From: Chiara Guazzoni <Chiara.Guazzoni@mi.infn.it> Newsgroups: milano.seminari Subject: 25-10-04 Review of Semiconductor Drift Detectors Date: Fri, 15 Oct 2004 14:59:11 +0200 Milano - Piazza Leonardo da Vinci, 32 - 20133 Milano - Italy Content-Transfer-Encoding: 7bit User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030703 X-Accept-Language: en-us, en AVVISO DI SEMINARIO Il giorno 25 ottobre 2004 alle ore 10:15 nella Sala Alfa Dip. Elettronica e Informazione Politecnico di Milano Via Golgi, 40 - Piano Terra Il Dr. Pavel REHAK del Brookhaven National Laboratory (co-inventore dei Semiconductor Drift Detectors insieme al Prof. Emilio Gatti) terra' un seminario dal titolo REVIEW OF SEMICONDUCTOR DRIFT DETECTORS Abstract About 20 years ago a new charge transport scheme for signal carriers in semiconductor detectors was suggested. Soon after, the first working example of the Silicon Drift Detector was presented. The unusual features of silicon drift detectors and similar structures was a controlled transport of signal charge carriers in a direction parallel to large surface of the wafer. At that time almost all radiation detectors made from high resistivity silicon wafer transported the signal charge in the ditrection perpendicular to the detector surface. Position sensing in these traditional detectors was accomplished by the division of electrodes, that is, by granularity of the readout. The main ideas behind this charge transport in semiconductor drift detectors will be shortly presented. Due to this transport mechanism the signal charge finally arrives to a very small electrode, called anode. The traveling time of signal carriers from the position of their creation to the anode provides the positional information for drift detectors. A single collecting strip-like electrode of the linear drift detector provides equivalenty information to all channels of a well known single -sided strip detector, however, having substantially longer read-out time. When this strip-like electrode is divided into shorter segments a detector which provides an unambiguous two coordinate readout is obtained. Such a drift detector with a modest number of readout channels is equivalent to a full blown pixel detector. Examples of vertex detectors based on silicon drift technology will be given. The most important application of silicon drift detectors is in the neighbor field of X-ray spectroscopy. The maximum advantage is taken from a very small capacitance of the collecting electrode which has a point-like shape. The small capacitance together with an improved technology of the production of detectors created a room temperature spectroscopy with the performance traditionally limited to detectors cooled down to liquid nitrogen temperature (77K). Per informazioni: Chiara Guazzoni - mailto:Chiara.Guazzoni@mi.infn.it - Tel. 02 - 23996147.