This is important since impurities in the crystals used lead to all kinds of fluorescence that could be mistaken for a signal from the Thorium ions. Now two groups have seen exactly the same signal in different Thorium-doped crystals which is very covincing that they have found the actual nuclear transition.
Not completely. Can't find it now, but there was research cited in the book Alex's Adventures in Numberland showing a real statistical deviation, example: Lawrences' studying Law school more frequently.
As I understand it, that is not an independent discovery but rather replication/confirmation of the results described in the original 14th of March paper by PTB & TU Wien.
This is important since impurities in the crystals used lead to all kinds of fluorescence that could be mistaken for a signal from the Thorium ions. Now two groups have seen exactly the same signal in different Thorium-doped crystals which is very covincing that they have found the actual nuclear transition.