  Long-baseline atom interferometers, such as the one to be built by the AION
collaboration, require ultra-cold atomic clouds. These are produced by trapping
the atoms in Magneto-Optical Traps (MOTs) using high-power, narrow-linewidth
lasers. We report on the laser and optical master-slave injection locked system
used to address the 1S0 - 3P1 strontium transition at 689 nm, and on the
trapping of strontium atoms in a narrowband MOT. We demonstrate the quality of
the injection through the characterisation of the injection lock using a novel,
easy-to-assemble method which uses a double pass acousto-optic modulator (AOM)
to generate and detect a heterodyne beatnote. The reported system is used to
produce an atomic cloud at a temperature of 812 +/- 43 nK in a narrowband red
MOT.
