Radial compression of protons and H3+ ions in a multiring trap for the production of ultralow energy antiproton beams.

Radial compression of a proton cloud was performed in a multiring trap which was designed to trap and cool a large number of antiprotons for the production of low-energy ( 10-1000 eV ) antiproton beams. The resonance frequency for the radial compression was almost constant from 3 x 10(5) to 3 x 10(6) protons. The collision process of the trapped protons was also investigated to estimate the energy of the protons inside the trap. This technique will be applied to the ASACUSA experiment at the antiproton decelerator, CERN, to extract ultraslow antiprotons with good emittance.