Abstract: This project is focusing on tuning the outer detector (OD) simulation of Super Kamiokande III to improve the neutrino analysis, especially for atmospheric neutrinos. The data files with approximately 28,000 muon events have been selected by fitter and separated into six different categories according to their entry positions and energies which indicate whether they travel through the tank or stop within the tank. Each category has been further selected under specific criteria to ensure quality. In addition, both “clean” through-going muon and stopping muon samples required the consistency of fitter direction between data events and Monte Carlo simulated events. In Monte Carlo simulation for Super K, there are many parameters describing detector properties. In this project, a measurement of Tyvek’s reflectivity was implemented in the Super-K simulation program. Using clean samples, the tuning process started from the easiest case – stopping muons entry on top and stopping muons entry on wall. Some parameters related to reflectivity rates were adjusted as well as different PMT efficiencies in different parts of detector. We considered quantities such as number of PMTs hit in different regions, and other cut parameters used for neutrino event selection. The consistency between data and MC was also considered for more complicated categories of muons and more parameters were taken into account such that the tuning process significantly improved the simulation of Super-K III.
Here is the complete thesis in PDF: Sinthuprasith Thesis