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Picosecond pixels
Pixel detectors recording very sharp pulses of charge. 

Picosecond timing

A picosecond is a millionth of a millionth of a second. A micrometer is a thousandth of a millimeter.   Our goal is to measure the positions of charged particles with a 30-picosecond timing resolution and a 30-micrometer position resolution. Today, this is not possible.  We are attempting to reach this precision using Low-Gain-Avalanche-Diode detectors. 

The challenges are : 

  • Current sensors have a dead area around them, leading to large inefficiencies when they are made into small pixels.
  • It is a challenge to fit the timing readout electronics on small pixels.
  • Radiation levels at the LHC destroy the gain layer that provides the fast signal. 
  • These detectors consume more power and generate more heat than traditional detectors due to their fast electronics.

Our group has made the first measurements of timing resolution of small-pixel LGADs.  Together with PSI, we are developing small pixel-sized readout electronics that can utilize these small sensors.