Simplest solution is sparking the ARAYs with any conductor other than PSCN. When sparked with PSCN, ARAYs shoot a sort of "cleansing BRAY" that kills any BRAY particles in its way. If two (non-cleansing, ordinary) BRAY beams collide, they create a "lingering" BRAY particle at the intersection point. An ordinary BRAY stays for 30 frames, a "lingering" one stays for 1020 frames. (So it's really not lingering, it just takes longer to disappear; you have to shoot it with BRAY every 1000 frames or so to keep if from disappearing.)

There's something else though. Although it might look like it, BRAY beams shot in the same frame are not actually shot at the same time (unless they originate from the same particle of ARAY). One will be shot earlier, one will be shot later. The one that's been shot later stops when it collides with the one that's been shot earlier:

Unfortunately the order of shooting depends on something called [particle order], which in turn depends on the order in which you placed your ARAY (or any other) particles. Saving and opening the simulation makes life somewhat easier; doing that resets the particle order so that the left-most particle in the top-most row is the first, the one on its right is the second, etc. and after that comes the row of particles below them.