#### Simulating light propagation in turbid media

Welcome to "*Multi-Scattering*" a freely accessible online software for the modeling of light propagation in scattering and absorbing media. Possible applications of the model are the prediction of photon transport in tissues, blood samples, clouds, smoke, fog, turbid liquids, spray systems, etc. As the simulations are run from a computer server at the Department of Physics at Lund University, any researcher can log in and use it freely without any programming skills or requirements for any software/hardware installations.

The simulation is based on the use of the Monte Carlo method, where billions of photon packets are being tracked through simulated cubic volumes using successive random samplings. The simulation is accelerated, here, by means of general-purpose computing on graphics processing units (GP-GPU). Each simulation is run using 3 computers, each containing 4 GPUs (Nvidia GeForce GTX 1080 Ti). Thus, a single simulation can be run from 12 GPUs, allowing unprecedented reduction of computational time where billion of photons are computed within a few seconds only for most case of scattering media.

Another feature of the software is the implementation of the Lorenz-Mie theory to generate the scattering phase functions from spherical particles, cells or droplets, when needed. The software also includes the simulation of image formation by inserting a virtual collecting lens and a detection matrix representing a camera objective and a sensor array respectively. The output results are also displayed by "

*Multi-Scattering*" and a few examples of results can be visualized from various default simualtions.