Tommy Eriksson

The CERN antiproton decelerator (AD) in 2002: status, progress and machine development results

After 3 years of operation, the antiproton decelerator performance is close to the design specifications. A review of the improvements over the years is given, along with results of machine development sessions that have taken place at regular intervals. An outlook for 2003 with details of planned and possible changes is also presented.

The CERN Antiproton Decelerator AD: Performance, Developments and Future Possibilities

During the first 5 years of running for physics, the CERN Antiproton Decelerator (AD) has delivered antiprotons at 100 MeV/c to the ATRAP, ATHENA and ASACUSA collaborations and at 300 MeV/c to the ACE experiment. A rundown of the improvements in cycle duration, beam intensity and density over this period will be given. Limiting factors for improved performance will be discussed as well as planned and possible future improvements. Details and layout of a proposed new ring for further deceleration, ELENA, with the purpose of increasing beam density and trapping efficiency at the experiments are presented.

The ELENA facility

The CERN Antiproton Decelerator (AD) provides antiproton beams with a kinetic energy of 5.3 MeV to an active user community. The experiments would profit from a lower beam energy, but this extraction energy is the lowest one possible under good conditions with the given circumference of the AD. The Extra Low Energy Antiproton ring (ELENA) is a small synchrotron with a circumference a factor of 6 smaller than the AD to further decelerate antiprotons from the AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. ELENA ring commissioning is taking place at present and first beams to a new experiment installed in a new experimental area are foreseen in 2017. The transfer lines from ELENA to existing experiments in the old experimental area will be installed during CERN Long Shutdown 2 (LS2) in 2019 and 2020. The status of the project and ring commissioning will be reported. This article is part of the Theo Murphy meeting issue ‘Antiproton physics in the ELENA era’.