deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index 01fdfba..7e7c7cd 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
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I=I_0 \exp(- \gamma r)  \label{eq:opticalIntensity}  \end{equation}  where $I_0=\frac{1}{S}\frac{d E}{dt}$ the incident intensity distribution at the surface (by neglecting the (the  reflection on the black mat medium) medium being neglected)  and $\gamma$ the absorption coefficient of the medium. !!!We measured the fraction of light which go through different thicknesses of the medium with a laser beam power measurement device (): it indicated that $\gamma \approx$ ??? m$^{-1}$ in our sample,!!! meaning that most of the radiation is absorbed in the first hundred of micrometers.  %Even if the sample is mainlyeFor low concentration medium, $\gamma$ is hard to calculate in our case, as the sample is composed of different materials, but the graphite, even in low concentration, absorbate much more than other components, so we can approximate $\gamma \approx \gamma_{graphite}$. For graphite particles of 1.85 $\mu$m at a concentration of 10 g.L$^{-1}$, the order of magnitude of $\gamma$ is 10$^4$ m$^{-1}$, meaning that most of the radiation is absorbed in the first hundred of micrometers of sample. 
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