The H1 Central Silicon Tracker

Since 1997, the HI detector at the HERA collider at DESY, Hamburg has been equipped with a two layer silicon vertex detector (CST). The CST uses double sided, double metal layer sensors; it is read out with a specifically designed analog pipeline chip (APC), the signals are transmitted optically. The whole detector has a thickness of only 0.40 g/cm, corresponding to 1.4%X-0. An asymptotic impact parameter resolution of 57 mum has been achieved. In 2001, the detector was redesigned for the HERA luminosity upgrade. It has been equipped with a new version of the readout chip APC that has been produced in radiation hard DMILL technology. (C) 2002 Elsevier Science B.V. All rights reserved.