Granata et al.: Cryogenic technology for tracking detectors. Borer et al.: Charge collection efficiency of irradiated silicon detector operated at cryogenic temperatures. ^ Vittorio Giulio Palmieri Kurt Borer Stefan Janos Cinzia Da Viá Luca Casagrande (1998), "Evidence for charge collection efficiency recovery in heavily irradiated silicon detectors operated at cryogenic temperatures", Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 413, no. 2–3, pp. 475–478, Bibcode: 1998NIMPA.413.475P, doi: 10.1016/S0168-9002(98)00673-1.Thanks to the Lazarus effect, silicon detectors have been proven to be able survive radiation doses in excess of 90 GRad and they have been proposed for future high luminosity experiments.
The understanding of this has been detailed in a number of papers. Trapping of electrons and holes generated by particles traversing the detector is then prevented and little or no signal is lost. This leads to a large fraction of 'traps' becoming filled and therefore inactive. This leads to low signal-to-noise ratios that in turn can prevent the detection of the traversing particle.Īt cryogenic temperatures, however, once an electron or hole, resulting from ionization or from detector leakage current, is trapped in a local defect, it remains trapped for a long time due to the very low thermal energy of the lattice. Consequently the measured signal is smaller than it should be. The explanation of this phenomenon, known as the Lazarus effect, is related to the dynamics of the induced defects in the semiconductor bulk.Īt room temperature radiation damage induced defects temporarily trap electrons and holes resulting from ionization, which are then emitted back to the conduction band or valence band in a time that is typically longer than the read-out time of the connected electronics. However in 1997, Vittorio Giulio Palmieri, Kurt Borer, Stefan Janos, Cinzia Da Viá and Luca Casagrande at the University of Bern (Switzerland) found out that at temperatures below 130 kelvins (about −143 degrees Celsius), dead detectors apparently come back to life. Radiation damage produced by relativistic lead ions from the SPS beam hitting a silicon microstrip detector of the NA50 experiment at CERN
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