Branching ratio measurement of the $\pi^0$ Dalitz decay at NA62

An exploratory measurement of the branching ratio of the $\pi^0 \rightarrow e^+e^- \gamma$ decay using data taken during 2018 by NA62, a fixed target kaon decay experiment based at CERN, is presented. The total number of signal events observed is 112,711 and the branching ratio was measured to be ($1.137\pm0.022)\times 10^{-2}$; the uncertainty is dominated by the systematic errors arising from the particle identification procedure and the limited MC sample size. Further work is required in order to complete and improve the precision measurement, details of which are given. A crucial part of the NA62 experiment is the KTAG detector. The KTAG contains a nitrogen based Cherenkov counter known as a CEDAR detector, used to identify minority kaons in the beam. In order to reduce the number of beam particles interacting with the gas, hydrogen can be used instead and a design of a hydrogen filled CEDAR detector is presented.