  In this paper we investigate the feasibility of Zeeman slowing calcium
monofluoride (CaF) molecules originating from a cryogenic buffer gas cell. We
measure the $A^2\Pi_{1/2} (v=0, J=\frac{1}{2}) - X^2\Sigma_{1/2} (v=0, N=1)$
hyperfine spectrum of CaF in the Paschen-Back regime and find excellent
agreement with theory. We then investigate the scattering rate of the molecules
in a molecular Zeeman slower by illuminating them with light from a 10mW broad
repumper and a 10mW multi-frequency slowing laser. By comparing our results to
theory we can calculate the photon scattering rate at higher powers, leading to
a force profile for Zeeman slowing. We show results from a simple 1D simulation
demonstrating that this force is both strong and narrow enough to lead to
significant compression, and slowing of the molecules to trappable velocities.
