Forward scattered light detection system, flow cytometer and method for measuring cell diameter

A flow cytometer comprising:

• a forward scattered light detection system that comprises:
• a laser, configured to emit light rays;
• a light focusing assembly, configured to focus the light rays as a light spot;
• a first lens, configured to convert the light spot to parallel light rays, wherein
• a center of the light spot is located on a main optical axis of the first lens;
• a blocking assembly, configured to transmit a light ray propagating along and near the main optical axis through the blocking assembly and block most of the light rays propagating in directions other than the main optical axis, wherein the blocking assembly comprises a first blocking plate and a second blocking plate arranged on two opposite sides of the first lens;
• and
• a first detector, configured to detect an intensity of the light ray transmitted from the blocking assembly to the first detector;
• and
• a fluidics system between the light focusing assembly and the first lens,
• wherein the main optical axis is perpendicular to and intersected with a flow direction of a cell suspension in the fluidics system,
• wherein the fluidics system comprises:
• a cylindrical steady flow cavity, configured to accommodate a sheath fluid;
• a sample channel, configured to import the cell suspension, wherein the sample channel is in a center of the cylindrical steady flow cavity, a conical confluent cavity, in communication with the cylindrical steady flow cavity and the sample channel;
• and
• a capillary tube, connected to an exit of the conical confluent cavity, wherein an extending direction of the capillary tube perpendicularly intersects the main optical axis of the forward scattered light detection system, and
• wherein the fluidics system is configured to:
• enable the sheath fluid and the cell suspension to simultaneously flow into the conical confluent cavity respectively through the cylindrical steady flow cavity and the sample channel, to make the sheath fluid encircle a cell in the cell suspension after confluence;
• and
• enable the light rays to be scattered by the encircled cell that flows in the capillary tube when the encircled cell flows to a position where the capillary tube intersects the main optical axis of the forward scattered light detection system.