The COMET experiment aims to search for muon to electron conversion with a sensitivity of < 10−17. The experiment will be built in two phases, with Phase-I aiming at a sensitivity of < 10−15 using a cylindrical drift chamber. The design of COMET Phase-II has a longer beamline to improve the quality of the muon beam and perform momentum selection of electrons. The detector system will include a straw tracker and a calorimeter, which will be prototyped and tested at Phase-I. Staging the experiment is very important as this allows important measurements of the beam that will lead to a better understanding of backgrounds and the muon yield. These measurements can then be used to optimise the design of COMET Phase-II and will provide an improved estimate of the sensitivity of the experiment. The construction of Phase-I already underway and data taking will start in 2016 and Phase-II is scheduled to start data taking in 2019
