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Ionization radiation vs ordinary ionization/electrical breakdown

  1. Feb 9, 2014 #1
    Ionization radiation vs "ordinary ionization/electrical breakdown"

    Hi, I hope I get understood correctly, my question is seemingly simple:

    Why is ionization radiation( energetic rays like gamma rays) dangerous and vastly different than say any common everyday ionization from a normal electrical breakdown or electric discharges like finger tip discharge to a van de graaf , or corona discharge/ glow discharge? in both cases you have a a removal of electrons from atoms....

    Despite this, all I find about the reason of the danger is that ionization radiation removes electrons from atoms. On the other hand you got electrons removed from atoms in all ordinary electrical discharges so what is the difference? I have searched and read everywhere w/o results.

    Thanks
     
    Last edited: Feb 9, 2014
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  3. Feb 9, 2014 #2

    Astronuc

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    An electrical discharge could prove fatal, just as a certain level of ionizing radiation could prove fatal or make one ill.

    One would have to be in close proximity to a high voltage discharge, whereas one can be at some distance from the source of ionizing radiation.

    Another difference is takes a lot less high energy radiation to cause ionization than for an electrical discharge, which would require a high current.

    Furthermore, ionizing radiation like gamma rays is high penetrating so that it can pass into a body.

    If one ingests a source of ionizing radiation, then irradiation comes from within, and can persist as long as the radionuclides are within the body.

    Normally, one does not make contact with a high voltage or ionizing radiation source.

    Finally, a high voltage can be switched off. Radionuclides (and their radiation) cannot be turned off.
     
  4. Feb 10, 2014 #3
    Thanks Astronuc,
    I was thinking of the specific action of the removal of electrons from atoms in an Ionization Radiation,
    Is the removal of electrons, or the process of removal of electrons itself in Ion.Rad. different from ordinary ionization like glow/arc/corona etc discharge? Because, at the end , the energy level that was needed to remove an electron was reached in either method if I understand this correctly?
     
  5. Feb 10, 2014 #4

    Astronuc

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    Electrical discharges generally involve the outermost (valence) electrons. Ionizing radiation can interact (knock out) electrons from the inner most shells via photoelectric effect or Compton scattering, and that is how X-rays are produced. High voltage discharges can produce energetic electrons comparable to low level radiation.

    For gamma-rays above 1.022 MeV, pair production is possible. In pair production the energy of the gamma is transformed into a positron-electron pair.
     
  6. Feb 10, 2014 #5
    Thanks, alright, so if I understand this correctly, the main difference of danger between ion. radi. and ordinary radiation is the big and unmatched magnitude of atoms whos electrons are removed due to the unshieldable property of these energetic rays that can penetrate deep inside a body tissue? And thus this radiation can basically unhindered remove electrons from a large number of atoms in your body, whereas any other typical (non lethal)ionization discharge only remove electrons from the outer surface only and cannot penetrate and affect an armada of atoms like a gamma ray does?

    Thanks
     
  7. Feb 10, 2014 #6

    Astronuc

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    Gamma radiation would penetrate the body, and rather than remove electrons from the body, it simply ionizes atoms in situ. That ionization destroys cells by producing free radicals and altering DNA, proteins, hormones and other complex molecules.

    An electrical discharge would burn the skin or damage nerves and muscles, if the current was large enough.
     
  8. Feb 10, 2014 #7

    Choppy

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    Just to add to what Astronuc has said, you have to think about the energies involved and how their pattern of dispersion.

    An electrical current travelling through the body is going to follow a path of least resistance. It may branch out of course, but it might be helpful to think if it like a single track that that passes through the body. Along that track you'll get all sorts of damage. But the intensity will be so high the primary concerns are heat damage and the effects of the current density on all of the systems that rely on differences in electrical potential to function (nerve cells might be an example). The energies of the individual electrons are likely to be very small, and so they won't move very far (less than 1 um) off of their track. The cells immediately in the line of this path are generally destroyed.

    With ionizing radiation you generally don't have the intensity to worry about factors such as heating. In radiation therapy we typically deliver doses on the order of 2 Gy or 2 joules per kg. In water that works out to a temperature change of ~ 5E-4 degrees C, so "burning" anything isn't much of a concern. But when the photons interact with something in the body, they create an energetic electron track which in some cases can stretch through a tortuous path over several cm or more (depending on the energy of the radiation in question). As those electrons travel through cells they generate all sorts of free radicals which then interact with and damage cell components - the most sensitive of which is DNA. This of course is happening all the time due to background radiation, and your cells are constantly repairing the damage. But not all damage is repaired. Sometimes the cell is a write off and commits a kind of cellular suicide (apoptosis). Sometimes it just loses the ability to reproduce itself (which is quite helpful in treating cancer). Sometimes the damage doesn't really do much of anything and simply gets passed on to the next generation.
     
  9. Feb 11, 2014 #8
    Thank you Choppy and Astro for your answers.
    hmm about the fre radicals production, I am not sure if I am understanding it fully, Il see if I can understand it more.
     
  10. Feb 11, 2014 #9

    Astronuc

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    Free radicals are anions such as OH- or O2-, which are formed through radiolysis (ionization) of water.

    http://en.wikipedia.org/wiki/Radical_(chemistry [Broken])
     
    Last edited by a moderator: May 6, 2017
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