Time distribution analysis for flasher data and simulations in the IceCube neutrino detector
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
The IceCube neutrino observatory is located in the deep glacial ice below the South Pole. IceCube consists of over 5, 000 photomultiplier tubes regularly spaced throughout a cubic kilometre volume of ice. The photomultiplier tubes are receptive to the light produced by high energy neutrino interactions. As a means of evaluating our understanding of the physics of light propagation, a comparison was made between the data taken from artificial light sources and Monte Carlo simulations of these events. The evaluation was done by comparing the shape of the light arrival-time distributions. The three icemodels compared were the Additionally Heterogeneous Absorption (AHA), South Pole Ice - 1 (Spice) and South Pole Ice - Mie (Spice Mie). The artificial light sources used are LEDs, known as flashers, located within each of the detector modules. The data set used in this study was taken on string 63 with single- photoelectron settings (one LED). Various orientations of the flashing LED and relative position of the light source in the detector, were studied over 15 depths in instrumented ice. Through a χ2 comparison and distribution characteristics it was found that for the majority of cases, simulations which used the Spice Mie ice model matched the data best. There were, however, some isolated cases in which simulations using the Spice 1 or AHA ice models matched the flasher data best.