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| Neutrino Project |
 Title text: We definitely put the pool in a mine for shielding. It was absolutely not to hide it from the funding people. |
Explanation
A neutrino is a type of cosmic particle that very rarely interacts with matter. In nearly all cases, neutrinos pass through objects, regardless of density or composition, with no effects whatsoever.
However, there is a very small chance that a neutrino will fail to pass through some material, causing a collision. Therefore, neutrinos can be detected by constructing large pools of water, shielded from all other particles, and carefully monitoring them for the small flashes of light that occur when a neutrino does interact with one of the many water molecules within the pool. The photomultiplier tubes mentioned in the comic are used to assist in detecting these very faint flashes.
The comic jokes that these detectors were not constructed with this purpose in mind, and were instead created via financial embezzlement from a "neutrino project" that was created solely to obtain funding for a pool party. The organizers of this project supposedly only then realized that the pool could be repurposed as an actual neutrino detector. (It is unclear what, exactly, they had claimed to be building- they may have somehow obtained funding without actually specifying how their project would work at all.)
The title text elaborates on why the pool was suitable for a neutrino detector. In real life, these detectors must be heavily shielded from all other particles that might drown out the neutrino interactions, generally requiring them to be deep underground, so a surface-level pool would obviously be unsuitable for that purpose. Randall implies that the pool was built in a deep cave in order to prevent it from being noticed by the people responsible for funding the project, which could fulfill the shielding requirement but is a humorously excessive strategy for hiding a swimming pool from a small group of people.
Transcript
- [There is a large circular pool at the bottom of the panel, with a diving board and several stickfigures in and around it. Ponytail and Cueball are talking in the pool, two hairy Kidballs are passing a ball, a Kidball is jumping of the diving board, and a Ponytail with a drink and a Danish are walking along the outside of the pool.]
- Ponytail: How much trouble do you think we'll be in when they find out we used the grant money to throw a huge pool party instead?
- Cueball: We could argue that we did build a neutrino detector.
- Cueball: There's a lot of water here. A solar neutrino will probably interact with it at some point.
- Ponytail: ...Wait. Actually, if we got some photomultiplier tubes...
- [Caption below comic:]
- How the neutrino detector was invented
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