There are increasing demands to use high-beam-current, high-radio-frequency (RF) power, S-band cavities in existing and newly planned accelerator projects, in order to produce a very brilliant, broadband, coherent teraherz synchrotron radiation source (or for other purposes). For optimum performance, a critical technical challenge is to replace the present low-gap-voltage RF cavity with a very high gradient superconducting cavity that has a high current (greater than100mA) in the limited available space. This project will develop an S-band cavity that provides a much higher gap voltage than the existing copper cavity and operates with a high-stored-beam current. Phase I will perform all the calculations and analyses required to define the parameters that meet the requirements for the cavity, the fundamental coupler, and High Order Mode (HOM) couplers. Several configurations will be investigated, and a conceptual design for the complete cavity system will be proposed. The design will be used for the detailed engineering and fabrication of the cavity with accessories in Phase II.
Commercial Applications and Other Benefits as described by the awardee: At the present time, no cavities and accessories are available to support high beam current (~100mA) and provide high gap voltage at S-band frequency. The high current, large aperture, single crystal niobium S-band superconducting cavity should meet the critical demands of many DOE laboratories that need high beam power in a limited space
