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Particle Accelerators and a 22 caliber bullet.

  1. Nov 24, 2005 #1
    I’m trying to help put the energies of particle accelerators say the Fermilab Tevatron accelerator into layman’s perspective. Now if we were to scale up the energy put into say a proton and scale that up to a 22 caliber bullet, how much more energy would it require?
    Also put you answer in perspective with something like “it’s like putting the energy of the space shuttle launch into a 22 caliber bullet”
    Assume the 40 grain bullet to 2000 fps (rifle).
    Last edited: Nov 24, 2005
  2. jcsd
  3. Nov 26, 2005 #2


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    Lets take an energy of TeV (1 x 1012 ev, or 1.6022 × 10-7 J) for a proton of rest mass 1.6726 x 10-27 kg or rest mass-energy of 938.272 MeV, gives an specific energy of
    9.579 x 1019J/kg (on the basis of rest mass). Remember that mass increases with speed.
    Speaking of speed, a 1 TeV proton has speed about 0.9995 c, or 2.998 x 108 m/s >> 2200 ft/s (670 m/s).

    The bullet moving at 2200 ft/s (670 m/s) has a specific kinetic energy of v2/2 = 224450 J/kg which <<< 9.579 x 1019J/kg.

    On an energy basis though the bullet has greater kinetic energy - 584 J (based on 40 grains/2.6 g) vs. 1.6022 × 10-7 J. On the other hand, one only needs to accelerate 6.1 x 10-19 kg of protons to 1 TeV to obtain the some KE of 584 J.

    As for the Shuttle - the 3 SSME's have a thrust of 5.3 MN and let's say that thrust is applied over 200 km, which gives an energy of 1.06 x 1012J (I have excluded contribution of SRB's). Putting this into a 0.0026 kg bullet gives a specific energy of 4.077 x 14 J/kg, which is still 5 orders of magnitude less than the specific energy achieved by a 1 TeV proton.

    This may help to put energy in perspective.



    Also putting it another way using the equivalence of 11605 eV/K, a 1 TeV proton has a temperature of 11.605 x 1015 K, i.e. it is extremely hot!!! Compare this with about 3300 K in the SSME combustion chamber.
  4. Nov 26, 2005 #3
    That sounds all fine Astronuc but the average Joe on the street won't get it. How about putting it this way.

    The amount of energy put into a particle in the Tevatron accelerator is like putting the energy of X Hiroshima bomb(s) into a 22 caliber bullet.

    Te average Joe is familiar with both a bullet and the Hiroshima bomb but not with terms like, protons, rest mass, joules etc.
  5. Nov 26, 2005 #4


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    from http://en.wikipedia.org/wiki/Little_Boy

    Putting the equivalent energy in a 0.0026 kg bullet (40 grain (2.6 g), 22 caliber) would give 9.8 x 1015 J/kg

    And a 1 TeV proton has specific energy of 9.579 x 1019 J/kg,

    so a 1 TeV proton has the equivalent energy of putting 9775 Little Boy's (bomb dropped on Hiroshima) in a 22 (40 grain) bullet, or one could round it about 10,000 Hiroshima bombs.
    Last edited: Nov 26, 2005
  6. Nov 26, 2005 #5

    what prompted me to pose this question was a popular media news clip a few years back where they stated a extreme cosmic ray or was it a gamma ray burst:? had an estimate energy equal to an 40 mph or so "fast ball" (baseball). I felt they did an injustice in their comparison for a layman to grasp the magnitude of energy inputted into the particle. Now if my memory is correct they also stated that it was about 50 million times more energy than the Tevatron accelerator.

    Now imagine trying to explain that!
  7. Nov 26, 2005 #6
    please check your calculations

    1 grain = 0.065 grams
    40 grains = 2.6 grams
  8. Nov 26, 2005 #7


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    I corrected the typo. I was originally writing 2.6 grams, then intended to write 0.0026 kg, but instead wrote 0.0026 gram.
  9. Nov 26, 2005 #8


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    Yah, those are cosmic particles that are rather curious because their energies dance around this GZK limit. We aren't suppose to be observing such high energy particles unless their is a high energy source nearby (which there isn't unless we're REALLY missing something about our solar system...). I did a quick and crude calculation based on the speed those particles go and if you got a kg of material and you wanted to accelerate it to the speeds those protons come at... it would take something like 90,000,000,000 Tsar hydrogen bombs (Russian thermonuclear weapon, largest ever built with an energy equivalent to 50 megatons of tnt)
  10. Nov 27, 2005 #9


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    I'm not sure scaling this way is meaningful or impressive. For example, the electrons in a TV picture tube travel at about a tenth the speed of light. If bullets went that fast, they would each have as much energy as a bomb.

    Re the Tevatron, your average Joe or Jill understands neither how incredibly fast nor how incredibly tiny the protons are. But consider this: The tevatron can accelerate 10^13 protons to 1 TeV. That is an energy of a million joules circulating in the vacuum chamber. A million joules is the amount of energy it takes to bring a 3000 pound car to the top of a 30 story building. Think of it: If you shove this car off the building, the amount of energy it has when it hits the ground is the same as the amount of energy stored in this skinny 6km vacuum tube. Let it out all at once and this energy gets deposited in 21 millionths of a second. If it happens in an unprotected area, it's quite a catastrophe.
  11. Nov 27, 2005 #10
    I don't read up on it much but I suspect some as of yet undetectable particles are involved, perhaps having to do with dark matter? well that's a different discussion.

  12. Nov 27, 2005 #11
    Well, how much of a bomb? I'd bet an average Joe or Jill would gain some perspective from such an comparison that may be indeed impressive into the nether world of the subatomic. What if that was your task; to try to explain it to your average Joe or Jill or a class of middle school students for that matter.

    Have you considered such scientists as Brian Greene, Michio Kaku or Carl Sagan who have to some degree able to explain to some deep scientific concepts to the common audience?

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