Lossy Beam Pipe HOM Load Ceramics with DC Conductivity

The procurement of material for Beam Pipe HOM loads has been a long standing problem for three major reasons: 1) the manufacturers tend to be large companies with many customers without a material specifically designed for room temperature or super conducting accelerator beam pipes, 2) as a result, the processes for manufacturing their lossy ceramics are not designed for particle free repetitive consistency required in high quality accelerator components, and 3) the processing details required for DC conductivity to reduce charging effects and secondary electron emission are not an element of the original chemistry, but a by-product of their standard processes and thus not controlled as part of their design. Muons, Inc.’s experience with room temperature lossy ceramics with SiC will be used to make lossy ceramics with graphite loading suitable for cryogenic applications. A novel process for impregnation of the lossy ceramics with conductive nanoparticles will be utilized to form the surface conductivity required to eliminate charging of the ceramics at both room temperature and superconducting temperatures. During Phase II a complete load will be assembled from the materials designed during Phase I. Graphite loaded ceramics will be designed and fabricated to yield microwave loss at 70°K and room temperature. Measurements will be made of the resulting porosity and dielectric constant after sintering. In this novel process, the test tiles will then be immersed in a liquid with suspended nanoparticles where the capillary action will draw the nanoparticles into the open surface pores where further processing in the appropriate furnace environment will melt the nanoparticles, lodging them in place. Final tests will be done to measure the dielectric constant and surface conductivity, and sealing techniques will be experimented with, using a polymer seal material like VacSeal, to eliminate particle contamination of the vacuum space. Commercial Applications and Other Benefits The novel process of impregnating slightly porous ceramics with nanoparticles to form unique structures will benefit a wide range of applications from dentistry to accelerators. The process controls established by this SBIR will make the uniformity of lossy ceramics with DC conductivity an end rather than a byproduct of other manufacturing goals.