Patent ID: 8753891

Claim:
A method comprising: providing a collimated light source operable to generate a collimated light source beam, the collimated light source beam comprising a beam cross-section; providing a body defining a first channel in a first plane, the first channel comprising a wall, a second channel in a second plane orthogonal to said first plane, said second channel communicating with said first channel, said second channel comprising a second channel cross-section, said second channel being oriented to receive the collimated light source beam, and a third channel in a third plane orthogonal to said second plane, said third channel communicating with said second channel; transmitting the collimated light source beam through the second channel, the transmitted collimated light source beam comprising a beam direction, wherein the collimated light source beam is oriented to enter a cross-section of the third channel, then to pass through the first channel, and then to enter a cross-section of the second channel; transmitting a fluid sample through the second channel, the fluid sample comprising a plurality of particles of a same type, the fluid sample comprising a flow direction opposite the beam direction; retaining all of the particles in the plurality of particles axially along the collimated light source beam; and separating all of the particles of the plurality of particles axially along the collimated light source beam; and retaining all of the particles of the plurality of particles against the wall of the first channel in the collimated light source beam.