Dear All, I have a question on the double slit experiment. From the references I've read so far, they are focusing on the results of the detector AFTER the 2 slits. Let's say when photons are fired, how many % actually pass through the slits and get detected at the end? Would some (and how many) end up colliding at the barrier (marked in red) where the slits are, and would this result change if that barrier is a "detector"? If so, what pattern does it show there?