Flow cell

A flow cell system comprising

• a mixer having first and second inlets for receiving fluids to be mixed and a common mixed fluids outlet,
• a body defining a chamber having a chamber outlet and a chamber inlet connected to the mixer outlet, the chamber inlet comprising:
• a chamber inlet channel connected to the mixer outlet immediately downstream of the junction;
• and
• a plurality of conduits interconnected by the chamber inlet channel, communicating with the chamber in parallel at respective spaced-apart portions of the chamber and dimensioned such that at the predetermined flow rates, fluid flow is laminar immediately upstream of the chamber;
• means for delivering fluids to the mixer inlets at predetermined flow rates, and
• a window covering at least one side of the chamber through which mixed fluids within the chamber may be observed,
• wherein the mixer inlets and mixed fluids outlet are interconnected at a common junction and are dimensioned such that at the predetermined flow rates fluid flow is turbulent immediately upstream and downstream of the junction.