SCIPP QuarkNet Internship 2013


Flux Studies:
Muons & Gamma Rays

We conducted flux studies on muons and gamma rays. Our project was comprised of two parts. In the first part, we measured the effects of the height of shielding on the flux of charged particles in the vertical detection. We hypothesized that, as shielding height increased, flux would decrease in a non-linear fashion due to the non-uniform energy distribution of the charged particles in cosmic rays. Our data yielded a graph of flux vs. shielding height that decreased exponentially. We constructed an energy spectrum to explain the shape of our graph and concluded that there is a higher abundance of lower energy particles compared to higher energy particles. We also discovered the existence of electrons in cosmic ray showers in addition to muons. In the second part of our experiment, we investigated how the event rate of Compton scattering changes with a varying scattering angle. We used the Klein-Nishina formula to construct a graph of the differential cross section vs. the scattering angle and used it to form a hypothesis. We hypothesized that the distribution of the count rate with a varying scattering angle would follow the general shape of the differential cross section distribution. However, our hypothesis was disproven by our experimental results. Once we analyzed the situation, we concluded that the discrepancy between the hypothesized shape of the count rate distribution and the actual shape of the count rate distribution arose due to the fact that we inaccurately assumed the flux being emitted by the gamma ray source to be a scalar, when it actually varies inverse-squarely with the distance from the source. Once we multiplied the cosine-wave-shaped differential cross section distribution with this inverse square function, we produced a graph whose shape coincided with the shape of the graph produced from our experimental results.
Compton Scattering Experiment
Compton Scattering Experiment