A method of collecting particles from a gas-particle stream having a first temperature and a plurality of particles, the method comprising: cooling an interior surface of a collection chamber to a second temperature less than the first temperature of the gas-particle stream; flowing the gas-particle stream through the chamber, wherein the gas-particle stream is directed along the cooled interior surface of the collection chamber, and a temperature gradient between the gas-particle stream and the cooled interior surface creates a thermophoretic force; and the thermophoretic force attracting the particles from the gas-particle stream to the interior surface of the collection chamber, wherein the particles are deposited onto the interior surface of the collection chamber.