A value of one is such that no particle can pass.
Larger particles cannot pass through until they have been chewed down to size.
In the above example, a particle can pass through two slits at the same time.
Small particles like this do not settle out and will pass right through filter paper.
The most common particle in the universe continuously passes through each of us.
Only the smallest particles can pass through the paper.
Those particles, all neutrinos of various kinds, pass through other matter almost without a trace.
This produces a current which indicates that a particle has passed through the chamber.
Uncharged particles, such as neutrinos, just pass through us without much effect.
Each panel acts as a position sensitive detector for charged particles passing through.