A DESIGN STUDY FOR AN INTERNAL GAS-JET TARGET FOR THE HEAVY-ION STORAGE-RING CRYRING

This paper presents the design of the internal gas-jet target, CRYJET, which is being constructed for investigations of, e.g., fast ion-atom collisions in the heavy-ion storage and cooler ring CRYRING at the Ma nne Siegbahn Laboratory, Stockholm University. The goal for the design work was to create an ultra-cold He target (less than or equal to 10 mK in the longitudinal direction and 0.5 mK transverse temperature) wi th a density of similar to 10(12) atoms/cm(3). Care was taken in order to minimize the influence from the jet on the very low background pre ssure in the storage ring (similar to 10(-11) mbar) The low temperatur e is essential for the resolution in the experiments. The high density will enable us to get sufficient luminosities for investigations of p rocesses with cross sections down to the 10(-27) cm(2) range. The gas- jet target will be equipped with two recoil-ion-momentum spectrometers in order to extract detailed information about the collision dynamics .