1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Creation of heavy elements: r and s process

  1. May 25, 2005 #1
    Hi, i'm studying my astronomy course at the moment and i have question about the r- and s-process. As I understand it, in the r-process, the time between capturing two neutrons is shorter than the averge beta decay half life, right? So i'm guessing there have to be a lot of neutrons around for the r process to take place. But where do all these neutrons come from?
  2. jcsd
  3. May 25, 2005 #2


    User Avatar
    Science Advisor

    It is mostly ionized H atoms, simply protons, among free electrons (=plasma) that gets the stars going in the core. See mainly pages 3-5 of this link:

    http://www.genesismission.org/educate/scimodule/SunandSolar/Final Linked SSW/6AppendicesCari/a.pdf
  4. May 29, 2005 #3


    User Avatar

    Staff: Mentor

    Neutrons can come from certain fusion reactions of light isotopes, and from spallation reactions in the heavier nuclides.

    See also - https://www.physicsforums.com/showpost.php?p=506354&postcount=7, which mentions reactions concerning production of superheavy elements.
    Last edited: May 29, 2005
  5. May 29, 2005 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Welcome to Physics Forums, Gideon!

    Others have already answered your question, in one sense; perhaps (however) you meant something like 'in what environments are such floods of neutrons likely to occur?'

    Supernovae, of the core collapse kind - can you now find out why such environments are expected to be so 'neutron-rich'?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Creation of heavy elements: r and s process