Unit 2 had been taken offline earlier that month for maintenance, and investigators later found unexpected wear on hundreds of tubes inside both units.

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We packed tubes and tools, as well as a folding tire and spare spokes, both of which we ended up needing.

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For both modes of crystal fibre, the pattern of holes is generated by stacking hollow glass tubes a millimetre or so in diameter to form a rod several centimetres thick.

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Tubes at the top and bottom are intended to catch these flashes of light and tell scientists both the location and the intensity of the interactions.

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