An Experimental Scattering Matrix for Lunar Regolith Simulant JSC-1A at Visible Wavelengths

We present the experimental scattering matrix as a function of the scattering angle of the lunar soil simulant JSC-1A. The measurements were performed at 488, 520, and 647 nm, covering the range of scattering angles from 3^\circ to 177^\circ . The effect of sub-micron-sized particles on the measured phase function and degree of linear polarization has been studied. After removing particles smaller than a 1 μm radius, the forward-scattering peak becomes steeper. Furthermore, the maximum of the degree of linear polarization increases, moving toward smaller scattering angles. Interestingly, the negative branch in the backward direction disappears as the small particles are removed from the sample. Because multiple scattering calculations with polarization included require single scattering matrices throughout the scattering range (from 0^\circ to 180^\circ ), we computed the corresponding synthetic scattering matrix through an extrapolation method, considering theoretical boundary conditions. From the extrapolated results, the asymmetry parameter g and the back-scattering linear depolarization factor {δ }<SUB>L</SUB> were computed.