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What nuclear reactions are attributed to cosmic rays?

  1. Aug 22, 2008 #1

    I have a little bit of trouble writing an essay that relies on
    background knowledge of galactic cosmic rays. I found in textbooks
    solid writing about the history of discovery and composition, etc.
    I can not find simple exemplary nuclear reactions that happen in atmosphere or on Earth in general. Common carbon dating technique is
    based on one such reaction. That information is in the above link (scroll
    half way down). Another reaction that is there seems to be incomplete. Do you know any reactions that I can quote?
  2. jcsd
  3. Aug 22, 2008 #2
    The cosmic ray spectrum consists of all heavy ions up to Iron. So from Hydrogen to Iron, there is a fairly diffuse background of radiation that has a relatively small flux.

    So, these fully ionized cosmic rays (they are only the positively charge nucleus, their electrons have been stripped away) can interact through many mechanisms (nuclear and electromagnetic) with the molecules in the atmosphere. So there are many, many different reactions that can occur. Much too many to explicitly list. I would recommend taking a look around the net for "atmospheric cosmic ray showers" or "electromagnetic cascades" or "cosmic ray air shower" or other variations.
  4. Aug 22, 2008 #3


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    There are a number of reactions -


    Certainly charged nuclei (and protons), will ionize atoms, and occasionally will collide with or scatter with the nuclei of the gas molecules in the atmosphere.

    With collisions, there is the posibility of particle creation, much like one obtains in high energy particle accelerator or collider. In this case, matter-antimatter pairs are created. At some point, the antimatter finds its matter particle and there is an annihilation reactions.

    Another consequence of the particle collision is spallation - where nucleons, or groups of nucleons, are knocked out of the nucleus.

    This might be of interest -
    Ultrahigh Energy Cosmic Rays: The state of the art before the Auger Observatory
    Authors: Luis Anchordoqui, Thomas Paul, Stephen Reucroft, John Swain

    Here is a paper describing radiation in space.

    NASA Conference Publication 3360 · December 1997
    Shielding Strategies for Human Space Exploration
    Figure 1 shows tracks of various nuclei made in emulsions.
    Chapter 2 has some information on radiation and models.

    Edited by
    J. W. Wilson
    Langley Research Center · Hampton, Virginia

    J. Miller
    Lawrence Berkeley National Laboratory · Berkeley, California

    A. Konradi
    Lyndon B. Johnson Space Center · Houston, Texas

    F. A. Cucinotta
    Langley Research Center · Hampton, Virginia

    Proceedings of a workshop sponsored by the National Aeronautics and Space Administration and held at Lyndon B. Johnson Space Center, Houston, Texas
    December 6-8, 1995
    459 pages
    Last edited: Aug 22, 2008
  5. Aug 23, 2008 #4
    Yes yes WHERE are my professors! My former teacher of nuclear physics is nice man but he's not available, and these other's behave as if they don't believe in those "rays".

    I looked through so many articles and textbooks I had so there's plenty of content in general, but not the reactions probably because they are numerous. On this link there is a list of "cosmogenic radionuclides":
    they quoted this web site:
    http://www.icsu-scope.org/downloadpubs/scope50/chapter01.html [Broken]
    and the keyword for searching might be "nuclear chemistry".

    Cosmic rays appear to be highly important for discovery of particles and setting ground for nuclear physics, space climate, tests of relativity, galactic astronomy, cosmology - therefore I believe this topic should be rich in content.
    Last edited by a moderator: May 3, 2017
  6. Aug 23, 2008 #5


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    Well, that Wikipedia article answers some of your question - it shows the (p,n) reaction, the (n,p) reaction, and mentions spallation.

    Then there is particle production, which has a high threshold energy (~ 6 GeV, due to conservation of energy and momentum) in which p collides with p and produces a [itex]p, \bar{p}[/itex] pair. The anti-p subsequently annihiates with another p and produces a shower of pions, which decay to muons or gammas (depending on charge), and muons subsequently decay to electrons, neutrinos and anti-neutrinos.

    See also - http://www2.slac.stanford.edu/VVC/cosmicrays/


    Have fun!
  7. Sep 9, 2008 #6
    Cosmogenic 7Be is a natural tracer not altered by anthropogenic activities. Once produced, 7Be atoms are almost immediately absorbed onto aerosol particles. Aerosol particles are the most important reservoir of air pollutants,7Be can be used in tracking their atmospheric paths and fall-out.

    14N + p -> 7Be + 2 x 4He
    14N + n -> 7Be + 8Li

    16O + p -> 7Be + 10B
    16O + p -> 7Be + 7Li + 3He
    16O + n -> 7Be + 10Be
    16O + n -> 7Be + 6He + 4He

    Beryllium can be collected from the plants, soil or roof tops. It is produced mostly in the summer for some reason, allegedly thinning of tropopause. I don't know what that is, but I wondered if there is a link to noctilucent clouds.
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