- #1
rpp
- 106
- 71
I am looking at the average lethargy gain of a neutron when colliding with a moderator, which is often referred to with the greek letter "xi" (see for example, Duderstadt and Hamilton page 324).
There is a general equation for calculating ##\xi##,
##\xi = 1 + \frac{\alpha}{1-\alpha} \ln \alpha##
And a table showing values of ##\xi## for several moderators.
I can successfully reproduce the value of ##\xi## for all of the single isotope moderators, but I cannot figure out how to calculate ##\xi## for compounds such as H2O and D2O.
For example, ##\xi## is: 1 for H, 0.12 for O, and 0.92 for H2O.
Any ideas?
There is a general equation for calculating ##\xi##,
##\xi = 1 + \frac{\alpha}{1-\alpha} \ln \alpha##
And a table showing values of ##\xi## for several moderators.
I can successfully reproduce the value of ##\xi## for all of the single isotope moderators, but I cannot figure out how to calculate ##\xi## for compounds such as H2O and D2O.
For example, ##\xi## is: 1 for H, 0.12 for O, and 0.92 for H2O.
Any ideas?