"Beamer" was the colloquial moniker in the Revelation Space universe for handheld energy weapons, usually one-handed, in the form of a pistol or similar handgun.
While dealing with the threat of the Sun Stealer to the Nostalgia for Infinity Ana Khouri visited the ship's weapon storage and Warchive to acquire some personal weapons for herself, Ilia Volyova and Pascale. For Pascale, she had the Warchive manufacture a smaller, compact "beamer" pistol, based on schematics available in its database.
Particle-beam pistols and handguns also had a larger counterpart in the form of particle-beam rifles, also powered by ammo-cells.
-"Now give me something a novice can use,' Khouri said, dithering in front of the warchive's dispensary. "I'm not talking about a toy, though -- it's got to have real stopping power."
-"Beam or projectile, madame?"
-"Make it a low-yield beam. We don't want Pascale putting holes in the hull."
When it was done -- as it was with the little pistol Khouri had imagined for Pascale -- the slot in the tabletop would whir open and the finished weapon would rise on a little felt-topped platter, gleaming with ultrasterility, still warm with the residual heat of its manufacture. She lifted Pascale's pistol, sighting along the barrel, feeling the balance, running through the beam-yield settings, accessed by a stud recessed into the grip.
Khouri threw her one of the lightweight guns; the needle-projectors she had found on the warchive's wall.
"Take this for Pascale," she said, throwing the low-yield beamer after it. Volyova caught both weapons expertly and quickly passed Pascale her own.
-"I'll... what is it I'm supposed to say at this point? Cover you?" Pascale had her low-yield beam gun out, without looking like she had much idea what to do with it.
-"Yes," Khouri said. "You cover me. That's a very good idea."
Pascale raised the beamer and blasted the whole assembly (...)
(Khouri) unsheathed the only weapon she now had left, the tiny, ineffectual needler she carried only because of the precision it allowed. She began to squirt it at the mass of rats while Pascale doused them with the beamer, which was hardly more suited to the task.
- excerpts from Revelation Space 
It was sometimes difficult to tell apart a beam-gun from a slug-gun:
With one smooth movement he drew the gun from his holster, giving Sylveste time enough to notice the bronze snake which spiralled around the barrel. The weapon's mode of killing was not at all obvious; it might have been a beam or projectile gun, but he had no doubts that he was comfortably within its lethal range. - excerpt from Revelation Space 
See also Edit
| Melee weapons | Whiphound | Crossbow | Clockwork gun |
Slug-gun | Submachine gun | Dart rifle | Electromagnetic needle-gun
"Beamer" pistol | Particle-beam rifle | Plasma rifle | Plasma bazooka
|Ouroborus-class Worm | Weevil-class War Robot | Whiphound|
|SPACECRAFT WEAPONRY AND DEFENCES|
| Magnetic railgun | Boser | Ack-am | Foam-phase Munition | Pin-head munitions |
Camouflaging screens | Hypometric weapon | Bladder-mine
|Cache Weapons | Solar Weapon|