Magnet System of the New Electron Cooler for the CERN Antiproton Decelerator (AD) Ring

A new electron cooler for the Antiproton Decelerator (AD) ring at CERN is under construction and will be installed in the next long shutdown (2026-2028) to replace the existing 40-year-old device. This paper presents the design of the new electron cooler’s normal conducting magnet system comprising three straight solenoid sections joined by two toroidal field sections. Compared to the existing electron cooler magnet system, the new magnet system gives a factor five improvement of cooling region field quality. The field correction scheme used to achieve this improvement will be discussed in detail. The upgrade has the potential to reduce the length of the electron cooling plateaus in the AD cycle and thereby increase the number of antiprotons available to CERN’s rich antimatter physics program.