LAUSR

Abstract In this study photon distribution and their correlation with measured diffuse reflectance and transmittance from UHMWPE were investigated from 200 nm to 800 nm. The values of scattering coefficients μs, absorption coefficients μa in cm−1 for UHMWPE were extracted by using Kubelka Munk Model (KMM) from diffuse reflectance and transmittance measurements. It was found that both absorption and scattering coefficients has higher values in shorter wavelength regions. The void space in UHMWPE matrix, C=C poly-unsaturation and high values of refractive index mismatch, respectively were considered responsible for this behavior. In addition, the penetration depth δ was found higher in near IR region i.e. from 680 to 780 nm and it has peak value 75 ± 1.5 mm at 700 nm. The lowest values of μa i.e. 0.042 cm−1, forward directed scattering behavior of UHMWPE and almost constant values of μs in this region were the major responsible factors for larger penetration of incident photons. Furthermore, the accuracy of results was validated theoretically using Monte Carlo method while using extracted optical parameters as input for Monte Carlo code. It was found that experimental results were in good agreement with theoretical one. Also, distribution of photons for 300 nm and 800 nm were simulated and plotted as a function of their radial and depth positions which revealed the higher penetration depth for low energy photons i.e. up to 0.05 cm for 800 nm.