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Author Topic: Are new hydrogen atoms created in a nuclear explosion, and could we detect them?  (Read 1453 times)

Offline dhjdhj

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I attended a conference last Saturday in which we were shown the proposals for a new super hadron collider not far from the current LHC and it made me wonder if a controlled nuclear fission explosion could produce the energy and conditions to actually create new hydrogen atoms and if so could we study them. In particular how they form. Given that we can test weapons safely underground could it be possible to build such test facility to compete both in terms of finance and usefulness to the very LHC?
« Last Edit: 21/02/2016 22:21:25 by chris »


 

Offline evan_au

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Quote from: dhjdhj
create new hydrogen atoms and if so could we study them?
Why would you go to so much trouble to create hydrogen, when you can easily make hydrogen by passing electricity through water? This is an experiment that can be done at home, or in a science lab.

Studying the properties of hydrogen is the subject of chemistry, not high-energy particle physics.

The LHC buys its hydrogen in small cylinders from a commercial gas supplier. The LHC doesn't use very much hydrogen.

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if a controlled nuclear fission explosion could produce the energy and conditions to actually create new hydrogen atoms?
No.

A hydrogen atom consists of a proton and an electron.
  • The mass-energy of a proton is: 938 MeV/c2
  • The mass-energy of an electron is: 0.51 MeV/c2
  • Plus a little electrostatic attraction: 0.000013 MeV (enough for an ultraviolet photon)
A typical reaction used in a nuclear fission bomb is:
n + 235U → 141Ba + 92Kr + 3n + 202 MeV

This is not enough energy to "create" a proton, let alone a Hydrogen atom.

And you can't combine the energy of multiple nuclei to form an electron, because this fission energy is carried away as kinetic energy of the reaction products, a rather low grade of energy. Most of the energy ultimately appears as heat.

There is another way that you can "create" a hydrogen atom in a fission explosion: from the decay of the neutrons:
n → p+ + e- + v + 0.7 MeV
However, these neutrons tend to leave the explosion at fairly high velocity, and are far away when they finally decay, about 15 minutes later (on average). The energy released in the neutron decay means that the proton & electron fly apart, not leaving a hydrogen atom.

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if so could we study them... such test facility to compete both in terms of finance and usefulness to the very LHC?
No.
The detectors used at the LHC are massive machines, very delicate, and costing billions of dollars. You do not want to place these anywhere near a nuclear explosion.

The debris from a nuclear explosion is emitted with a wide variety of energies. However, the LHC allows quite accurate control of the energy of the protons involved in a collision. Tight control of the energy of the incoming protons, and accurate measurement of the energy of the debris from the collision is important if you are going to discover a Higgs Boson with an energy of 125000 MeV/c2 (which, by the way, is far higher than the energy you can get out of nuclear fission).

You also need to get a large enough statistical sample to make accurate estimates; the LHC detectors run about 25 million experiments per second, for 7 hours at a time, before recharging the LHC for another experimental run. You can only run one underground nuclear explosion per month.

Underground nuclear explosions are  banned for good reasons - they are one way for nations to design, test and maintain a nuclear arsenal (as North Korea seems to be doing at present). 
« Last Edit: 21/02/2016 20:43:13 by evan_au »
 
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Offline dhjdhj

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Thanks Ewan for the explanation as to why it wouldn't work, although I wasn't suggesting we make commercial hydrogen that way,just whether it was possible to use an explosion to create a atom from scratch. With your explanation I am happy to concede it would not be possible.
 

Offline chris

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Really good answer, Evan; I learned a lot from that.
 

Offline evan_au

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Quote from: evan_au
The LHC buys its hydrogen in small cylinders from a commercial gas supplier. The LHC doesn't use very much hydrogen.
Yesterday I saw the actual cylinder that supplied much of the hydrogen for the LHC from Spring 2012; many of the Higgs Bosons discovered at CERN that year were produced by colliding protons from this slim bottle (about 1 meter high).

It is part of an exhibition at the Powerhouse Museum in Sydney.
Fortunately, I arrived at just the right time, and we were shown around by a physicist who had just completed his Phd at CERN.
 

Offline Blame

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Yes and Yes.

Fission is going to produce neutrons which each decay into a proton and an electron. A proton plus an electron is a hydrogen atom even if the electron's actual location is problematic. Atoms are often letting their electrons wonder off and that doesn't stop them being called atoms.

The neutrons are easily detected in controlled fission (as in a power station).   
« Last Edit: 14/08/2016 09:48:18 by Blame »
 

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