Evolution of silicon sensors characteristics of the current CMS tracker

The CMS silicon strip tracker is the largest detector of its kind. It is expected to operate at the LHC for more than 10 years. In order to quantify aging effects, it is important to keep track of the evolution of fundamental detector properties under radiation and thermal fluctuations. Our aim is to define monitoring procedures to determine the characteristics regularly. In this paper we focus on the silicon sensorʹs full depletion voltage. We present the first results obtained with two different methods: a standard one with signal from particles and a newly developed approach based on noise. In addition we compare our output with the C − V measurements performed during the construction.