(56) Coincidence Spectroscopy

When most people think of nuclear and particle physics, they imagine large laboratories with huge particle accelerators, high energy, and expensive detectors. Surprisingly, such topics can be explored in the undergraduate... [ view full abstract ]

When most people think of nuclear and particle physics, they imagine large laboratories with huge particle accelerators, high energy, and expensive detectors. Surprisingly, such topics can be explored in the undergraduate laboratory. This semester I looked at certain particle interactions using a detection technique called coincidence spectroscopy, which records simultaneous (or fixed time difference) events to "see" energies of interactions. I focused on the annihilation of matter by antimatter and Compton scattering (elastic collisions between photons and electrons). I used the radioactive isotope Na-22, which decays via gamma and beta-plus decay, as a source of both antimatter and gamma-ray photons. By measuring the energy spectrum of the emitted particles with two detectors, I was able to empirically determine the mass of the electron and demonstrate the principle of conservation of momentum in interaction events.