Experimental study of anomalous heating and trap instabilities in a microscopic 137Ba ion trap -: art. no. 063407

A single Ba-137(+) ion has been laser cooled to the first few vibrational states of an 80-mum radius rf quadrupole trap. Initial measurements showed no anomalous heating of the vibrational phonon for observation times up to 1 ms, corresponding to a heating rate less than 3.3 phonons/ms at a 95% confidence level. Subsequently we observed the growth of large and unstable bias voltages that were correlated with exposure to the atomic beam. After loading over 250 ions over a period of 720 days the trap became unstable, with ion lifetimes <1 min. A possible connection between this trap instability and anomalous heating observed in quantum computation experiments is discussed. An isotopically selectively laser cooling method was used to refine Ba-137 ions out of a naturally abundant cloud.