LASER COOLING OF CA+ IONS AND OBSERVATION OF COLLISION EFFECTS

This paper describes our recent experimental results on trapping and l aser cooling of Ca+ ions. The measurement of the characteristics of la ser-cooled Ca+ ions in an rf quadrupole ion trap, such as the fluoresc ence line shape and phase transition, is described. Observation of two types of collision-induced ''quantum jumps'' of a Ca+ ion in a backgr ound gas of H-2 or air is also described. Since the rate of the collis ion-induced jumps is very high for Ca+, it is necessary to achieve an extremely high vacuum condition for frequency standard applications.