The Large-angle Photon Veto Detector for the P326 experiment at CERN

The P326 experiment at CERN plans to measure $BR(K^{+} \to \pi^{+}\nu\bar{\nu})$ with an uncertainty of ≈ 10%. The $\pi^{0}$ rejection factor should be at the level of $10^{8}$ to achieve the required signal to noise ratio. For the construction of the large-angle photon veto system, a test program of different technological solutions has started. A module based on lead and scintillating fibers has been constructed and it has been tested together with a lead/scintillator with WLS readout prototype originally developed by CKM at Fermilab and with some lead glass blocks formerly used in the OPAL calorimeter. Preliminary results on the inefficiency to electrons are presented.