We have measured the time dependence of the concentration of copper atoms in the ground and metastable states in a pulsed CuCl laser by monitoring the absorption of atomic copper lines. We found that the ground‐state population rises from a very small value at the end of the dissociation pulse to a maximum and decreases slowly after about 160 &mgr;sec. The metastable population reaches a maximum after about 40 &mgr;sec and then decreases relatively rapidly. We conclude that the minimum and optimum delay times in a double‐pulse copper halide laser are determined primarily by the slow buildup of the copper‐atom ground‐state concentration. This concentration then decays by recombination.