I'm going to assume that it shoots multiple beams, and you tune it so that they converge on a point. Anything on that exact point takes damage, and anything near it takes very minor "splash" damage. Blast radius would be a sort of seed shape.
'least, that's what I'd do with it.
2% of GameFAQs users have this in their signature. If you're one of the 98% that doesn't, copy and paste this into your signature.