An integrated Micromegas UV-photon detector

Preliminary results of a photon detector combining a Micromegas-like multiplier coated with a UV-sensitive CsI photocathode are described. The multiplier is made in a CMOS compatible InGrid technology, which allows to postprocess it directly on the surface of an imaging IC. This method is aimed at building light-sensitive imaging detectors where all elements are monolithically integrated. We show that the CsI photocathode deposited in the InGrid mesh does not alter the device performance. Maximum gains of ∼6000 were reached in a single-grid element operated in Ar/CH4, with a 2% ion backflow fraction returning to the photocathode.