A radial compression scheme for cooled antiprotons

Abstract

A novel method is proposed for achieving a fast and efficient radial compression of antiproton clouds trapped and cooled in high magnetic field. The basic operation takes place in a low field solenoid during the transfer of the cooled antiprotons from one trap to the next. It makes use of a special device that imparts to the particles a transverse momentum which compensates exactly their initial generalized momentum. They can therefore be focused onto the solenoid axis and injected in the next high field region with a relatively small radial envelope. After standard trapping and cooling procedures a strongly radial extension is obtained. The operation can be repeated to lead to very small size of the final antiproton cloud. It can be estimated that an initial 1 cm radial extension can be reduced to 1 mm in a first stage and to less than 0.1 mm in a second stage. In this way highest densities (approaching the space charge limit) of trapped antiprotons can be obtained in a relatively short time.