Recovery of radiation damage in CdTe detectors

The exposure of CdTe:Cl detectors to increasing doses/fluences of ionizing radiation seriously affects their spectroscopic performance and operation. We have investigated the recovery process of irradiated detectors by means of photon spectroscopy (241Am and 57 Co) and photoinduced current transient spectroscopy (PICTS) analyses, by studying the evolution with time of their spectroscopic performance and correlating it with the presence of defective states in the material. In our time-recovery processes, the scale varied from 1 h to 4 yr, while the temperatures of the annealing stages varied from room temperature to 380 K. We have observed an improvement of the material detecting capabilities with time at room temperature only after long times (years) and only in the case of detectors that had not been severely degraded by the irradiation. Thermal treatments were necessary to recover heavier damage. The recovery effect can be associated to the decrease in concentration of some specific defective states, thus assessing the crucial role they play in controlling the charge collection efficiency processes

[1]  Beatrice Fraboni,et al.  Deep levels and compensation in γ-irradiated CdZnTe , 2000 .

[2]  Christopher T. Russell,et al.  Gamma-ray and neutron spectrometer for the Dawn mission to 1 Ceres and 4 Vesta , 2003 .

[3]  P. Siffert,et al.  Behavior of CdTe and CdZnTe detectors following electron irradiation , 2000, 2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149).

[4]  B. Fraboni,et al.  Compensation processes in CdTe-based compounds , 2004, IEEE Transactions on Nuclear Science.

[5]  Klaus-Werner Benz,et al.  Modified compensation model of CdTe , 1998 .

[6]  Beatrice Fraboni,et al.  Defective states induced in CdTe and CdZnTe detectors by high and low energy neutron irradiation , 2003 .

[7]  Meyer,et al.  Optical investigations of defects in Cd1-xZnxTe. , 1995, Physical review. B, Condensed matter.

[8]  Peter Blood,et al.  The Electrical Characterization of Semiconductors: Majority Carriers and Electron States , 1992 .

[9]  L. Evans,et al.  Radiation damage of Schottky CdTe detectors irradiated by 200 MeV protons , 2002 .

[10]  Ralph B. James,et al.  RADIATION DAMAGE MEASUREMENTS IN ROOM-TEMPERATURE SEMICONDUCTOR RADIATION DETECTORS , 1999 .

[11]  Paul Siffert,et al.  Radiation effects on II-VI compound-based detectors , 2002 .

[12]  C. Budtz-Jørgensen,et al.  Radiation damage measurements on CZT drift strip detectors , 2003 .

[13]  B. Fraboni,et al.  Damage induced by ionizing radiation on CdZnTe and CdTe detectors , 2003, 2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515).

[14]  Frontal IBICC study of the induced proton radiation damage in CdTe detectors , 2001 .

[15]  M. Bianconi,et al.  Radiation damage induced by 2 MeV protons in CdTe and CdZnTe semiconductor detectors , 2004 .