For reliable event reconstruction of Imaging Atmospheric Cherenkov Telescopes
(IACTs), calibration of the optical throughput efficiency is required. Within
current facilities, this is achieved through the use of ring shaped images
generated by muons. Here, a complementary approach is explored, achieving cross
calibration of elements of IACT arrays through pairwise comparisons between
telescopes, focussing on its applicability to the upcoming Cherenkov Telescope
Array (CTA). Intercalibration of telescopes of a particular type using
eventwise comparisons of shower image amplitudes has previously been
demonstrated to recover the relative telescope optical responses. A method
utilising the reconstructed energy as an alternative to image amplitude is
presented, enabling cross calibration between telescopes of varying types
within an IACT array. Monte Carlo studies for two plausible CTA layouts have
shown that this calibration procedure recovers the relative telescope response
efficiencies at the few percent level.Comment: 8 pages, 4 figures, accepted for publication in Astroparticle Physic
