| abstract |
An apparatus for measuring material outgassed from an object. The apparatus has a chamber containing the object, a condensed material detector (e.g. a quartz microbalance), a heater for heating the object and chamber, and a cooler for cooling the detector. The chamber is sealed from the ambient atmosphere and the detector is located within the chamber. The chamber may contain a vacuum or a gas at ambient atmospheric pressure. Material outgassed from the object is distributed throughout the chamber by vapor transport and is incident upon the detector, where it condenses. Since the detector is the only cooled surface in contact with the vapors, it collects nearly all the outgassed material. This provides high sensitivity to outgassing. The chamber may also include a mechanical stirring device for aiding vapor transport, or may be oriented so that a thermal convection current is established. Preferably, the chamber includes a snout for thermally isolating the detector and chamber so that a steep temperature gradient exists close to the detector surface. Alternatively, the detector has a coating with a high affinity for outgassed materials of interest. The chamber, detector, and object are at nearly the same temperature and the outgassed materials preferentially condense on the detector due to the high affinity of the coating for the outgassed materials. |