Speaker
Dr
Elena Verbitskaya
(Ioffe Physical-Technical Institute, St. Petersburg, Russian Federation)
Description
The subject of the investigation arises from the intention to upgrade the beam loss monitoring system of the Large Hadron Collider by installation of semiconductor detectors located as close as possible to the superconducting coils of the triplet magnets and immersed in superfluid helium. For this, in-situ irradiation test of Si p-on-n detectors was carried out at 1.9K at CERN PS. The results on the collected charge and the current pulse response of Si detectors irradiated to the maximum radiation fluence of 1x10^16 p/cm2, which corresponds to a dose of about 2 MGy, are described. In the measurements the collected charge Qc was determined by integrating the detector output current over the sequence of proton spills. The current pulse was generated by a laser with the 630 nm wavelength and 45 ps width and measured using Transient Current Technique. The results exhibit degradation of the collected charge with accumulated fluence at both polarities of the bias voltage and the Qc(F) dependences are well approximated using the Hecht function. It is shown that: a) detectors maintain operation at 1.9K being irradiated up to 1x10^16 p/cm2; b) the rate of the collected charge degradation is smaller at forward bias with respect to that at reverse bias; c) the charge collected in detectors irradiated up to the maximum fluence is insensitive to bias polarity; d) space charge sign inversion in the electric field region occurs at relatively low fluence ~4x10^13 p/cm2 as is for RT irradiation. The results are analyzed taking into account specific of radiation-induced defect formation at low temperature.
Author
Dr
Elena Verbitskaya
(Ioffe Physical-Technical Institute, St. Petersburg, Russian Federation)
Co-authors
Dr
Bernd Dehning
(CERN, Geneva, Switzerland)
Dr
Christoph Kurfürst
(CERN)
Dr
Härkönen Jaakko
(Helsinki Institute of Physics)
Marcin Ryszard Bartosik
(CERN)
Dr
Mariusz Sapinski
(CERN)
Nicolai Egorov
(Research Institute of Material Science and Technology)
Dr
Vladimir Eremin
(Ioffe Physical-Technical Institute, St. Petersburg, Russian Federation)
