The KLOE-2 High Energy Tagger detector

In order to fully reconstruct to the reaction e + e − → e + e − γ γ in the energy region of the ϕ meson production, new detectors along the ( DA Φ NE ) beam line have to be installed in order to detect the scattered e + e − . The High Energy Tagger (HET) detector measures the deviation of leptons from their main orbit by determining their position and timing so to tag γ γ physics events and disentangle them from background. The HET detectors are placed at the exit of the DA Φ NE dipole magnets, 11 m away from the IP, both on positron and electron lines. The HET sensitive area is made up of a set of 28 plastic scintillators. A dedicated DAQ electronics board based on a Xilinx Virtex-5 FPGA have been developed for this detector. It provides a MultiHit TDC with a time resolution of the order of 500 ps and the possibility to acquire data any 2.5 ns, thus allowing to clearly identify the correct bunch crossing. First results of the commissioning run are presented.