| Abstract: | Apparatus and method for collecting particles of both high and low vapor
pressure target materials entrained in a large volume sample gas stream.
Large volume active cooling provides a cold air supply which is mixed
with the sample gas stream to reduce the vapor pressure of the particles.
In embodiments, a chiller cools air from ambient conditions to
0-15.degree. C. with the volumetric flow rate of the cold air supply
being at least equal to the volumetric flow rate of the sample gas
stream. In further embodiments an adsorption media is heated in at least
two stages, a first of which is below a threshold temperature at which
decomposition products of the high vapor pressure particle are generated. |