  Positron physics touches on a wide-ranging variety of fields from materials
science to medical imaging to high energy physics. In this paper we present the
development of a flexible positron annihilation spectrometer appropriate for
the undergraduate laboratory. Four NaI gamma-ray ($\gamma$-ray) detectors are
connected to an oscilloscope-based data acquisition system. Coupled with the
software we developed, these detectors allow students to explore a variety of
positron and $\gamma$-ray phenomena. These include $\gamma$-ray energy
spectroscopy, Compton scattering, PET scanning fundamentals, speed of light
measurements with $\gamma$-rays, historically important polarimetry of
annihilation radiation, 3-$\gamma$ annihilation radiation observations, and
positron lifetime spectroscopy of materials. We present the developed apparatus
and examples of experiments it can perform here.
