Paul Scherrer Institut

Anna Bergamaschi

Bernd Schmitt

Roberto Dinapoli

Aldo Mozzanica

A system counts photon interactions in an array of photosensitive diodes and addresses the issue of improving position resolution. Every photo-detector diode of the array is connected to a readout unit cell containing a high-gain charge-to-voltage amplifier, a shaper, at least two comparators with independent thresholds and at least one interpixel communication logic, receiving as input signals from comparator outputs of the same readout unit cell and of the neighboring readout unit cells. This logic is then connected to at least one counter, each counter followed by a counter readout. By means of the digital interpixel communication logic and the set of comparators with different thresholds in every readout unit cell, it is possible to determine the photon hit position in the detector with a higher position resolution than the physical photo-detector size including the removal of the corner effect in pixel detectors.

Single photon counting detectors in strip or pixel design having digital inter-pixel communication logic comprising a physical area of each photo-detector diode being subdivided into a plurality of smaller sections representing a plurality of virtual channels

A single photon counting detector system has a layer of photosensitive material and an N&#xd7;M array of photo-detector diodes. Each photo-detector diode has a bias potential interface and a diode output interface. The bias potential interface is connected to bias potential. An N&#xd7;M array of high gain, low noise readout unit cells is provided, one readout unit cell for each photo-detector diode. Each readout unit cell has an input interface connected to the diode output interface, a high-gain voltage amplifier with an integration capacitor at least two parallel lines of digital counters, each having a comparator with an individually selectable threshold and a gateable section to determine the counting intervals of the digital counters. A multiplexer allows access to the readout cell unit either on a per pixel basis or for several pixels in parallel to read out the digital counter to a data processor transferring the data off chip.

Growing community of inventors

Baden, Switzerland

Anna Bergamaschi