Production and Quality Control Improvements in the Fabrication of Diamond-Like-Carbon Guides

Stemming from the search for physics beyond the Standard Model, the goal of the UCNA collaboration is to obtain the value of Vud. The weak and axial vector coupling constants provide an effective means of determining Vud but require knowledge of the angular correlation between the spin vector of the neutron and the momentum vector of the electron during beta-minus decay. Due to their superiority in minimizing systematic errors, Ultra-Cold Neutrons (UCN) were adopted for UCNA experiments. UCN require transport guides exhibiting the properties of being minimally depolarizing, nonmagnetic, nonconductive, possessing a high Fermi potential and high specularity. Experiments have shown that quartz tubes coated with Diamond-Like Carbon (DLC) are exceptional in the aforementioned categories. Recent improvements in the production process at Virginia Tech, including a refined cleaning procedure, the installation of a target rastering system, improved monitoring diagnostics, and a new drive mechanism have been implemented yielding improved guide quality. Furthermore, the use of X-ray spectroscopy has been employed to determine the quality of the DLC guides. Results of these improvements along with analytical results from X-ray spectroscopy will be presented.