New architecture for the analog front-end of Medipix4

Abstract The Medipix4 chip is the latest member of the family of Medipix pixel detector readout chips aimed at high rate spectroscopic X-ray imaging. Unlike its predecessors, it will be possible to tile the chip on all 4 sides permitting seamless large area coverage. This paper focuses on the development of the new Medipix4 front-end architecture capable of event-by-event data processing allowing accurate photon energy reconstruction, with charge sharing correction at an increased rate compared to Medipix3. The architecture is particularly well adapted for readout of pixelated high-Z detector materials allowing accurate energy binning of incoming hits at a fine pixel pitch. The new front-end architecture has a linear response up to 150 keV (CdTe), a count-rate capability up to 5 . 1 × 1 0 8   photons . mm − 2 s − 1 for 10% dead time loss at 10 keV (CdTe) , and an energy resolution aiming for 2.2 keV FWHM (Full Width Half Maximum) at 60 keV (CdTe). The layout accommodates sensors with either 70 μ m or 140 μ m pitch of contacts.