Wikipedia:Reference desk/Archives/Science/2019 December 27

= December 27 =

Absolute best radiation shield
I know that lead, plastics, and ceramics are used by humans as radiation shielding. I'm not looking for something practical. I want to know if there is an element or molecule that acts as a complete radiation shield, even if using it was completely impossible because it doesn't exist in enough quantitiy or it is too heavy or it is highly poisonous etc... After trying to find something every day for weeks, I keep getting stuck in pages discussing NASA projects and sunscreen creams. 135.84.167.41 (talk) 13:14, 27 December 2019 (UTC)
 * What type(s) of radiation are you considering? Nothing is "perfect for everything". DMacks (talk) 13:23, 27 December 2019 (UTC)
 * Can anything completely block particle radiation? Can anything completely block alpha radiation? Can anything completely block some made up radiation from your favorite scifi show? Is it truly necessary to list every form of radiation and then list what blocks it? The lists I've seen show lead for particle radiation, lead for ionizing radiation, lead for... So, is anything better than lead? 135.84.167.41 (talk) 13:39, 27 December 2019 (UTC)


 * Depleted uranium, Plasma radiation shield. NonmalignedNations (talk) 13:44, 27 December 2019 (UTC)
 * Thanks. Depleted uranium appears to be denser than lead, but the plasma shielding has more interesting articles to read. 135.84.167.41 (talk) 13:53, 27 December 2019 (UTC)
 * "A neutrino could pass through a light year of lead and not be stopped by any of the lead atoms! ". And that's before we start making things up. DMacks (talk) 13:54, 27 December 2019 (UTC)
 * Alpha radiation is apparently stopped by a sheet of paper. But if you don't care about practicality, Neutronium would be the go-to substance. I think it is used in some of the early E.E. Doc Smith novels, but I'm not quite sure. --Stephan Schulz (talk) 15:16, 27 December 2019 (UTC)
 * I assume neutron stars would block a lot of stuff trying to pass through it. So, I would place it farthest to the side of "so dense that radiation doesn't pass through it". It looks like the most dense thing we've made so far on Earth is Hassium, but it has a very short half-life. I'm reading about plasma shielding which takes a different approach than simple density. 135.84.167.41 (talk) 15:32, 27 December 2019 (UTC)
 * It may be there's no such thing as a perfect radiation shield. If you hid behind a black hole, it would still emit radiation that in a way depended on infalling matter/radiation, and it could be that this radiation somehow relayed information about what was dumped into it. So, if Romulans fired a disruptor beam into the other side of the black hole, you just might be able to use a Heisenberg compensator to recover some evidence of this from your hiding place. You would most likely not be killed by this radiated information, since the Hawking radiation strength and the fraction of it corresponding to the information about the radiation you're shielding yourself are both inversely proportional to the black hole's mass, but I'd say this is a possible hard limit as far as radiation shielding goes with the current knowledge of physics theory. 89.172.38.89 (talk) 18:05, 27 December 2019 (UTC)

Eliminating nuclear waste?
I'm hearing something that Gérard Mourou has an idea to use his Nobel prize winning technology chirped pulse amplification to do away with nuclear waste. Is this real or fake news or has he gone mad? It sounds a bit too incredible to be true but he did win the Nobel prize last year... 89.172.38.89 (talk) 18:13, 27 December 2019 (UTC)


 * He is working with the CEA in France to use CPA to change radioative atoms into atoms that are stable. He claims to have already done this along with Toshiki Tajima at UC Irvine. Their experiment is not the only one to show success in small quantities. The difference is that they plan to ramp it up to handle very large quantities of radioative materials. The existing CEA project is slated for 15 years. 135.84.167.41 (talk) 19:03, 27 December 2019 (UTC)


 * So it is real news, thanks. That sounds like damn good news for nuclear energy! 89.172.38.89 (talk) 20:24, 27 December 2019 (UTC)
 * I don't know how much of this is real and already done: he says if "he gets pulses 10,000 times faster" then he hopes he can expel neutrons out of the atoms, changing their half life. If and when that is, and beside that if he succeeds he will have to handle tons of materials releasing in a few minutes the energy they would have released in millions of years. A truly hot potato. 2003:F5:6F0D:9800:C83E:7CEF:84D9:B0DB (talk) 16:34, 5 January 2020 (UTC) Marco Pagliero Berlin