage or resonator length as compared to conventional RFQs with sinusoidal modulation. This feature is especially valuable for RFQs operating in cw mode, since it reduces the required rf power. We develop a detailed procedure for the design of RFQ electrodes with trapezoidal modulation. With our design procedure and by properly choosing the trapezoidal cell parameters, we can easily control the peak surface fields in the RFQ to the same level as for sinusoidal cell modulation. The procedure is applied to the design of the electrodes for the ReA3 RFQ at Michigan State University.
Highlights
A radio-frequency quadrupole (RFQ) is the most essential section for radio-frequency ion accelerators nowadays
The energy gain rate and the effective shunt impedance of RFQs decreases with the beam energy
In superconducting (SRF) heavy-ion linacs, the RFQ should provide a high enough beam energy to enable the efficient use of available voltage from SRF cavities
Summary
A radio-frequency quadrupole (RFQ) is the most essential section for radio-frequency (rf) ion accelerators nowadays. Applying trapezoidal modulation to the RFQ electrodes is an easy and efficient way to increase the transit-time factor of RFQ cells and, improve the energy gain and the effective shunt impedance of the RFQ. The first RFQ was built and commissioned in the Institute for High Energy Physics (Protvino) in 1971 [8] It had a steplike modulation of electrodes (see Fig. 1, top left), which was replaced by trapezoidal modulation with a simple piecewise linear profile soon (see Fig. 1, top right) [9]. Flat semicircular vanes with a constant radius of the tip curvature and sinusoidal modulation (see Fig. 1, bottom right) were proposed at the Institute for Theoretical and Experimental Physics (Moscow) [13] to be machined by a two-dimensional (2D) milling machine equipped with a concave cutter tool. As a result of the new design procedure, we obtained the computer-aided design (CAD) model of the new electrodes for the ReA3 RFQ
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
