X-ray absorption & fluorescence

X-ray Absorption Information (11BM page) http://11bm.xor.aps.anl.gov/absorption.html

Absorption Length

Alternatively Attenuation Length is defined as the distance into a material where the x-ray beam intensity has decreased to 1 / e, or about 63% of the incident beam. The X-ray beam intensity at depth x into a material is calculated by Beer-Lambert law:

<math>

\operatorname{erfc}(x) =
\frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt =
\frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}}

</math>

I(x) = e^(-x/lambda)

ln(1/e) = ln(e ^-x/lambda)

1 = x/Lambda

1/lamda = x

1/mu = x

Links

• Absorb: compute X-ray absorption for powder XRD capillary samples (11BM page)

• MuCal: calculate X-ray absorption, fluorescence and more (by C. Segre @ IIT/ANL)