Optical transition radiation based transverse beam diagnostics for nonrelativistic ion beams

Abstract

The usage of optical transition radiation (OTR) for profile monitoring of relativistic electron beams is well known. This paper presents the case for beam diagnostic application of OTR for nonrelativistic ion beams. In addition to expected linearly polarized transition radiation in the plane of observation, a significant component of observed radiation is unpolarized. The unpolarized contribution increases as the target is tilted toward the grazing angles with its intensity, an order of magnitude higher than the polarized radiation. This unpolarized radiation is shown to have the characteristics of OTR and is qualitatively explained as the OTR generated on a rough target surface. This increase in observed radiation can be used advantageously for transverse profile measurements. Further systematic effects such as the dependence of light yield on beam current, comparison of the measured transverse profiles with secondary electron emission based grid, target heating, and prompt nature of observed radiation are reported.