PAMELA silicon tracking system: Experience and operation

The PAMELA cosmic-ray telescope has been launched into space on 15 June 2006 on board of the Resurs-DK1 Russian satellite and is in continuous data acquisition mode since 11 July 2006. The magnetic spectrometer of PAMELA is composed of a hollow permanent magnet with a microstrip Si tracking system inserted inside the cavity. This paper reviews the general characteristics of the tracking system and presents a preliminary analysis of a data sample acquired in flight, showing that the main performances of the Si detectors after launch are in agreement with what expected on the basis of the ground qualification tests.