# Does a parabolic diffuse surface reflect more light than a flat, rectangular surface in 2D (see figure)?

Which surface reflects more light into the black collecting surface, considering both the light collecting surfaces have the same length? Is there an equation that could help me determine this? I'm not an optics expert, I work in radiation detection (I'm working on a scintillator, and I'm trying to optimize geometry, but I'm struggling with some stuff).

• What's the source of light? If the incoming light beams are all roughly parallel this has some implications regarding the angle of incidence on the reflective surface. What materials are involved in constructing the surfaces? What's the wave length of the radiation? – R. Romero Nov 21 at 20:04
• @R.Romero Since the material is a scintillator, the light source is assumed to be randomly distributed all over the geometry (inside of it) – Betsy Nov 21 at 20:23
• @CuriousOne Is there an equation that gives me "amount of light collected"? I'm trying to write a code that models the parabolic surface coordinates (also the box), and then i would reflect light off the diffuse surfaces and calculate how much reaches the collecting surface. I have found equations providing reflectance, but not sure how to calcualte "amount" or intensity of light collected. – Betsy Nov 21 at 20:38