SNS TARGET BEAM PROFILE VIEWSCREEN DESIGN AND OPERATION

Abstract

A phosphor screen was installed in front of the Spallation Neutron Source (SNS) mercury target to monitor the proton beam profile for initial commissioning in April, 2006. The viewscreen was used to center the beam on the target, monitor and adjust beam profile to fit within the nominal 70mm x 200mm footprint on the target and to calibrate upstream beam diagnostics. The system was originally intended for commissioning at very low power. It was found to be a very useful diagnostic and removal was postponed until thermal limits at 10 kW were reached. This paper will discuss the optical and mechanical design of the system and results. Options for adding a similar system in the future to SNS will also be discussed.