The CW accelerator and the MEG monitoring and calibration methods

The aim of the MEG experiment is to measure the branching ratio of the rare muon decay B= mu(+)-> e+gamma/mu(+)-> TOT at a sensitivity of approximate to 10(-13). To reach this goal, the experiment must use the most intense continuous muon beam available (approximate to 10(8) mu/s) and obtain the highest energy, time and space resolutions, today reachable. The only way to ensure that the required performances are reached and maintained during the MEG run is by the use of several complementary and redundant methods to calibrate and monitor the behaviour of all detectors. Such methods are discussed. In more detail we present the methods connected with using a Cockroft-Walton accelerator, coupled to the MEG experiment permanently.