Flux Study: How Muon Flux is Affected by Barometric Pressure and Temperature
Andie Anger and Oscar Mota


The purpose of this study was to conclude whether temperature and pressure have an effect on the fluctuation of muon flux. In order to test this, four muon detectors were set in a stacked formation and recorded data from monday night at 5 p.m. to Friday morning at 9 a.m. The coincidence was set at two-fold. Upon analysis of the data, a graph for each channel was created with a 600 second bin width, and the data points were exported to an Excel Spreadsheet. The extreme flux counts were noted, and were then tested with a two sample t-test to determine significance. These were then compared with barometric pressure and temperature data that was tested by a two sample t-test. Since the fluctuations in muon count and pressure/temperature corresponded, it was concluded that temperature was a significant factor in muon flux count.



There have been multiple studies on how muon flux is affected with barometric pressure and temperature changes. This is because with these changes come changes in the interaction of muons with atmospheric molecules and atoms. Previous studies have shown that barometric pressure decreases muon flux because there are more molecules in the muons path that can deflect the muons before they reach Earth. There is also a negative correlation with temperature. Essentially, the research question proposed was "How do temperature and barometric pressure changes affect muon flux?".



The four detectors were laid out stacked on top of one another, and the coincidence setting was set at two-fold. The data was recorded beginning Monday night at three and continued until Friday morning at 9 a.m. The data was then analyzed with a data table of corresponding temperatures and pressures and compared to see whether the extremes produced any correlation. On each graph, the bin width was 600 seconds.



The data showed that for each channel, the extreme muon flux points had no correlation with the extreme barometric pressures recorded. This was examined by a two sample t-test. However, for the extreme temperatures, the muon flux changes were significant and did correspond to significant extreme temperature changes. The extremes were determined by using the "flux.out" analysis tool to view the data points on each channel's graph. 


Discussions & Conclusions

Because statistically the variations in temperature were significant and corresponded with significant differences in the muon flux data, it can be concluded that temperature was a factor in the flux change. Barometric pressure, in the same aspect, can be concluded to not have affected the muon flux rate. Further study would include extending the time frame in which data was recorded, and looking for broader spectrum changes in temperature and pressure.



Porier, J., and T. Catanach. "Atmospheric Effects on Muon Flux at Project GRAND."Stanford University . N.p., n.d. Web. 1 Aug. 2014. <