A Flexible Positron Spectrometer for the Undergraduate Laboratory
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.