The cylindrical GEM detector for the KLOE-2 Inner Tracker

Part of the upgrade of the KLOE detector at the DAΦNE Φ-factory consists of the insertion of a tracking device around the interaction region, composed of four tracking layers with radii from 130 mm to 205 mm and an active length of 700 mm. Each layer was realized as a cylindrical triple-GEM (CGEM) kapton-based detector, a solution that allows us to keep the total material budget below 2% of X0, of utmost importance to limit the multiple scattering of low-momentum tracks at KLOE-2, and to minimize dead spaces. The peculiar readout pattern with XV strips provides a spatial resolution of about 200 μm on both views, while a dedicated readout system has been developed by the KLOE-2 collaboration. It is composed of a digital readout front-end card based on the GASTONE ASIC and a General Interface Board with a configurable FPGA architecture and Gigabit Ethernet. The construction of the four CGEM layers has been completed and the detectors have been tested with a beta source and cosmic-ray muons. The insertion inside the KLOE apparatus was performed in July 2013. The construction procedure and the results of the validation tests will be reported.