Ultra High Energy Cosmic Ray spectral feature discovered

[notFritzArgelander]

There is a tiny graph that needs to be enlarged to see this feature.

https://phys.org/news/2020-10-feature-e ... erful.html

[yobbo89]

i'm guessing the water reduces noise,

[notFritzArgelander]

i'm guessing the water reduces noise,

Actually the water does a lot more to produce the signal than noise reduction. It makes the signal! The index of refraction of water is greater then vacuum or air. So when a charged particle zips by at close to the speed of light is makes light. The analogy is the sonic boom produced by a super sound speed aircraft. A shock of EM radiation is produced in the water because the particle is faster than the light speed in water. The photomultiplier tubes then record the light.

https://en.wikipedia.org/wiki/Cherenkov_radiation

[yobbo89]

thanks for that, now i understand its purpose