Radiation Hardness of Thin Low Gain Avalanche Detectors

Understand

Low Gain Avalanche Detectors (LGAD) are based on a n++-p+-p-p++ structure where an appropriate doping of the multiplication layer (p+) leads to high enough electric fields for impact ionization.

• Gain factors of few tens in charge significantly improve the resolution of timing measurements, particularly for thin detectors, where the timing performance was shown to be limited by Landau fluctuations.
• The main obstacle for their operation is the decrease of gain with irradiation, attributed to effective acceptor removal in the gain layer.
• Sets of thin sensors were produced by two different producers on different substrates, with different gain layer doping profiles and thicknesses (45, 50 and 80 um).