Search

We have designed and built a new hodoscope for heavy ion beams consisting of two tracking stations equipped with silicon microstrip detectors operated at 130 K. Preliminary results from tests performed in the high intensity CERN-SPS Pb ion beam show that we were able to detect and identify each incoming ion up to a beam intensity of ∼107 ions/s. The beam profile could be monitored on-line with 50 μm resolution. The detector performed satisfactory even after a dose of 90±40 Grad. [Copyright &y& Elsevier]

Presents a study of the modeling of the electric field distribution, which is controlled by injection and trapping of nonequilibrium carriers, in silicon (Si) detectors irradiated by high neutron influences. Calculation of electric field distribution; Effect of the dependence of the optimal temperature for the electric field distribution in highly irradiated Si detectors; Discussion of the approach for electric field manipulation by free carrier injection.

It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, “resuscitate” when operated at temperatures below 130 K. This is often referred to as the “Lazarus effect”. The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors. [Copyright &y& Elsevier]

An increasing interest in the behaviour of silicon detectors at cryogenic temperatures has been awakened by the discovery of the so-called Lazarus effect, namely the recovery of charge collection efficiency (CCE) by means of cryogenic cooling. We measured the CCEs of three single diodes previously irradiated with different neutron fluences. The current-voltage characteristic were measured at 300 and 77 K, showing that the low-temperature operation considerably decreases the steady-state current. This is also the case when a forward voltage bias is applied, which then becomes a suitable option. At 77 K, in the case of samples irradiated with 5 x 10[sup 14] neutrons cm[sup -2], the CCE is completely recovered. A third sample irradiated with 2 x 10[sup 15] neutrons cm[sup -2] shows a 60% CCE at 250 V forward bias. [ABSTRACT FROM AUTHOR]

Presents information on a study which discussed tracking of charge collection efficiency recovery in heavily irradiated silicon detectors operated at cryogenic temperatures. Details on Lazarus effect; Description of irradiated microstrip tracker; Results of the study; Conclusion.

Abstract: We report measurements in a high-energy pion beam of the sensitivity of the edge region in “edgeless” planar silicon pad diode detectors diced through their contact implants. A large surface current on such an edge prevents the normal reverse biasing of the device, but the current can be sufficiently reduced by the use of a suitable cutting method, followed by edge treatment, and by operating the detector at low temperature. The depth of the dead layer at the diced edge is measured to be (12.5±8stat..±6syst.)μm. [Copyright &y& Elsevier]