Patent ID: 8773661

Claim:
A cytometry system for analyzing particles suspended in a fluid stream, the system comprising: a light source for directing light through a sensing region in the fluid stream; an objective positioned to receive light from the sensing region of the fluid stream; a lens aligned with the objective; a field stop having a shaped aperture comprising a relatively small center portion, and relatively large first and second end portions, wherein the lens is positioned to focus the received light onto the shaped aperture; a light detector system comprising a center light detector operable to receive light that is focused by the lens on the relatively small center portion of the aperture, and further comprising first and second peripheral light detectors; a first light deflector positioned over the relatively large first end portion of the shaped aperture and operable to deflect light from the lens that is incident on the first light deflector towards the first peripheral light detector, and a second light deflector positioned over the relatively large second end portion of the shaped aperture and operable to deflect light from the lens that is incident on the second light deflector towards the second peripheral light detector, wherein each of the first and second light deflectors overlie a portion of the shaped aperture that is larger than the relatively small center portion; and a controller operably connected to receive signals from the center light detector and from the first and second peripheral light detectors.