Particle beams are weapons that accelerate atomic or sub-atomic particles to within a few percent of the speed of light and then direct them at a target through a series of electrostatic (not electromagnetic) focusing/acceleration arrays. Essentially they are very similar to rail guns or electromagnetic mass drivers except that they use electrostatic forces rather than electromagnetic, and they are firing beams of particles rather than solid slugs or projectiles.
Particle beam weapons faced many of the same problems as laser weapons in the early days of directed energy weapon development, and most of the issues that solved lasers for practical application also made particle beam weapons a reality as well. In practical application, particle beams are actually better weapons for use in enclosed and pressurized, self contained environments since the damage caused by a particle beam weapon is very similar to the damage caused by a ballistic projectile. The added benefit being that particle beams have a nearly instant hit (since the beam travels near the speed of light there is no need to ‘lead’ your target in order to compensate for the travel time of the projectile) and there is no need to carry extra ammunition for a particle beam since the newest weapons distil the particles they need to fire out of normal, breathable atmosphere (space based particle beam weapons however, DO need a ready supply of particles and thusly, a reservoir of gas or atmosphere to consume over the normal process of firing).
Effective Range: In an atmosphere, 1 to 2 miles. In a vacuum, 100 to 500 miles.
Maximum Range: In an atmosphere, 5 to 10 miles, In a vacuum, 1000 to 5000 miles.
Payload: Effectively unlimited, assuming a ready supply of gas or particles and a fusion power supply.
Weapon Class: C
Particle beam weapons are not illegal to use in confined air spaces like lasers are, so they are technically not controlled items. However, their cost makes them difficult for the average person to afford and as such they are still relatively uncommon.