What isn't the distance between rays.

There are no such things as "rays" of light - that's a concept that people use in everyday speech that has no physical meaning. Instead think of light radiating from a point source as either:

a) electromagnetic waves that propagate much like waves across a pond. If you drop a stone in water the wave spreads outward and grows weaker as it progresses, or

b) packets of light energy called photons that spread ouward. If you stand near to the source the number of photons per second that enter your eye is enormous, but if you move away your eye intercepts fewer photons each second. The result is the object appers dimmer to us.

I'm not sure what you are asking, but I would say it depends on what two rays (if you can distinguish two) you're comparing and at which distance they are from the point source.