Patent ID: 7269991

Claim:
An apparatus for providing gases for calibration, comprising: at least one source that generates at least one chosen impurity in a known range of nanograms per minute within given temperature ranges and at a predetermined flow rate; a supply of gas that is at least substantially pure; a supply of purge gas; a main gas conduit; a communication between said at least one impurity source and at least a portion of said main conduit; a housing having an interior, wherein said impurity source and at least a portion of said main conduit is located within the interior of said housing; a means for selectively raising and/or lowering the temperature of the housing interior between about 60° F. and about 130° F., wherein the means for selectively raising and/or lowering the temperature comprises a temperature controller that controls the temperature within said housing and a semi-conductor heating and cooling device; and a valve that connects the supply of pure gas and the supply of purge gas to the main conduit, wherein: said pure gas flows through said main conduit and passes by said communication, the impurity from said source diffuses into said pure gas that flows past said communication thereby producing a calibration gas; and the purge gas and the pure gas are introduced into the main conduit at different times.