Hybrid generators and methods of using them
Certain embodiments described herein are directed to generators that can be used to sustain a plasma in a driven mode and in an oscillation mode and optionally in a hybrid mode. In some embodiments, the generator is configured to switch between the two modes during operation. In certain instances, the plasma may be ignited when the generator is in a driven mode and may be used to analyze samples when the generator is in an oscillation mode or driven mode or hybrid mode.
1. A mass spectrometer comprising:
a torch configured to sustain an ionization source;
an induction device comprising an aperture for receiving a portion of the torch and configure to provide radio frequency energy into the received torch portion;
a generator electrically coupled to the induction device and configured to provide power to sustain an inductively coupled plasma in the torch portion received by the induction device, the generator comprising a circuit configured to electrically couple to an induction device and provide power to the induction device in the driven mode to sustain the inductively coupled plasma in the received torch portion in the driven mode and configured to provide power to the induction device in the oscillation mode to sustain the inductively coupled plasma in the received torch portion in the oscillation mode; and
a mass analyzer fluidically coupled to the torch.
2. The mass spectrometer of claim 1 , in which the circuit comprises a signal source configured to electrically couple to the induction device.
3. The mass spectrometer of claim 2 , in which the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source.
4. The mass spectrometer of claim 2 , in which the circuit comprises a feedback device configured to electrically couple to the induction device and be enabled during operation of the induction device in the oscillation mode.
5. The mass spectrometer of claim 4 , in which the circuit is configured to disable the feedback device during operation in the driven mode.
6. The mass spectrometer of claim 4 , in which the circuit is configured to enable the feedback device during operation in the oscillation mode.
7. The mass spectrometer of claim 6 , in which the circuit is configured to disable the signal source during operation in the oscillation mode.
8. The mass spectrometer of claim 1 , in which the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode.
9. The mass spectrometer of claim 1 , in which the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode.
10. The mass spectrometer of claim 1 , in which the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode.
11. The mass spectrometer of claim 1 , in which the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device.
12. The mass spectrometer of claim 11 , further comprising a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device.
13. The mass spectrometer of claim 1 , further comprising a detector electrically coupled to the circuit and configured to determine when the plasma is ignited.
14. The mass spectrometer of claim 13 , in which the circuit is configured to switch from the driven mode to the oscillation mode at any time after a plasma is detected by the detector.
15. The mass spectrometer of claim 14 , further comprising a signal converter between the circuit and the detector.
16. The mass spectrometer of claim 1 , in which the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode.
17. The mass spectrometer of claim 1 , in which the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and comprises at least one additional transistor configured to electrically couple to the induction device in the oscillation mode.
18. The mass spectrometer of claim 17 , in which the circuit is configured to disable the at least one transistor during operation in the oscillation mode.
19. The mass spectrometer of claim 17 , in which the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode.
20. The mass spectrometer of claim 1 , in which the induction device comprises an induction coil or a plate electrode.