Development of 1-D Pinhole Lyman-alpha Cameras for Neutral Fueling and Particle Transport Studies on DIII-D*

We present the design and implementation of a pinhole camera for the measurement of edge Lyman-alpha emission profiles on the DIII-D tokamak. The system consists of two cameras, each equipped with a narrowband Lyman-alpha reflective mirror, optical filter and AXUV photodiode detector array. The two cameras will provide a toroidal fan of views at 0.75 m below the midplane covering the scrape-off layer and pedestal region on both the high field and low field side. The targeted spatial resolution is ~8 mm with coverage area of ~180 mm. The Lyman-alpha camera is intended to provide an improved characterization of neutrals for DIII-D by measuring the Lyman-alpha brightness and using an Abel inversion to determine Lyman-alpha emissivity. The emissivity is used to calculate neutral density and ionization profiles in the pedestal and scrape off layer. The camera is designed to investigate divertor leakage, main chamber fueling and radial particle transport. Recent work on design, and component calibration procedures are detailed.