  We have realized a one dimensional optical lattice for individual atoms with
a lifetime >300 s, which is 5 times longer than previously reported. In order
to achieve this long lifetime, it is necessary to laser cool the at-oms briefly
every 20 s to overcome heating due to technical fluctuations in the trapping
potential. Without cooling, we observe negligible atom loss within the first 20
s followed by an exponential decay with a 62 s time constant. We obtain
quantitative agreement with the measured fluctuations of the trapping potential
and the corresponding theoretical heating rates.
