Senior Design Proposal

The following report describes the analysis for finding the speed of an extensive air shower produced by an ulta-high energy cosmic ray. Not only will this analysis be useful in measring the speed of cosmic ray showers but also it can help in correcting a bias in the detection instrumentation. As cosmic rays enter Earth’s upper atmosphere, they interact with nuclei, creating secondary particles that share the original particle’s energy. This process of interaction continues and forms a cascade of energetic particles. These cascades are called extensive air showers. By examining the velocity distribution of these air showers, we can figure out the composition of the primary particle. The flux of these highest energy particles is very low at about 1 km−2·y−1. Therefore two different types of detectors are used independently to detect these rare particles. The first, a fluorescence detector, detects ultraviolet light when electromagnetic radiation interacts with N2 molecules in the atmosphere. This optical signal is called a fluorescence. The second detector, a surface detector, employs Cerenkov radiation to decipher the source and intensity of the cosmic ray. Using this hybrid technology, scientists seek to find the enigmatic origin of these particles. Fluorescence detectors (FDs) at the Pierre Auger Observatory detect electromagnetic air showers produced by cosmic rays interacting with the upper atmosphere. These showers are assumed to travel at the speed of light c. Due to the way the detectors are oriented, the geometry of the shower can be measured independently of the speed it travels. Therefore, if the geometry of the shower is well known, then the actual speed of the shower can be calculated. First, I will analyze an experiment where a laser was fired