What I'd like to know about the two-slit experiment is how much apart those slits are from each other, and where is the photon actually targeted at? Do they aim

What I'd like to know about the two-slit experiment is how much apart those slits are from each other, and where is the photon actually targeted at? Do they aim at the middle or what? Edit: After thinking a little bit, they just shoot them at random directions so it's like sending photons in serial instead of parallel, but in serial mode the photons shouldn't interfere.