  Using conventional superconductor theory we discuss and validate a model that
describes the energy-resolving performance of an aluminium LEKID to
single-photon absorption events. While aluminium is not the optimum material
for single-photon counting applications, this material is well understood and
is used to understand the underlying device physics of these detectors. We also
discuss data analysis techniques used to extract single-photon detections from
noisy data.
