Positron Production Target with Raster Beam

There are tremendous challenges to provide a high intensity positron source capable of continuous beam delivery. It is particularly important to devise a high power (10-to-100 kW) production target with adequate heat dissipation, positron capture, and accelerator integration. Here a novel approach using a stationary target with beam dynamics manipulation is described. It is based on a few pairs of deflecting magnets to scan a high-power electron beam along a long track on the target, either in a linear raster or around a circle, and then combine the produced positrons back into an on-axis beam. Proper optics design of incident electron beam can significantly dilute the heat load and distribute evenly, thus avoid destructive focusing on a single spot, while achieving the ample production and collection of a positron beam. The fixed target assembly can allow a sufficient flow of the cooling water on the target perimeter to carry away the deposited heat without an undue temperature rise.