Characterization of a high current induction accelerator electron beam via optical transition radiation from dielectric foils

Traditionally, thin metal foils are employed for optical transition radiation (OTR) beam diagnostics but the possibility of shorting accelerator insulating surfaces and modifying accelerating fields are concerns. The successful utilization of dielectric foils in place of metal ones could alleviate these issues but necessitates more understanding of the OTR data for inferring desired beam parameters because of the dielectric´s finite permittivity. Additionally, the temperature dependence of the relevant foil parameters due to beam heating should be accounted for. Here, we present and discuss sample synthetic diagnostic results of Kapton OTR spot-size measurements from the Flash X-Ray (FXR) accelerator which studies these and sightline effects. These simulations show that in some cases, the observed spot-sizes and radii are noticeably larger than the beam radii.