Optimized Optical Imaging Setup for Nonneutral Plasma Diagnostics

Images of nonneutral plasmas are commonly obtained by releasing the plasma onto an MCP/Phosphor and observing the image with a camera. The temperature of the plasmas can be obtained from the time history of the plasma particle hitting the MCP as measured by a SiPM detector. Both of these applications work best with bright (both overall brightness and individual pixel brightness), large, clear images. These properties can be enhanced with an intermediate relay lens, but standard glass lenses of an appropriate diameter (10cm) are expensive and have significant spherical aberrations as they are not in the thin lens regime. Here we report prototyping studies with a Fresnel lens and report on the magnification, image clarity, and brightness. The results from this study will be applied to plasmas at the ALPHA antimatter experiment at CERN.