Experience with antiproton stacking at injection energy in CERN’s AD

CERN’s Antiproton Decelerator (AD) started operating for physics in July 2000 and has been successfully providing experiments with antiprotons since then. Stacking antiprotons at injection energy was foreseen as a special operational mode to be used if high intensity per pulse was required for special physics needs. The implementation of antiprotons stacking at injection was commissioned in 2000 through a series of machine development sessions. Although some operation for AD users was done in this mode, the increase in intensity per cycle was offset by a longer cycle required, hence little increase in antiproton flux was obtained. This operational mode was neither been requested nor used since then. AD is being consolidated during Long Shutdown 2 (LS2). Stacking operation is not planned as baseline operation for the AD but might be required later on. This note summarises the AD side of the procedures carried out to perform stacking at injection energy during fall 2000. Its aim is to document, for future reference, methods used, problems encountered and solutions found. Some unpublished beam results are also given.