Master thesis defence by Bjarke Enkelund – University of Copenhagen

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Master thesis defence by Bjarke Enkelund

Title: A study of the influence of atmospheric conditions on cosmic rays

Abstract: A study of the influence of atmospheric conditions at sea level on the amount of secondary cosmic rays measured at the same altitude have been conducted. A set of analysis tools have been developed in Python 3 to perform a fit to a linear model relating changes in pressure and temperature to changes in the number of observed secondary cosmic rays for data collected with a QuarkNet Cosmic Ray Muon Detector. A set of data was collected from the 9th to the morning of the 12th November 2018 at Borupgaard Gymnasium, Ballerup DK with a stacked flux telescope setup. This dataset was analysed using the developed tools and the results of the linear fit was a unitless barometric coefficient α = −2.3 ± 0.4 and a unitless temperature coefficent  β = −0.09 ± 0.01 with a χ 2 probability of 3.9%. The obtained barometric coefficient show good agreement with other work.

A second set of fits were performed separately to each of a set of 12 sequential thirty day periods from 2017 of data from HiSPARC station 501 at Nikhef, Amsterdam NL. The HiSPARC detector was setup in a spread out shower array setup. The data was downloaded and analysed
and the results for the both coefficients show a variation in time that is not explainable by purely statistic fluctuations. The average values for the unitless coefficients for all 12 dataset was found to be α = −5.4 and β = −0.02 respectively. Comparision to previous work done on data from the same detector but from a different year indicates an agreement for the barometric coefficient.