Atomic beam is special case of particle beam

Particle beam

A particle beam is a stream of charged or neutral particles which may be directed by magnets and focused by electrostatic lenses, although they may also be self-focusing ....

; it is the collimated flux (beam) of neutral atoms.
The imaging systems using the slow atomic beams can use the Fresnel zone plate (Fresnel diffraction lens) of a Fresnel diffraction mirror as focusing element. The imaging system with atomic beam could provide the sub-micrometre resolution.

See pics of the Atomic beam laboratory at http://cc.ysu.edu/physics-astro/Atomic.htm