Callibration of capillaries for density measurement of supercooled water

Density of supercooled water at elevated pressure is interesting because of the strong anomalies which can be explained by existence of a liquid-liquid critical point in the region of supercooled water. In order to provide accurate data for density at these conditions a procedure was developed to calibrate the course of the inner cross section of a capillary along its length. Further, the image analysis for the sub-pixel evaluation of meniscus postion is described.