Medipix2/USB portable radiation camera

Advances in the field of semiconductor technologies in the last years make possible to develop new types of ionizing radiation detectors. The Medipix2 readout ASIC is an example of such a device. It is the hybrid single photon counting imaging chip (sensor and readout chips are fabricated separately). With an appropriate sensor chip on the top, it can count single X-ray photons, without any noise or dark current, at high fluxes (several Gigaphotons per cm(2) per second). It also offers excellent radiation hardness and good position resolution (256 x 256 pixels, each pixel has a 55 x 55 mu m(2) area). To make the Medipix2 imaging chip more portable for specific applications a microprocessor controlled read-out system based on the USB (Universal Serial Bus) interface has been developed. It integrates all necessary detector support into one compact device (75 x 46 mm(2)). All power supplies including sensor bias (up to 100 V) are internally derived from the voltage provided by the USB connection.