The Effect of Granite - Part 2

Note: Diagram not to scale.

Setup

A large granite slab was placed above the detector on stands.

The detector was run in coincidence mode with and without the slab in place and in upper single mode with and without the slab in place.

The detector was oriented with a heading of N56W. All tests were run at night in minimal light conditions. Each condition was run for a total of 10 minutes.

Based off of the conclusion of the previous experiment that the rate of cosmic particle detection is directly related to light pollution, it is likely that the results of the original granite experiment, conducted in direct sunlight, were affected by this effect.

Granite Experiment part 1

Results - Coincidence Mode

The data points presented do not differ enough relative to their margins of error for a conclusion to be drawn.

Note: The error bars of both data points are covered by their data points' dots.

Assuming that the data collected accurately represents granite's effect on count rate in the experiment setup given, granite affects count rate by 139.0% ± 0.02887%

Note: This relationship is exclusive to the experiment setup used and is not universal!

Note: Error of the effect of granite was calculated using formulas obtained in the article "How to combine errors" by Robin Hogan (Hogan, "How to combine errors").

Results - Upper Single Mode

The graph shows that despite the margin of error present, the presence of granite and the radioactive elements it contains increases count rate.

This suggests that like the thorium disc, the radiation from the granite slab causes the detector to register false positives.

This conclusion contradicts the results of the first set of granite experiments, yet this trial is also the most accurate, as the systemic error caused by light pollution was eliminated and the graph's data points have low margins of error relative to the distance between them.

Thus, granite's radioactivity increases count rate.

Next Experiment!

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References

Hogan, Robin. "How to combine errors." University of Reading. Published June 2006. Accessed 30 March 2019. http://www.met.rdg.ac.uk/~swrhgnrj/combining_errors.pdf .

Experiment Setup - Photo

Note: The photo is a reconstruction of the original experiment designed to give viewers a better understanding of the experiment setup. As it is a reconstruction, all and any values displayed in the photo (heading, light level, height and orientation of the granite slab, surroundings, etc.) are not to be considered as true to the original experiment.

Note: The original experiment was conducted at night. As such, the light level shown in this photo is a drastically inaccurate representation of the light conditions of the original experiment. Since the original experiment was conducted at night, the placing of the granite slab over the detector had no measurable effect on the amount of light reaching the detector according to the light sensor used to test the light level of the trials in this experiment.

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