The Extreme Value Theory to estimate beam losses in high power linacs

The influence of random perturbations of high intensity accelerator elements on the beam losses is considered. This influence is analyzed with the help of the extreme value theory (EVT) to allow loss estimates for a very low fraction of the beam. Many fields of modern science and engineering have to deal with events which are rare but have significant consequences. EVT is considered to provide the basis for the statistical modeling of such extreme events (extreme variations of financial market for insurance companies or extreme wind speed for electric companies). To illustrate the application of this theory to beam losses estimates, the SPIRAL2 driver is used. This 5 mA deuteron accelerator is simulated from the output of the source to the target with a high resolution PIC modelisations (up to 1.3 million macro-particles) by using realistic external fields.