Medipix2: a 64-k Pixel readout Chip with 55-um Square Elements Working in Single Photon Counting Mode

D. San Segundo Bello, R. Campbell, R. Dinapoli, X. Llopart, E. Pernigotti

    Research output: Contribution to journalArticleAcademicpeer-review

    638 Citations (Scopus)

    Abstract

    The Medipix2 chip is a pixel-detector readout chip consisting of 256 /spl times/ 256 identical elements, each working in single photon counting mode for positive or negative input charge signals. Each pixel cell contains around 500 transistors and occupies a total surface area of 55 /spl mu/m /spl times/ 55 /spl mu/m. A 20-/spl mu/m wide octagonal opening connects the detector and the preamplifier input via bump bonding. The preamplifier feedback provides compensation for detector leakage current on a pixel by pixel basis. Two identical pulse height discriminators are used to create a pulse if the preamplifier output falls within a defined energy window. These digital pulses are then counted with a 13-b pseudorandom counter. The counter logic, based in a shift register, also behaves as the input-output register for the pixel. Each cell also has an 8-b configuration register which allows masking, test-enabling and 3-b individual threshold adjust for each discriminator. The chip can be configured in serial mode and readout either serially or in parallel. The chip is designed and manufactured in a 6-metal 0.25-/spl mu/m CMOS technology. First measurements show an electronic pixel noise of 140 e~ root mean square (rms) and an unadjusted threshold variation around 360 e~ rms.
    Original languageEnglish
    Pages (from-to)2279-2283
    JournalIEEE transactions on nuclear science
    Volume49
    Issue number5
    DOIs
    Publication statusPublished - 2002

    Keywords

    • METIS-208325

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