Understanding Neutron Radiography

For photons:
I = I o e –μx t
For Neutron
I = I o e –Nσt = I o e –μ n
t
Eq.1
Eq.2
Where:
• I is the transmitted beam;
• I o is the incident beam;
• μ x is the linear attenuation coefficient for photons;
• t is the thickness of specimen in the beam path;
• N is the number of atoms per cubic centimeter;
• σ is the microscopic neutron cross section of the particular material or
isotope (a probability or effective area); and,
• μ n is the macroscopic cross section (μ n = Nσ).
Charlie Chong/ Fion Zhang