Boron-Nitride Nanotube Sheets for Halo Monitor Applications

Accelerator systems that push to higher energy and higher intensity are limited by particle loss due to beam halo – the spurious components of the beam that do not obey the design trajectory of the beam core. The beam halo must be determined in terms of its shape, size, and relative extent, for adequate control and compensation. Modern high current accelerators require halo characterization at the part per million level. RadiaBeam Technologies proposes to develop a halo monitor that images the beam halo using emission generated from the stray electrons striking a thin target composed of boron-nitride nanotubes. The innovation lies in the geometry and layout of the scheme, and the innovative new material, where an elliptical foil with a centered hole allows the central beam core to pass through, whilst only imaging the halo electrons. The emitted radiation is observable using standard scientific-grade cameras and optical systems. The novel material has shown higher resistance to thermal and radiation damage than previously used materials and will survive intermittent contact with the beam core. During the Phase I we plan to design and develop the halo monitor components, including the sheets and mounts, the precision motion system, the optical detection system, and the data acquisition and analysis methods. We will test the prototype using a live beam, at the Thomas Jefferson National Accelerator Facility. Next generation accelerators will require careful evaluation of beam loss due to halo. The proposed halo diagnostic is specifically important for applications including future light sources or charged particles for non-destructive assay or testing, cancer therapy or cargo scanning. These applications inherently require accurate profile measurements of the entire beam and halo for safe and efficient operation. The developed diagnostics will have a wide range of benefits across many fields from medicine to defense and many industrial applications.