  Angular Correlation of Annihilation Radiation (ACAR) is a well established
technique for the investigation of the electric structure. A major limitation
of ACAR studies is the available positron flux at a small spot on the sample.
Fore this reason, the focus of this work is put on the discussion of a newly
developed source-sample stage which uses an optimized static magnetic field
configuration to guide the positrons onto the sample. The achieved spot size is
$d_{\mathrm{FWHM}}=5.4\,$mm, with a high efficiency over the whole energy
spectrum of the $^{22}$Na positron source. The implications of the performance
of the source-sample stage are discussed with regard to 2D-ACAR measurements of
single crystalline $\alpha$-quartz, which serves as a model system for the
determination of the total resolution.
