Design and operating characteristics of a CW non-synchronous traveling wave structure for a 900 MeV pulse stretcher ring

The advantages of using a low loss, high group velocity TW circuit in pulse stretcher ring applications to compensate for synchrotron radiation and parasitic losses over a wide range of beam loading conditions and to control beam spill over a wide energy range are discussed, and details of a cw 2856 MHz TW microwave structure designed to satisfy the operating requirements of the 900 MeV pulse stretcher ring at NIKHEF-K, Amsterdam are presented. The design and operating characteristics of the TW structure for this pulse stretching application are shown tabulated and graphed for a wide range of beam energy and beam loading conditions. The higher order mode (HOM) extraction, absorption and incoherency de-Q-ing techniques used in the design and fabrication of the overall assembly are described, and extracted RF signal waveforms identifying the HOM resonances are also presented. (Author) 7 refs., 5 figs., 2 tabs