Talk:Alpha particle
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Mass-energy equivalence
Given the interconvertability of all matter and energy (have you calculated your de Broglie wavelength recently?) the same argument could be made for any type of ray, radiation, or collection of matter. Perhaps what is needed is a convention to use in naming the entries for the types of rays or radiation that have "trivial" names: alpha, beta, gamma. Whether we make the the modified term "ray" or "radiation" is of no import to me, though I think "particle" would be a stretch, since one never speaks of a gamma particle (a high energy photon) and rarely, if ever, of a beta particle (an electron).
I say call them all "radiation" and make any other entry a redirect. -- dja
- I think that "alpha radiation" and "alpha particle" are generally used in diferent contexts. Some of my research entails impinging alpha particles upon a device surface to create knock-on and knock-off damage, and the unit for measuring this is "counts" or "number of alpha particles", while it would make less sense to say "one million alpha radiations" -aliencam (talk) 00:21, 4 December 2011 (UTC)
- Matter and energy are not completely interconvertable, as there are many conservation rules that govern the process besides E=mc2. A photon cannot just turn into an alpha-- at best it would need to give an alpha/anti-alpha pair, and the odds of that are long indeed, and the energy needed is HUGE. On the flip side of this, baryons are conserved also, so in the absense of "antibaryons" they can't just disappear into energy. That means your alpha's kinetic energy is usable and convertable (that's how most radiothermal generators work, after all), but that's it. It does make a difference if the radiation is alpha, for after the alpha stops, it becomes helium and that's where most of THAT energy goes to. A child's helium balloon is actually just a bag of retired alpha particles once radiated from actinides in the Earth's crust-- their initial energy (3.727 Gev) is mostly still there, and still unconvertable to anything (unless you have a Wolf-Rayet star handy?). Only their intitial 5 MeV of kinetic energy (0.13%) was ever (in practicality) convertable to other forms of energy. And probably never converted to any mass!
And dja, please don't consider all forms of radiation equivalent. In biology they are not, as these conservation rules govern how they interact with matter, not their total energy. See the article on relative biological effectiveness, for many example of this-- alphas are 20 to 300 times worse than photons, even counting kinetic energy of alphas against total energy of photons. Finally, although in quantum mechanics all particles have wave properties and vice versa, which of these attributes become important depends on yet other rules. One of the reasons photons ultimately act more like fields than particles (expecially at low energies) is that they are massless (a huge impact on their energy/momentum relation, and thus wavelength). Another is that they are bosons (as electrons are not). Being a boson makes a difference even to complex particles, which is why helium-4 easily forms a superfluid, whereas helium-3 does only with great difficulty (and at temperatures far nearer to absolute zero). And so on. Why not actually read this article about alpha particles? You might learn something! SBHarris 02:29, 4 December 2011 (UTC)
- Matter and energy are not completely interconvertable, as there are many conservation rules that govern the process besides E=mc2. A photon cannot just turn into an alpha-- at best it would need to give an alpha/anti-alpha pair, and the odds of that are long indeed, and the energy needed is HUGE. On the flip side of this, baryons are conserved also, so in the absense of "antibaryons" they can't just disappear into energy. That means your alpha's kinetic energy is usable and convertable (that's how most radiothermal generators work, after all), but that's it. It does make a difference if the radiation is alpha, for after the alpha stops, it becomes helium and that's where most of THAT energy goes to. A child's helium balloon is actually just a bag of retired alpha particles once radiated from actinides in the Earth's crust-- their initial energy (3.727 Gev) is mostly still there, and still unconvertable to anything (unless you have a Wolf-Rayet star handy?). Only their intitial 5 MeV of kinetic energy (0.13%) was ever (in practicality) convertable to other forms of energy. And probably never converted to any mass!
In The Nuclear binding energy article it states that the semi-empirical binding energy formula takes into account that the n-p bond energy is greater than either the n-n or p-p bonds. Wouldn't this indicate that the alpha particle is probably made up of 2 bonded deuteron (1H2) particles?WFPM (talk) 21:54, 12 April 2013 (UTC)
See also
Needs a little trimming. All the best: Rich Farmbrough, 14:04, 25 May 2014 (UTC).
Symbol
The article currently states:
"If the ion gains electrons from its environment, the alpha particle can be written as a normal (electrically neutral) helium atom 4
2He."
This is unclear. How could the species still be an alpha particle if it has gained electrons to become an ordinary (neutral) helium atom?
—DIV (120.17.7.219 (talk) 12:48, 25 August 2017 (UTC))
- It is no longer an ion ... fixed. Vsmith (talk) 17:57, 25 August 2017 (UTC)
- Seems that this is all convention. Note that all our helium that comes out of the ground in natural gas originated as alpha particles, and got that name before it was known what they are. We could just as easily call the floating balloons alpha balloons, but that is not common. Once they slow down enough, and grab electrons off whatever is nearby, we call them helium. Gah4 (talk) 18:37, 24 November 2020 (UTC)
They then caused an electric spark inside the tube, which provided a shower of electrons that were taken up by the ions to form neutral atoms of a gas.
The article says: They then caused an electric spark inside the tube, which provided a shower of electrons that were taken up by the ions to form neutral atoms of a gas. This sounds a little strange to me. The alpha particles won't be a gas until they get electrons, which they likely will as soon as they hit the wall. As long as they don't go too far into the fall. Do they then stick? You can't get a spark through vacuum, but only through gas. It might be that heat is needed to get them off the wall, though. Gah4 (talk) 00:27, 2 October 2020 (UTC)
- I was about to say this, but it seems that I already did. Gah4 (talk) 18:32, 24 November 2020 (UTC)
- I guess the quoted sentence has since been removed. The spark bit in the article was still incorrect however.
- The Rutherford/Royds pair published two papers back to back. One was on the preparation and purification of the gas emitted by radium, lots of experimental details. The gist is that the carbon dioxide background was tough to get rid of. The second article was about the spectrum. With the gas in the tube, they created an electrical discharge and studied the emitted light to collect its spectral features. (I don't think He sticks to anything, so as soon as the alpha particle is neutralized its He gas). I added a ref to Pais "Inward Bound", who describes the experiment and result. Johnjbarton (talk) 02:22, 1 January 2024 (UTC)
Replacement of the Name section.
I rewrote the name section to give the origin of the name "alpha particle" and the connection to doubly ionized He atoms.
The previous section had no references and it has several claims about common usage (which probably cannot be verified unless some authority chose to say such). I suspect that when ever radioactivity is the source, the result is called "alpha particle" until the particle picks up two electrons and acts like a gas molecule, Helium. I doubt anyone calls the radiation product "doubly ionized Helium". On the other hand, if we start with Helium and ionize it, then yes we call it "doubly ionized Helium"; then it's not an alpha particle. The fact that these two products, from very different origins, have the same nucleons would not change the name used. I'll be on the look out for a reference to this effect. Johnjbarton (talk) 01:56, 1 January 2024 (UTC)