  Aluminium monofluoride (AlF) is a promising candidate for laser cooling and
trapping at high densities. We show efficient production of AlF in a bright,
pulsed cryogenic buffer gas beam, and demonstrate rapid optical cycling on the
Q rotational lines of the $A^1\Pi \leftrightarrow X^1\Sigma^+ $ transition. We
measure the brightness of the molecular beam to be $>10^{12}$ molecules per
steradian per pulse in a single rotational state and present a new method to
determine its velocity distribution in a single shot. The photon scattering
rate of the optical cycling scheme is measured using three different methods,
and is compared to theoretical predictions of the optical Bloch equations and a
simplified rate equation model. Despite the large number of Zeeman sublevels
(up to 216 for the Q(4) transition) involved, a high scattering rate of at
least $17(2)\times 10^6$ s$^{-1}$ can be sustained using a single,
fixed-frequency laser without the need to modulate the polarisation. We deflect
the molecular beam using the radiation pressure force and measure an
acceleration of $8.7(1.5)\times 10^5$ m/s$^2$. We demonstrate that losses from
the optical cycle due to vibrational branching to $X^1\Sigma^+, v''=1$ can be
addressed efficiently with a single repump laser. Further, we investigate two
other loss channels, parity mixing by stray electric fields and
photo-ionisation. The upper bounds for these effects are sufficiently low to
allow loading into a magneto optical trap.
