Medipix 3 and Timepix 3 Readout Chips


Both chips are readout chips for photon-counting and particle-tracking pixel detector series developed by an international collaboration led by CERN (Conseil Europeen pour la Recherche Nucleaire). The two chips have different focuses.

Medipix 3 is the third-generation Medipix chip, designed to be connected to segmented semiconductor sensors. Like its predecessor Medipix2, it operates like a camera, capturing an image of the number of times pixels are hit by particles while the electronic shutter is open. However, Medipix 3 goes further than Medipix2, enabling color imaging (large pixel 55 μm × 55 μm) and dead-time-free operation (no time interval between frames). In addition, Medipix 3 implements a new charge summation scheme at the pixel level, reducing the effect of charge diffusion and allowing the setting of appropriate thresholds to reduce the influence of fluorescence from the sensor material.

Medipix 3 application areas: adaptive optics and other visible-light or near-visible-light applications, astrophysics, metrology, education, electron microscopy, life sciences, and non-destructive testing.

The predecessor of Timepix 3 is Timepix; there is no so-called Timepix 2. Timepix 3 is a general-purpose integrated circuit suitable for readout of semiconductor and gas-filled detectors, with a focus on time-related measurements. Timepix 3 can simultaneously obtain the time when a photon hits a pixel, the photon energy, and the pixel coordinates, which is very important for particle track reconstruction.

Timepix 3 application areas: X-ray imaging, particle track reconstruction, electron microscopy, etc.

Features of the Medipix 3 chip

  • Pixel size: 55 μm × 55 μm or 110 μm × 110 μm

  • Number of pixels: 256 × 256 or 128 × 128 pixels

  • Number of pixel thresholds: 2 per pixel, 5-bit local threshold adjustment

  • Gain: high gain (HG, lower linearity, lower noise) or low gain mode (LG)

  • Counter depth: configurable as 2 × 1 bit, 2 × 4 bit, 2 × 12 bit, 1 × 24 bit

  • Operating modes: continuous or sequential data acquisition and readout

  • Tiling: three-side buttable, 0.8 mm gap

  • TSV (Through Silicon Via): ready

Features of the Timepix 3 readout chip

  • Pixel size: 55 μm × 55 μm

  • Number of pixels: 256 × 256

  • Number of pixel thresholds: 1 per pixel, 4-bit local threshold adjustment

  • Two main measurement modes: 10-bit TOT (Time Over Threshold) and 18-bit TOA (Time of Arrival), 10-bit Event Counting and 14-bit TOT accumulation

  • Supports positive charge (hole) monotonicity

  • TOA time (Time Stamp) accuracy up to 1.56 ns

  • Data-driven readout: dead-time-free, maximum pixel hit rate 40 Mhits/s/cm2

  • Tiling: three-side buttable, 1.2 mm gap

  • TSV (Through Silicon Via): ready

Main differences between Medipix and Timepix readout chips

Medipix focuses on measuring energy information, while Timepix focuses on measuring time information; Timepix 3 can also measure energy.

Due to the different focuses, the chip structures also differ.


The above content was compiled and collected by Jerry Huang of our company, for the purpose of knowledge sharing and mutual learning only. Reproduction without permission is not allowed.