Patent ID: 7471394

Claim:
A cytometer for analyzing predetermined characteristics of biological particles within a flow stream, the cytometer comprising: a removable flow cytometry cartridge for receiving a sample fluid including biological particles and for hydrodynamic focusing the biological particles into a single file arrangement through an interrogation channel within the removable cartridge, the removable cartridge having a first sidewall with a first optically transparent window in optical communication with the interrogation channel, and a second sidewall opposite to the first sidewall with a second optically transparent window in optical communication with the interrogation channel; a housing for removably receiving the removable flow cytometry cartridge, the housing including: a light source for providing an input light beam to the interrogation channel through the first optically transparent window of the removable flow cytometry cartridge, the input light beam having a polarization direction; a polarizing beamsplitter for receiving an output light beam from the interrogation channel through the second optically transparent window of the removable flow cytometry cartridge, and for providing a polarized light beam and a depolarized light beam, wherein the polarized light beam and the depolarized light beam form an angle therebetween of less than 90 degrees; and light receiving means for receiving the polarized light beam and the depolarized light beam, and for providing a first output signal that corresponds to the polarized light beam and a second output signal that corresponds to the depolarized light beam.