The invention comprises an alignment guide apparatus and a method of use thereof for aligning an imaging beam, longitudinally passing through an exit nozzle of an imaging system, to an imaging zone of a sample, includes the steps of: (1) providing an alignment guide, the alignment guide comprising: (a) a guide wall at least partially circumferentially enclosing an aperture, (b) a first laser element connected to the guide wall, and (c) a second laser element connected to the guide wall； (2) inserting the exit nozzle of the imaging system into the aperture； (3) projecting a first line from the first laser element onto the sample； (4) projecting a second line from the second laser element onto the sample； and (5) moving the sample relative to the exit nozzle of the imaging system to position an intersection of the first line and the second line at the imaging zone to align the imaging beam to the imaging zone.
