WEZBA4
University of Tennessee, Knoxville, USA
CNMS, Oak Ridge, USA
ORNL RAD, Oak Ridge, Tennessee, USA
ORNL, Oak Ridge, Tennessee, USA
The 1.4 MW Spallation Neutron Source (SNS) uses nanocrystalline diamond (NCD) foils to strip 1 GeV H− ions to protons during injection into the accumulator ring. The SNS Proton Power Upgrade will double the power deposited into the NCD foils by increasing the beam current by 50% and linac energy by 30%. This makes understanding the failure modes of the NCD foils increasingly important. In this work we report on experiments using a 30 keV, 5 mA electron gun capable of simulating SNS PPU time structure and energy deposition in NCD foils. We analyze changes to the foil with an RGA, FLIR camera, faraday cup, high definition photography, SEM, and Raman spectroscopy. We examine failure mechanisms for foils subjected to equivalent PPU conditions. Preliminary results have shown characteristic signs of foil thinning and different failure mechanisms between the electron gun and SNS beam line. Additionally, membrane cantilever structures have been synthesized and characterized to understand the material properties of the NCD. Finally, finite element thermal simulations of the suspended diamond foils have been performed, which will be used to assess and direct future foil modifications.
