• Question: Why do you use a massive amount of water? Why use water at all?

    Asked by merikshadow to Ben on 23 Jun 2010 in Categories: .
    • Photo: Ben Still

      Ben Still answered on 23 Jun 2010:

      We use water because light travels slower in water.

      Energetic particles with an electric charge can produce light in an effect known as cherenkov radiation Ref 1. The particles can travel faster that light does in the water. When it does it produces a flash of light, an optical version of a sonic boom – the loud bang that happens when an airplane travels faster than the speed of sound.

      And we can use this light to take a photograph of the particle interactions.

      We use lots and lots of water because the particles we want to detect interact very very rarely. So to the more water we have the more chance we have of one interacting.

      Ref1: http://en.wikipedia.org/wiki/Cherenkov_radiation

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