Speaker
Description
At SNS several instrument systems are used in high radiation environments to measure the parameters or the impact of the 1 GeV proton beam at up to 1.4 MW. To measure the beam location and width, we use a luminescent coating on the target that produces light where the proton beam hits. An optical system consisting of mirrors, lenses, and an optical fiber bundle, transports the light to a camera in a low radiation environment for analysis. A tungsten-wire harp also continuously monitors the beam profile but at an upstream location and therefore only indirectly predicts the beam position at the target. The impact of the beam on the mercury filled stainless steel target is measured by in-house developed radiation-hard optical strain sensors. The strain sensors can handle 10’s of GRads of radiation and have a bandwidth of over 400 kHz. These sensors have documented the mercury response at different beam power levels and demonstrated the reduction of strain, and therefore reduction in damage, to the target due to helium bubble injection in the mercury flow to the target.
This presentation will detail the above mentioned diagnostics and also the needs for research of radiation damage to the materials used in these diagnostics, For example, research into the glue used for attaching the optical sensors could lead to longer lifetime of strain measuring system. Research of the mirrors surface damage due to the combination of radiation and chemical agents could lead to a longer lifetime of the imaging system while research into the radiation damage of the different luminescent coatings could lead to a better performing target imaging system.