Fianl report marisa
From MariachiWiki
Marisa Aranyavickul
Final Report
Cosmic rays are high energy particles originated in outer space that strike the Earth. In this lab, we tried to investigate the properties of the cosmic ray to have a better understanding of the particles through the use of scintillators that detect the number of particles passing through them. Our goal is to determine if there is any correlation of relative distance to the rate of detector and the velocity of the particles.
The first part of the experiment is to determine if the relative distance between the two detectors would affect the rate of cosmic ray count. We hypothesized that the larger the distance between the detectors, the lower the number of cosmic ray particles are counted. The experiment was carried out by using the distance between the detectors as a variable. We used DAQ computer program that counts the particles that run through the detectors by running it at certain distance.
Our results can be illustrated by the graph.
By analyzing the graph, we believe that the graph shows an exponential curve of decreasing rate equal to the square of the increasing distance between the detectors. We verified the our assumption by graphing the ln[rate] vs distance to see if the graph gives a straight line.
We conclude that number of cosmic ray counts over a certain period of time decreases exponentially with the increasing distance between the two detectors. By analyzing the results, we also learned that cosmic ray particles travel in different directions. If cosmic rays were to travel from one direction, the increasing relative distance between the detectors would not affect the counting rate of the detectors. More cosmic particles are able to travel through both the detector and are counted when the detectors are near each other because the solid angle that represents the range of direction the particles could come from is greater. As the detectors are further apart, the solid angle decreases in size. Thus, smaller range of direction the particle could travel from decrease, and fewer cosmic rays could hit both the detectors.
The goal of the second experiment is to figure out the velocity of the cosmic ray particles. Ws measured the time difference between the two pulses that are sent to teach the detector at two relative distance between the detectors. We used the computer program to find the time difference at distance 0 m and 2.6 m. The velocity is found by taking the slope of the time vs. distance graph.
The observed velocity is 2.79E8, which is close to the speed of light. Thus, we concluded that cosmic ray particles travel at the speed of light.
From being in the lab, I have learned many aspects of cosmic rays. I am thankful that I have a chance to participate on the hands-on experiement. I thinlk I would not have a chance to explore in this field of science anywhere else.
