  We describe a simple experimental apparatus for laser ablation of barium
monohydride (BaH) molecules and the study of their rovibrational spectra that
are relevant to direct laser cooling. We present a detailed analysis of the
properties of ablation plumes that can improve the understanding of surface
ablation and deposition technologies. A range of absorption spectroscopy and
collisional thermalization regimes has been studied. We directly measured the
Franck-Condon factor of the
$\mathrm{B}^2\Sigma^+(v'=0)\leftarrow\mathrm{X}^2\Sigma^+(v"=1)$ transition.
Prospects for production of a high luminosity cryogenic BaH beam are outlined.
This molecule is a promising candidate for laser cooling and ultracold
fragmentation, both of which are precursors to novel experiments in many-body
physics and precision measurement.
