The branching ratio for the decay $K^+ to pi^+ ubar{ u}$ is sensitive to new physics; the NA62 experiment will measure it to within about 10%. To reject the dominant background from channels with final state photons, the large-angle vetoes (LAVs) mus
t detect particles with better than 1 ns time resolution and 10% energy resolution over a very large energy range. Our custom readout board uses a time-over-threshold discriminator coupled to a TDC as a straightforward solution to satisfy these requirements. A prototype of the readout system was extensively tested together with the ANTI-A2 large angle veto module at CERN in summer 2010.
