A new slip stacking RF system for a twofold power upgrade of Fermilab׳s Accelerator Complex

Abstract

Fermilab׳s Accelerator Complex has been recently upgraded, in order to increase the 120GeV proton beam power on target from about 400kW to over 700kW for NOνA and other future intensity frontier experiments. One of the key ingredients of the upgrade is the offloading of some Main Injector synchrotron operations – beam injection and RF manipulation called “slip stacking” – to the 8GeV Recycler Ring, which had until recently been used only for low-intensity antiproton storage and cooling. This required construction of two new 53MHz RF systems for the slip-stacking manipulations. The cavities operate simultaneously at Vpeak≲150kV, but at slightly different frequencies (Δf=1260Hz). Their installation was completed in September 2013. This paper describes the novel solutions used in the design of the new cavities, their tuning system, and the associated high power RF system. First results showing effective operation of the RF system, beam capture and successful slip-stacking in the Recycler Ring are presented.