  We report an increase of up to 60% on the count rates of the rare
$^{81}\mathrm{Kr}$ and $^{85}\mathrm{Kr}$ isotopes in the Atom Trap Trace
Analysis method by enhancing the production of metastable atoms in the
discharge source. Additional atoms in the metastable $ 1s_5 $ level (Paschen
notation) are obtained via optically pumping the $1s_4-2p_6$ transition at 819
nm. By solving the master equation for the system, we identify this transition
to be the most suitable one and can describe the measured increase in
metastable population as a function of the 819-nm laser power. We calculate the
previously unknown isotope shifts and hyperfine splittings of the $1s_4-2p_6$
transition in $^{81}\mathrm{Kr}$ and $^{85}\mathrm{Kr}$, and verify the results
with count rate measurements. The demonstrated count-rate increase enables a
corresponding decrease in the required sample sizes for $^{81}\mathrm{Kr}$ and
$^{85}\mathrm{Kr}$ dating, a significant improvement for applications such as
dating of ocean water and deep ice cores.
