A key focus of the physics programme at the LHC is the study of head-on proton-proton collisions.
However, an important class of physics can be studied for cases where the protons narrowly miss
one another and remain intact. In such cases, the electromagnetic fields surrounding the protons
can interact producing high-energy photon-photon collisions. Alternatively, interactions mediated
by the strong force can also result in intact forward scattered protons, providing probes of quantum
chromodynamics (QCD). In order to aid identification and provide unique information about these
rare interactions, instrumentation to detect and measure protons scattered through very small
angles is installed in the beam pipe far downstream of the interaction point. I describe the ATLAS
Forward Proton (AFP) ‘Roman Pot’ detector and its performance in LHC Run 3 to date, focusing
on the alignment of the silicon tracker.