Gas Pycnometers

Gas pycnometers measure the true density of solid materials using an inert gas, which will typically be helium or nitrogen. A sample is placed in a sealed sample chamber within the pycnometer, which is then pressurized to a target pressure and later recorded. The opening of an expansion valve between the sample chamber and reference chamber allows gas to expand to the reference chamber, creating a pressure drop ratio. This pressure drop ratio determines the density of a given sample by comparing the readings to a previously measured volume of a standard that has been recorded through the same process.