Evaluating Sun Sensors for the PUEO Navigation System

Neutrinos serve as a “cosmic messenger” due to their low probability of interacting with matter and neutral charge. This makes observing ultrahigh energy (UHE) neutrinos a unique opportunity to learn about the origins of UHE cosmic rays. The Payload for Ultrahigh Energy Observations (PUEO) is a balloon experiment that will fly above Antarctica with the goal of utilizing the Antarctic ice for a neutrino detector of great size. If UHE neutrinos interact with the ice, Askaryan radiation occurs which emits a signal that can be detected by PUEO. In order to know the direction of an incident neutrino, PUEO must determine its orientation upon detecting the emission. To support its primary navigation system, PUEO will use sun sensors along with the position of the Sun to determine the payload's orientation. The sun sensors each contain a duolateral position sensing detector (PSD) that determines the position of the Sun relative to itself. Each sensor is tested to evaluate its performance and calibrate for dark current. This contribution discusses these evaluation and calibration methods which aim to improve the accuracy of the orientation determined from the sensors.