Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Deriving the Bateman equation of Nuclear Decay Chains

  1. Mar 13, 2007 #1
    1. The problem statement, all variables and given/known data

    Derive Bateman equation for a decay chain
    a->b->c->d where each decays with a given mean life let decay constant be L, where L=1/mean life
    Na(0)=No, Nb(0)=Nc(0)=Nd(0)=0

    2. Relevant equations

    Want to derive Nb(t)={(No)(La)/(Lb-La)}*{exp[-La*t]-exp[-Lb*t]}
    extend for Nc(t)

    3. The attempt at a solution



    this is a none homogenous differential equation. I can't find a way to solve it.


    I'm really not sure where to go from here.

    If anyone could lend a hand it would be greatly appreciated.
  2. jcsd
  3. Mar 14, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    Ok, so what you are really asking is how to solve y'(t)+L*y(t)=f(t). You know the homogenous solution is exp(-L*t). Guess the solution will be of the form y(t)=g(t)*exp(-L*t). Put this guess into your original equation and get:


    So g'(t)=exp(L*t)*f(t) and you can just integrate to get g(t).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook