Photon Penetration Depth: 2D Reactor Cross-Section

This is the 2D counterpart to the rotatable 3D reactor bank, and it is not a projection of that scene — it is an independently computed radiative-transfer model. A ring of sixteen discrete LED point sources illuminates each tube's circular cross-section, and every point inside is lit by the real superposition of Beer-Lambert attenuation from all sixteen, not by a shortcut assuming the light comes only from the nearest wall point. Catalyst molecules diffuse through this field as genuine 2D Brownian walkers, accumulating photochemical dose until they turn over and re-enter circulation — a direct model of how a flowing reactor keeps converting substrate. A live depth-profile chart plots this computed field's azimuthal average against the idealized 1D Beer-Lambert curve so you can see precisely where the simple textbook formula holds and where the full 2D field diverges from it, especially in the weakly-absorbing, thin-tube regime where illumination turns out to be far more uniform than the 1D shortcut implies.