Z. Dimcovski

Optimization of electric field distribution by free carrier injection in silicon detectors operated at low temperatures

We present a study of the modeling of the electric field distribution, which is controlled by injection and trapping of nonequilibrium carriers, in Si detectors irradiated by high neutron fluences. An analytical calculation of the electric field distribution in detectors irradiated by neutrons up to fluences of 1 /spl middot/ 10/sup 14/ to 5 /spl middot/ 10/sup 15/ cm/sup -2/ shows the possibility of reducing the full depletion voltage at low temperatures via hole injection. For this calculation, we use the detector operating parameters and equivalent neutron fluences expected for Large Hadron Collider experiments. The results of the calculation are in good qualitative agreement with published experimental data, lending strong support for the model and for an earlier proposal of electric field manipulation by free carrier injection.

Cryogenic operation of silicon detectors

This paper reports on measurements at cryogenic temperatures of a silicon microstrip detector irradiated with 24 GeV protons to a #uence of 3.5]1014 p/cm2 and of a p}n junction diode detector irradiated to a similar #uence. At temperatures below 130 K a recovery of charge collection e

Silicon detectors irradiated ''in situ'' at cryogenic temperatures

ciency and resolution is observed. Under reverse bias conditions this recovery degrades in time towards some saturated value. The recovery is interpreted qualitatively as

Recent progress in low-temperature silicon detectors

Though several studies have proved the radiation tolerance of silicon detectors at cryogenic temperatures, following room temperature irradiation, no previous investigation has studied the behaviour of detectors irradiated ‘‘in situ’’ at low temperatures. In this work, effects of irradiation of 450 GeV protons at 83 K will be presented, showing that after a dose of 1.2 � 10 15 pc m � 2 a charge collection efficiency (CCE) of 55% is reached at 200 V before the annealing. The same results were found at the end of the irradiation, after the sample has spent more then one year at room temperature. This shows that the CCE recovery by low temperature operation is not affected by the temperature of irradiation and by the reverse annealing. r 2002 Elsevier Science B.V. All rights reserved.

Cryogenic technology for tracking detectors

The CERN RD39 Collaboration studies the possibility to extend the detector lifetime in a hostile radiation environment by operating them at low temperatures. The outstanding illustration is the Lazarus effect, which showed a broad operational temperature range around 130 K for neutron irradiated silicon detectors.

Radiation hard position-sensitive cryogenic silicon detectors: the Lazarus effect

A low-mass cryogenic cooling technique for silicon sensor modules has been developed in the framework of the RD39 Collaboration at CERN. A prototype low-mass beam tracker cryostat has been designed, constructed and tested for applications in fixed target experiments. We shall report here briefly the main features and results of the system.

Charge collection efficiency recovery in heavily irradiated silicon detectors operated at cryogenic temperatures

The discovery of the so-called Lazarus e!ect, namely the recovery of the charge collection e

Irradiated silicon detectors operated at cryogenic temperatures: The Lazarus effect

ciency (CCE) of irradiated silicon detectors by means of cryogenic cooling has entailed an increasing interest in the behavior of silicon detectors at cryogenic temperatures. We have measured the CCE of a silicon p}i}n diode detector previously irradiated with an equivalent #uence of 1]1015 n/cm2 neutrons of 1 MeV energy. The charge collection e

Charge collection efficiency of irradiated silicon detector operated at cryogenic temperatures

ciency has been measured at 77 K, showing that the low-temperature operation considerably decreases the bias current. This is also the case when forward voltage bias is applied, which then becomes a suitable option. In this condition, the sample shows a charge collection e

Review on the development of cryogenic silicon detectors

ciency in excess of 65% at 250 V corresponding to a most probable signal for a minimum ionizing particle of 21 000e~. ( 2000 Elsevier Science B.V. All rights reserved.