Chapter 4: Interaction of Radiation with Matter – Interaction of Photons with Matter
Linear attenuation coefficients, and Atomic attenuation coefficient
NPRE 441, Principles of Radiation Protection, Spring 2020 Chapter 4: Interaction of Radiation with Matter – Interaction of Photons with Matter Linear Attenuation Coefficients
F Monochromatic photons are attenuated exponentially in a uniform target. F The number of photons in a pencil beam interact within a small distance dx is
dN = -µNdx
where µ is the linear attenuation coefficient and the solution to the above differential equation is
-µx N(x) = N0e
exp(-µx) is simply the probability of a photon penetrating a distance x without interaction.
NPRE 441, Principles of Radiation Protection, Spring 2020 Chapter 4: Interaction of Radiation with Matter – Interaction of Photons with Matter Linear Attenuation Coefficients
F Linear attenuation coefficient is measured using the following setup