I’ve looked for a version of the double slit experiment in which the detector (of photo, electron, etc.) is also placed on the slit screen itself, the side facing the emitter. Thinking: As we know, the probability wave of a single emitted photon passes through both slits (assuming no measurement there) and then the photon is measured in a specific spot on the screen on the other side (as photons collect, an interference pattern emerges). The space between the slits (and above, etc.) must also be included in the probability set of the photon’s journey or impact point—ie is included in the wave function. In other words, presumably, not all photons register on the detector screen, some must be lost to areas outside the detector. Would measuring a case where the photon is measured hitting the screen instead of passing through the slit(s) disrupt the interference pattern of photons on the final detector screen (the one on the other side of the slits)? Thanks in advance…
$\begingroup$ physics.stackexchange.com/questions/675002/… $\endgroup$– PhysicsDaveNov 5, 2021 at 12:49
No, in principle detecting photons that would otherwise have hit the barrier, rather than passing through the slits in the barrier, should not affect the interference pattern.
Quantum mechanical explanations of the two slits experiment typically treat the barrier as something that blocks the propagation of the wave function everywhere apart from through the slits. Effectively it means that the barrier is assumed to be opaque, so it will either reflect or absorb particles that hit it.
The barrier could, for example, be a photographic film with two slits cut into it, which would show where particles had impinged upon it.