AKARI NEP Survey sources at 18um

We describe a procedure using a point source filtering algorithm to remove background structure and a minimum variance method for our source extraction and photometry that delivers the optimum signal to noise for our extracted sources, confirming this by comparison with standard photometry methods.

The final source counts are complete and reliable over three orders of magnitude in flux density, resulting in sensitivities (80 per cent completeness) of 0.15 and 0.3mJy for the NEP-Deep and NEP-Wide surveys, respectively, a factor of 1.3 deeper than previous catalogues constructed from this field. The differential source counts exhibit a characteristic upturn from Euclidean expectations at around a milliJansky and a corresponding evolutionary bump between 0.2-0.4mJy consistent with previous mid-infrared surveys with ISO and Spitzer at 15 and 24{mu}m.