A spinal mount, the Anti-Particle Accelerator Weapon System, or A-PAWS, is massive in size, cost and energy requirements. Though technically minded sophonts have been researching antimatter for millennia, we have yet to field a missile or provide power through its use, but near the end of tech level 15 this new weapon systems has been designed, though not constructed.
The reason no polity has not made our latest and greatest dreadnought mounting A-PAWS may be due to its cost? Its mass? Or, even, its tremendous energy drain it will demand? One cannot say, though the technical achievements in its mere design are tremendous.
To successfully mount and fire the A-PAWS, an extremely massive amount of energy will be used in the formation and storage of antimatter. Heavier equipment will be called for by the weapon systems to handle the increased power drain. This severely hampers the ways A-PAWS may be used in arming vessels, and also supplies a plausible reason for their absence from naval architects design systems until now.
Though technically feasible, building an antimatter weapon at earlier tech levels would have lead to such a massive ground-based weapon that there would be no way to aim it, and the thought of constructing a naval vessel carrying this weapon is far beyond the scope of naval designers and engineers due to the expense in both monetary and energy requirements. Not to mention, the size of the vessel would rival that of a small moon.
Once those three issues are lessened to the point where designers can begin developing systems and vessels armed with A-PAWS, there is, of course, the issue of where this weapon system can be fired from. One cannot fire the A-PAWS when in an atmosphere of any type. Being near an atmosphere or within an interstellar or interplanetary gas or dust cloud would cause the same violent end. Firing an antimatter-based weapon through any form of matter — be it solid, liquid or gaseous — would react as the beam left the vacuum of the weapon's muzzle. In other words, a suicidal error!
History & Background (Dossier)
Thus, A-PAWS are only going to be used in ship-to-ship combat and orbital bombardment, once the starships leave the shipyards. Though limited in its usefulness, when A-PAWS hits its target, disregarding black globes, the target is vaporized. Black globes, of course, absorb the damage up to its capacitors maximum charge.
Planetary bombardment results in the equivalent of a large thermonuclear explosion at the point of impact. The atmosphere that the bolt of antimatter passed through, being vaporized to pure energy, would crack like thousands of lightning bolts. To fully strike at the planet, one must over come the atmosphere that surrounds it by stripping it away with each shot. Though, once the atmosphere has been removed, with continual bombardment, the planet itself may be reduced to the beginning of an asteroid belt.
With this form of devastation in the shape of a spinal mount, other fleets will mark the A-PAWS-armed vessel as a "Priority One!" target.
This weapon system is a form of nuclear warhead, as well.
References & Contributors (Sources)
Author's Note: This was pulled from an article in Journal of the Travellers Aid Society No. 20, though worded in a way that this weapon system was not canon per se, but left in the hands of the referee to add to his Traveller universe at his own discretion. I have marked this as canon, though, since it did come from a canon source.