Photon detection with CMOS sensors for fast imaging

Pixel detectors employed in high energy physics, aim at detecting single minimum ionizing particle with micrometric positioning resolution. Monolithic CMOS sensors succeed in this task thanks to a low equivalent noise charge per pixel around 10 to 15 e − and a pixel pitch varying from 10 to a few 10s of microns. Additionally, due to the possibility for integration of some data treatment in the sensor itself, readout time of 100 µs have been reached for 100 kilo-pixels sensors. These aspects of CMOS sensors are attractive for applications in photon imaging. For X-rays of a few keV, the efficiency is limited to a few % due to the thin sensitive volume. For visible photons, the back-thinned version of CMOS sensor is sensitive to low intensity sources, of a few hundreds of photons. But, when the back-thinned CMOS sensor is combined with a photo-cathode, the new hybrid detector resulting named EBCMOS, operates as a fast single photon imager. A first EBCMOS has been produced in 2007 and demonstrated single photon counting with low dark current capability in laboratory. It has been compared in two different biological laboratories with existing CCD-based 2D cameras for fluorescence microscopy. The current EBCMOS sensitivity is comparable to existing EMCCD as well as its frame rate. On-going developments aim at increasing this rate by, at least, an order of magnitude. We report in conclusion, the first test of a new CMOS sensor, LUCY, which reaches 1000 frames/s. 1. introductio