71–80 of 229 posts
The measurement was already confirmed by a different group: https://arxiv.org/abs/2404.12311 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.
Did anyone understand how they hold a nucleus (not an atom) in a crystal? Nucleus is charged and seeks electrons, I thought you need an electromagnetic trap for that (which the article says they don't use).
Like the other poster mentions, CaF2 is an ionic crystal, but I don’t think that’s an important detail because you wouldn’t expect a nuclear transition to be affected by the bonding state of the electrons. My guess is it’s just a convenient way to get a very dilute collection of thorium atoms without using an ion trap
American football or European football? This is like the gallon thing all over again.
standard football field size, or empirical average?
Throw in Australian Rules Football fields if you're looking for a maximum, particularly if orginal marn-grook is in the mix.
>>> For example, the Earth's gravitational field could be analyzed so precisely that it could provide indications of mineral resources Hold on how does that work? I have had a sort of sci-fi idea that sufficiently sensitive gravitational field measurements coukd detect the passing of submarines (I am not sure on the maths tbh) - which would render a lot of nuclear strategy moot. Just need to get a grasp on the maths
> If the wavelength of the laser is chosen exactly right ... then maybe a special atomic nucleus could be manipulated with a laser, namely thorium-229. On November 21, 2023, the team was finally successful: the correct energy of the thorium transition was hit exactly, the thorium nuclei delivered a clear signal for the first time. So what's the wavelength? I felt like the article left me hanging. The answer is: 148.3…
148nm is on the lower end of UV-C. It's higher-energy than the furthest ultraviolet light that the sun produces (200nm). If it were produced artificially, it'd be heavily absorbed by the atmosphere to the point of near opacity. If the visible spectrum was an octave, where the "tone" of a color wrapped around from red back to blue the way G wraps to A, it'd be the blue one octave above visible blue.
"blue above visible blue" is a good name.. hmm, a little web tool to name these would be neat ;)
https://physics.stackexchange.com/questions/296237/nuclear-t...
In summary, the answer seems to be "maybe, but why?". The laser was originally called "a solution in search of a problem", which would suggest that "why" isn't really a reason not to.
https://ask.metafilter.com/148055/Who-first-called-lasers-a-...
From the paper, the light is UV-C at around 140nm or 8.4 eV. But it has to be very precisely the right energy to cause the transition, since nuclear states don’t have any place to dump excess energy to.
The measurement was already confirmed by a different group: https://arxiv.org/abs/2404.12311 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.
The measurement was already confirmed by a different group: https://arxiv.org/abs/2404.12311 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.