Alpha Particles in Closed Box

  1. Ok, so I am currently building a cloud chamber for a major presentation in the area of Thermodynamics (or Energy and Temperature) and i've been thinking quite a bit about this theory....and i could be don't tell me off about it....

    So the general physics of a cloud chamber, Isopropyl evaporates and moves down the chamber where it is met by the cold dry ice and it supersaturates and produces a cloud (per say)....high energy particles passes through this cloud and due to their ionisation energies they leave a trail in it's path....

    Now specifically i'm looking at alpha particles, 2 protons, 2 neutrons and no electrons (as opposed to it's Helium counterpart which has electrons), alpha particles technically do have mass and just like any other particle that has a mass should be influenced by outside energies (my assumption)....say for example an alpha particle in a vacuum box with no resistance to air, elastic will have a fixed energy (or so i'd assume)....but what if this box was to be heated....would they gain energy? Would they gain extra velocity? Would they obey the standard Boltzmann Energy equation? Or would they just decay in their already known lifetime?

    It's a really stupid question that i'm somewhat unable to ask anyone else without sounding silly....and it could be absolutely wrong....i'm trying to incorporate the cloud chamber into a thermodynamics aspect of the show and i don't see how....
  2. jcsd
  3. mfb

    Staff: Mentor

    Alpha particles at which energy? They usually come from nuclear reactions and have an energy of ~MeV. They are way quicker than your gas and won't be influenced by its temperature (~40 meV). Before they reach thermal energy, they capture electrons and stop being charged.

    Alpha particles are stable (assuming no proton decay, but that would have a timescale of >1030 years).
  4. I'm not talking about any specific energies at which they are released by, could be any energy, my logic is if these alpha particles were in a box from which they could maintain whatever energy they were released with and the box was heated up uniformly (to which the alpha particles could not escape) would they gain energy from that, there are no electrons in this's a vacuum free from air resistance or anything that would lower the energy of the alpha particles....

    But then i was thinking as i walked home there....the alpha particles don't have electrons, generally when anything is given energy up it's the electrons that react in a form of a release of a photon in the form of Planck's energy equation [itex]E=\hbar ω[/itex]....since alpha particles don't have electrons, they might not be affected....i still think all particles should be subject to energy changes when the temperature changes....isn't that how they simulated the Bose-Einstein effect of bosons in the lowest possible cooling them down to the Bose critical temperature to lower the uncertainty of energy of the boson in that state....i could be completely wrong....
    Last edited: Nov 16, 2012
  5. mfb

    Staff: Mentor

    Low-energetic alpha particles will capture electrons quickly, and you get regular helium atoms. Their energy depends on the temperature, but they are not visible in your cloud chamber anyway.

    You cannot build a cloud chamber without electrons.

    To get thermal, ionized alpha particles, you need a very hot plasma (something like 100 000 Kelvin) - and even there, you need electrons or the plasma will fly apart. An extremely low density in an extremely good vacuum and a very short timescale might work, too. Nothing you can reproduce with your experiments, however.
  6. Oh I know that, I wasn't talking about the physics of the cloud chamber itself, just a hypothetical scenario to feed my curiosity if they could ever be affected by temperature....ironically this was my first post and thread....I can see this place as a great way for physicists to ask questions
  7. Well the elastic walls should be vibrating due to the temperature, so it would gain energy every time it hits the walls, presuming it bounces off. But temperature is about average particle energy, so I'm really not sure if you can apply it to a single particle.
  8. I was talking about a box of alpha particles, not just one, but yes, that's what the physics in my head was saying, the energy would rise, the standard physics is the energy of a system is proportional to the temperature of the system, but yes....thanks so much for the help here!
  9. mfb

    Staff: Mentor

    Solid walls have electrons, and the alpha particles would steal them. Magnetic walls could work, but the whole concept is very hypothetical. It is no problem to assign a temperature to a collection of (thermalized) alpha particles, and their velocity would depend on their temperature.
  10. As I said the theory was a hypothetical scenario, it was negating collisions, electron capture or any other advance physics that might alter the outcome of the alpha particle....but I'm not trying to prove the ability to trap an alpha particle with my's only the temperature energy theory I'm interested in...
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