From c049016e24fc38ac35c18282a898e1df18d94d57 Mon Sep 17 00:00:00 2001 From: Paul Romano Date: Tue, 24 Jul 2012 17:43:07 -0400 Subject: [PATCH] Added clarification in doc section on elastic scattering regarding scattering cosine in lab. --- docs/source/methods/physics.rst | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/docs/source/methods/physics.rst b/docs/source/methods/physics.rst index 13ce2c593b..763a4152ea 100644 --- a/docs/source/methods/physics.rst +++ b/docs/source/methods/physics.rst @@ -137,6 +137,11 @@ scattering cosine in the lab system can be calculated as \mu_{lab} = \frac{1 + A\mu}{\sqrt{A^2 + 2A\mu + 1}}. +However, this formula is only valid if the target was at rest. When the target +nucleus does have thermal motion, the cosine of the scattering angle can be +determined by simply taking the dot product of the neutron's initial and final +direction in the lab system. + .. _freegas: ------------------------------------------