Abstract: In a high frequency oscillator system a series oscillator circuit includes a load coil inductively coupled with a plasma generator. A capacitance is in series with the coil between the drain and source terminals of a transistor. A capacitive or inductive feedback responsive to the oscillation is connected to the gate terminal of the transistor. In another embodiment two sections of a series circuit are connected by the load coil, each section including a separate transistor. A first capacitance is connected between the coil and the first transistor drain, and a second capacitance is connected between the coil and the second transistor drain. A first capacitive feedback is connected between the second section and the first transistor gate, and a second capactive feedback is connected between the first section and the second transistor gate.

Abstract: In a mounting apparatus for an induction coupled plasma generator, a housing assembly has a receptacle with a central opening aligned over a housing wall opening, electrical contact rings in the receptacle, and a gas block with a central aperture aligned with the openings. An outer passage in the gas block receives a plasma forming gas and extends to the central aperture. A mounting assembly has a mounting member with an annular contact ring, a second gas block, and a gas tube and a sample tube extending from the second gas block. The second gas block has an inner passage extending into the gas tube. The mounting assembly removably engages to the housing assembly, with the mounting member on the receptacle, the second gas block in the first gas block, and the rings in contact. The tubes extend to a load coil for the plasma, and the passages align to convey the plasma forming gas into the gas tube.

Abstract: A plasma flame apparatus capable of self-extinguishing in the event of an unstable plasma discharge includes an inductively coupled plasma torch for producing a plasma flame which will have an acoustical signal characteristic of an unstable plasma discharge. A power generator is coupled to the plasma torch for powering the plasma. A microphone is receptive of the acoustical signal for effecting a representative electrical signal. A comparator generates a output electrical signal when the representative signal exceeds a selected level. The output signal is coupled to the power generator of the plasma flame such as to shut off the power generator when the representative signal exceeds the selected level.

Abstract: An induction plasma system comprises a torch and an induction coil. A sample substance is injected into the plasma at an axial position that is adjustable while the plasma is being energized. The plasma-forming gas flows through the induction coil prior to passing through the plasma torch. A piezoelectric crystal is used for initiating the plasma. An oscillator network generates radio frequency power at a first frequency, and an output LC network that includes the induction coil is tuned to a second frequency higher than the first frequency. Means for maintaining constant power to the plasma includes an AC circuit for duty cycling AC power input to a DC power supply in response to a feedback signal relative to the rectified voltage. Thus a change in the rectified voltage effects an inverse change in the duty cycling such as to nullify the change in the rectified voltage.

Abstract: An impedance matching network for continuously and automatically maximizing RF power transfer to a plasma emission torch includes a dual phase detector network. Signals from the detector network control, via a control unit, a variable impedance network.