Detector upgrade for the KLOE 2 experiment : The calorimeter system

The upgrade of the DAΦNE machine layout and the gamma-gamma physics search require a modification of the size and position of the inner focusing quadrupoles of KLOE-2 and a tagging system based on calorimetric detectors. Therefore the realization of different new calorimeters covering the quadrupoles area and the realization of a tagging system able to detect electrons and photons in an energy range which spans from 100 up to 500 MeV are necessary. The new system named QCALT covering the quadrupoles will have a time resolution better than 1 nsec, and will improve the reconstruction of KL to 2π 0 events with photons hitting the quadrupoles. The tagging system will be made of two different sub-detectors the High Energy Tagger (HET) to identify electrons in an energy range between 400 and 500 MeV and a low energy tagger (LET) to identify electrons between 100 and 300 MeV. In this paper we’ll illustrate these detectors.