Design Of The Warm Tuner For Rf Superconducting Cavity And Study On The Test System

Superconducting cavity regulating mechanism is closely related with the development ofsuperconducting cavity and superconducting accelerator. In2001, Richard Jefferson, theUnited States National Laboratory designed and developed a superconducting cavity warmtuner, according to the principle of superconducting cavity’s flatness tuning. In2006SouthKorea PEFP project, the design of the superconducting cavity warm tuner was one ofimportant works. In2011, Nanjing University plans to use RF superconducting (SRF)accelerator in the Proton Beam Application Project, first of all is the parameters test and thedesign of the warm tuner.In this article, Virtual instrument testing platform is applied, developed a SRF(Superconducting Radio Frequency) cavity flatness test system, and realized the testing of amedium-β superconducting cavity field flatness, according to the test results, combined withfield flatness perturbation test principle, the flatness of superconducting cavity field iscalculated, if the calculation results did not meet the design and manufacturing requirementsof the RF superconducting cavity, we need modulate the RF superconducting cavity flatness.In this paper, the main content is:First of all, analyzed a calculation method of the medium-β RF superconductingdumbbell cavity field frequency, and developed a calculation method with higher accuracy,then proved that the calculation method is correct and accuracy combining experiment. Andaccording to the dumbbell cavity frequency of testing methods, introduced thesuperconducting cavity flatness test and modulation theory.Second, we did mechanical design of the regulating mechanism (tuner) of the flatness ofsuperconducting cavity field. Based on the modulation theory of superconducting cavityflatness, and combined with the characteristics of superconducting cavity of the NanjingUniversity superconducting cavity, designed the five respectively composed of the tuner,which are Activity Carriage, Gearbox Carriage, Tailstock, Activity Tailstock and Bed Body.Then analyzed some problems in the process of the tuner’s design and manufacture, summarized some problems that should be paid attention to in the design of mechanical parts.Finally, set the test system of the RF superconducting cavity field flatness, detailedanalysis and design of bead-pulling system, network analyzer and microcomputer controlsystem. Microcomputer control system uses the Virtual instrument Lab VIEW software as theupper monitoring system, to control the other parts in the test system, and analyzed test results,presented the test results to the experimenter. The goal result is that when the frequency is806MHZ, smoothness is less than8%, if the test result can’t meet the goal result, we should usesuperconducting cavity flatness tuner to tune cells of the RF superconducting cavity, makefield flatness ηff<8%.