Abstract: A method for increasing the intensity of the excitation light, and thereby the sensitivity, of flow cytometers. The initial part of the signal produced by each cell as it enters the excitation focus triggers a current pulse to the excitation light source, with a duration approximately similar to the time required for the cell to pass through the focus. This current pulse, which is superimposed on the constant operating current to the light source, causes an increase of the intensity of the excitation light during the period when the cell is passing through the excitation focus and thereby an increase of the sensitivity of the flow cytometer.

Abstract: A system for filtering, purification, and recirculation of the sample carrier water in a flow cytometer. After running through the flow chamber of the flow cytometer, the water, including the sample, is passed through physical and chemical filters to remove cells, cell debris and other particulate matter as well as dyes, before the water is recycled through the instrument as carrying, or sheath fluid for subsequent samples.