The CERN Antiproton Complex and present status and future developments of the Antiproton Accumulator

This chapter discusses the CERN Antiproton Complex and Accumulator with regard to operational performance, reductions in yield, machine acceptance, and stochastic cooling systems. A proton synchrotron focuses 26 GeV/c protons from the PS onto a copper target, and antiprotons emerge from the target at various angles and momenta. The accumulator accepts antiprotons with momenta in the range 3.57 GeV/c + or - 0.75%. Antiprotons are injected and precooled in momentum space before being captured and decelerated by a radio-frequency cavity into the tail of the stack. A beam line transports the antiprotons back to the proton synchrotron where they are accelerated to 26 GeV/c and ejected to either the Intersecting Storage Rings or to the 300 GeV Super Proton Synchrotron. Performance is limited by the accumulation rate, which is measured by the ratio between the rate specified in the design report to that measured to date (the missing factor or M.F.). The missing factor is attributed to reduced yield, reduced machine acceptance, and reduced performance of the stochastic cooling systems. The antiprotons can be decelerated from 3.57 GeV/c to a momentum of 600 MeV/c and eventually transferred to the Low-Energy and Antiproton Ring (LEAR)