I like this design. Visually, in terms of the design, I have no complaints. It's great.
Though, in terms of practically. I have to say that the "active heat dissipation mode" doesn't seem to do anything, since it doesn't alter the surface area of the weapon at all. Perhaps if only the sleeves of the "fins" leaving the containment components in place it would seem practical. (Though considering this is sci-fi, you don't have to do it. You can always invent technobabble) I also don't think "Gatling" is a good descriptor of it, since each individual "fin" doesn't look like it's capable of firing independently.
im seeing this as probably a plasma beam or something along those lines. as the energy builds it opens up and when it finishes "chargeing" it closes and focuses the energy to a single point just before fired as a beam for 1-10 seconds depending on the class of ship its fit to. now the counter would be a EMP to desable the plasma containment thus destroying the gun and posably a bit of damage or you could damage/destroy one of the lower prongs to have the plasma disscharge into the hull...whelp i have a "Ecperimental Weapon" for the large med tech faction now '3' not 100% on the spelling but meh
I've always longed for something in a space sim game akin to the Gravity Wave Cannon in Martian Successor Nadesico. Sorry if this seems like a random tangent, I was simply reminded by the use of the accelerator foils.