Patent Grant
9420679
This application is related to generators and methods of using them. More particularly, certain embodiments described herein are directed to a generator that is operative in a driven mode and in an oscillation mode (and optionally in a hybrid mode) to sustain a plasma or other atomization/ionization device.
Generators are commonly used to sustain a plasma within a torch body. A plasma includes charged particles. Plasmas have many uses including atomizing and/or ionizing chemical species.
Certain aspects, attributes and features are directed to hybrid generators that may be operated in a driven mode, an oscillation mode or a hybrid mode where both the driven and oscillation modes are active for at least some period. The generator may be used to power many different types of devices including, but not limited to, induction devices.
In a first aspect, a generator configured to provide power to sustain an inductively coupled plasma in a torch body in a driven mode and in an oscillation mode, 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 torch body 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 torch body in the oscillation mode, and a processor electrically coupled to the circuit and configured to switch operation of the circuit between the driven mode and the oscillation mode is provided.
In certain configurations, the circuit comprises a signal source configured to electrically couple to the induction device. In other configurations, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In some embodiments, 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. In other embodiments, the processor is configured to disable the feedback device during operation in the driven mode. In some instances, the processor is configured to enable the feedback device during operation in the oscillation mode. In certain examples, the processor is configured to disable the signal source during operation in the oscillation mode. In some embodiments, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In other instances, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In some embodiments, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In other embodiments, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In some instances, the generator comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In other embodiments, the generator comprises a detector electrically coupled to the processor and configured to determine when the plasma is ignited. In some embodiments, the processor is configured to switch from the driven mode to the oscillation mode at any time after a plasma is detected by the detector. In some embodiments, the generator comprises a signal converter between the processor and the detector. In certain instances, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In some embodiments, 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. In other embodiments, the processor is configured to disable the at least one transistor during operation in the oscillation mode. In some instances, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In other instances, the circuit is configured to electrically couple to an induction device that comprises an induction coil or a plate electrode.
In another aspect, a generator configured to provide power to sustain an inductively coupled plasma in a torch body in a driven mode and in an oscillation mode, 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 torch body 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 torch body in the oscillation mode is described.
In certain examples, the circuit comprises a signal source configured to electrically couple to the induction device. In other examples, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In some embodiments, 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. In some configurations, the circuit is configured to disable the feedback device during operation in the driven mode. In other embodiments, the circuit is configured to enable the feedback device during operation in the oscillation mode. In some examples, the circuit is configured to disable the signal source during operation in the oscillation mode. In certain instances, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In some embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In other embodiments, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In certain examples, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In some embodiments, the generator comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In other embodiments, the generator comprises a detector electrically coupled to the circuit and configured to determine when the plasma is ignited. In certain configurations, 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. In some configurations, the generator comprises a signal converter between the circuit and the detector. In certain embodiments, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In some examples, 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. In other examples, the circuit is configured to disable the at least one transistor during operation in the oscillation mode. In certain embodiments, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In some embodiments, the circuit is configured to electrically couple to an induction device comprising an induction coil or a plate electrode.
In an additional aspect, a generator configured to power an induction device, the generator comprising a circuit configured to provide power to the induction device in a driven mode in a first state of the circuit and to provide power to the induction device in an oscillation mode in a second state of the circuit is described.
In certain embodiments, the generator is configured to operate in the driven mode during ignition of an inductively coupled plasma. In some embodiments, the generator is configured to switch from the first state to the second state after ignition of the inductively coupled plasma. In certain examples, the circuit comprises a signal source configured to provide a selected frequency to the induction device that maximizes the induction device voltage and/or power. In some examples, the signal source is disabled in the second state of the circuit. In certain configurations, the circuit comprises a sensor configured to determine when an inductively coupled plasma has been ignited. In other configurations, the generator switches from the first state to the second state after the sensor detects the plasma has been ignited. In some embodiments, the circuit comprises feedback means configured to be disabled in the first state and enabled during the second state. In certain embodiments, the feedback means comprises at least one feedback device electrically coupled to the induction device. In other examples, the circuit comprises a signal source electrically coupled to the induction device through drive amplifiers configured to provide power to the induction device in the driven modem, the circuit further comprising a feedback device electrically coupled to the induction device and configured to be enabled during the oscillation mode, and a switch electrically coupled to the circuit and the feedback device and configured to switch operation of the generator from the driven mode to the oscillation mode. In some examples, the feedback circuit is configured to provide impedance matching within about three RF cycles. In certain embodiments, the generator comprises at least one transistor configured to be enabled in the driven mode and be disabled in the oscillation mode. In some examples, the generator comprises at least one transistor configured to be disabled in the driven mode and be enabled in the oscillation mode. In certain examples, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In some configurations, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In other configurations, the generator comprises a detector configured to electrically couple to the induction device. In some configurations, the circuit is configured to switch from the driven mode to the circuit mode when plasma ignition is detected by the detector. In other configurations, the generator comprises a signal converter electrically coupled to the detector. In some embodiments, each of the transistors is enabled in a hybrid mode. In other embodiments, the circuit is configured to electrically couple to an induction device comprising an induction coil or a plate electrode.
In another aspect, a system comprising an induction device, and a generator electrically coupled to the induction device and configured to provide power to sustain an inductively coupled plasma in a 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 torch body 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 torch body in the oscillation mode, and a processor electrically coupled to the circuit and configured to switch operation of the circuit between the driven mode and the oscillation mode is disclosed.
In certain configurations, the circuit comprises a signal source configured to electrically couple to the induction device. In other configurations, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In some embodiments, 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. In further embodiments, the processor is configured to disable the feedback device during operation in the driven mode. In some instances, the processor is configured to enable the feedback device during operation in the oscillation mode. In certain embodiments, the processor is configured to disable the signal source during operation in the oscillation mode. In some examples, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In other examples, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In further examples, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In additional examples, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In some embodiments, the system comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In certain embodiments, the system comprises a detector electrically coupled to the processor and configured to determine when the plasma is ignited. In other embodiments, the processor is configured to switch from the driven mode to the oscillation mode at any time after a plasma is detected by the detector. In some configurations, the system comprises a signal converter between the processor and the detector. In other configurations, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In certain configurations, 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. In some embodiments, the processor is configured to disable the at least one transistor during operation in the oscillation mode. In other embodiments, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In other embodiments, the induction device comprises an induction coil or a plate electrode.
In an additional aspect, a system comprising an induction device, and a generator electrically coupled to the induction device and configured to provide power to the induction device to sustain an inductively coupled plasma in a 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 torch body 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 torch body in the oscillation mode is provided.
In certain configurations, the circuit comprises a signal source configured to electrically couple to the induction device. In other configurations, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In additional configurations, 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. In some embodiments, the circuit is configured to disable the feedback device during operation in the driven mode. In other embodiments, the circuit is configured to enable the feedback device during operation in the oscillation mode. In further embodiments, the circuit is configured to disable the signal source during operation in the oscillation mode. In certain examples, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In further embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In other embodiments, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In additional embodiments, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In other instances, the system comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In some instances, the system comprises a detector electrically coupled to the circuit and configured to determine when the plasma is ignited. In certain examples, 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. In other examples, the system comprises a signal converter between the circuit and the detector. In some examples, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In certain configurations, 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. In other configurations, the circuit is configured to disable the at least one transistor during operation in the oscillation mode. In some embodiments, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In other instances, the induction device comprises an induction coil or a plate electrode.
In another aspect, a system comprising an induction device, and a generator electrically coupled to the induction device and comprising a circuit configured to provide power to the induction device in a driven mode in a first state of the circuit and to provide power to the induction device in an oscillation mode in a second state of the circuit is described.
In certain instances, the generator is configured to operate in the driven mode during ignition of an inductively coupled plasma. In other embodiments, the generator is configured to switch from the first state to the second state after ignition of the inductively coupled plasma. In some examples, the circuit comprises a signal source configured to provide a selected frequency to the induction device that maximizes the induction device voltage and/or power. In certain embodiments, the signal source is disabled in the second state of the circuit. In some examples, the circuit comprises a sensor configured to determine when an inductively coupled plasma has been ignited. In other examples, the generator is configured to switch from the first state to the second state after the sensor detects the plasma has been ignited. In certain configurations, the circuit comprises feedback means configured to be disabled in the first state and enabled during the second state. In other configurations, the feedback means comprises at least one feedback device electrically coupled to the induction device. In some embodiments, the circuit comprises a signal source electrically coupled to the induction device through drive amplifiers configured to provide power to the induction device in the driven modem, the circuit further comprising a feedback device electrically coupled to the induction device and configured to be enabled during the oscillation mode, and a switch electrically coupled to the circuit and the feedback device and configured to switch operation of the generator from the driven mode to the oscillation mode. In some instances, the feedback circuit is configured to provide impedance matching within about three RF cycles. In other instances, the generator comprises at least one transistor configured to be enabled in the driven mode and be disabled in the oscillation mode. In some embodiments, the generator comprises at least one transistor configured to be disabled in the driven mode and be enabled in the oscillation mode. In other embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In some examples, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In other examples, the system comprises a detector configured to electrically couple to the induction device. In some examples, the circuit is configured to switch from the driven mode to the circuit mode when plasma ignition is detected by the detector. In other embodiments, the system comprises a signal converter electrically coupled to the detector. In some examples, each of the transistors is enabled in a hybrid mode. In other examples, the circuit is configured to electrically couple to an induction device comprising an induction coil or a plate electrode.
In an additional aspect, 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 processor electrically coupled to the circuit and configured to switch operation of the circuit between the driven mode and the oscillation mode, and a mass analyzer fluidically coupled to the torch is provided.
In certain examples, the circuit comprises a signal source configured to electrically couple to the induction device. In other examples, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In some embodiments, 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. In other embodiments, the processor is configured to disable the feedback device during operation in the driven mode. In some examples, the processor is configured to enable the feedback device during operation in the oscillation mode. In certain configurations, the processor is configured to disable the signal source during operation in the oscillation mode. In other configurations, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In some embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In certain examples, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In some embodiments, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In certain embodiments, the mass spectrometer comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In some instances, the mass spectrometer comprises a detector electrically coupled to the processor and configured to determine when the plasma is ignited. In other instances, the processor is configured to switch from the driven mode to the oscillation mode at any time after a plasma is detected by the detector. In some embodiments, the mass spectrometer comprises a signal converter between the processor and the detector. In other instances, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In certain configurations, 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. In some embodiments, the processor is configured to disable the at least one transistor during operation in the oscillation mode. In other embodiments, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In certain examples, the induction device comprises an induction coil or a plate electrode.
In another aspect, 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 is disclosed.
In certain configurations, the circuit comprises a signal source configured to electrically couple to the induction device. In some configurations, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In other configurations, 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. In certain examples, the circuit is configured to disable the feedback device during operation in the driven mode. In some embodiments, the circuit is configured to enable the feedback device during operation in the oscillation mode. In certain examples, the circuit is configured to disable the signal source during operation in the oscillation mode. In some examples, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In certain instances, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In other instances, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In some embodiments, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In certain embodiments, the mass spectrometer comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In certain instances, the mass spectrometer comprises a detector electrically coupled to the circuit and configured to determine when the plasma is ignited. In other instances, 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. In some examples, the mass spectrometer comprises a signal converter between the circuit and the detector. In certain configurations, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In some configurations, 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. In other configurations, the circuit is configured to disable the at least one transistor during operation in the oscillation mode. In certain embodiments, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In other examples, the induction device comprises an induction coil or a plate electrode.
In an additional aspect, 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 torch, a generator electrically coupled to the induction device and comprising a circuit configured to provide power to the induction device in a driven mode in a first state of the circuit and to provide power to the induction device in an oscillation mode in a second state of the circuit, and a mass analyzer fluidically coupled to the torch is described.
In certain instances, the generator is configured to operate in the driven mode during ignition of an inductively coupled plasma. In some embodiments, the generator is configured to switch from the first state to the second state after ignition of the inductively coupled plasma. In other embodiments, the circuit comprises a signal source configured to provide a selected frequency to the induction device that maximizes the induction device voltage and/or power. In some configurations, the signal source is disabled in the second state of the circuit. In other embodiments, the circuit comprises a sensor configured to determine when an inductively coupled plasma has been ignited. In certain embodiments, the generator is configured to switch from the first state to the second state after the sensor detects the plasma has been ignited. In certain examples, the circuit comprises feedback means configured to be disabled in the first state and enabled during the second state. In some examples, the feedback means comprises at least one feedback device electrically coupled to the induction device. In other instances, the circuit comprises a signal source electrically coupled to the induction device through drive amplifiers configured to provide power to the induction device in the driven modem, the circuit further comprising a feedback device electrically coupled to the induction device and configured to be enabled during the oscillation mode, and a switch electrically coupled to the circuit and the feedback device and configured to switch operation of the generator from the driven mode to the oscillation mode. In some embodiments, the feedback circuit is configured to provide impedance matching within about three RF cycles. In other embodiments, the generator comprises at least one transistor configured to be enabled in the driven mode and be disabled in the oscillation mode. In some examples, the generator comprises at least one transistor configured to be disabled in the driven mode and be enabled in the oscillation mode. In certain configurations, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In other configurations, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In additional configurations, the mass spectrometer comprises a detector configured to electrically couple to the induction device. In some instances, the circuit is configured to switch from the driven mode to the circuit mode when plasma ignition is detected by the detector. In other instances, the mass spectrometer comprises a signal converter electrically coupled to the detector. In certain instances, each of the transistors is enabled in a hybrid mode. In other instances, the induction device comprises an induction coil or a plate electrode.
In another aspect, a system for detecting optical emission, the system 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 torch, 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 processor electrically coupled to the circuit and configured to switch operation of the circuit between the driven mode and the oscillation mode, and an optical detector configured to detect optical emissions in the torch is described.
In some embodiments, the circuit comprises a signal source configured to electrically couple to the induction device. In certain embodiments, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In other embodiments, 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. In further instances, the processor is configured to disable the feedback device during operation in the driven mode. In other instances, the processor is configured to enable the feedback device during operation in the oscillation mode. In certain instances, the processor is configured to disable the signal source during operation in the oscillation mode. In some embodiments, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In certain embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In other embodiments, circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In certain configurations, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In some configurations, the system comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In certain configurations, the system comprises a detector electrically coupled to the processor and configured to determine when the plasma is ignited. In some configurations, the processor is configured to switch from the driven mode to the oscillation mode at any time after a plasma is detected by the detector. In some instances, the system comprises a signal converter between the processor and the detector. In other instances, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In some embodiments, 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. In certain embodiments, the processor is configured to disable the at least one transistor during operation in the oscillation mode. In some instances, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In other instances, the induction device comprises an induction coil or a plate electrode.
In an additional aspect, a system for detecting optical emission, the system 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 torch, a generator electrically coupled to the induction device and configured to provide power to the induction device 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 an optical detector configured to detect optical emissions in the torch is provided.
In certain examples, the circuit comprises a signal source configured to electrically couple to the induction device. In other examples, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In some embodiments, 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. In some instances, the circuit is configured to disable the feedback device during operation in the driven mode. In further instances, the circuit is configured to enable the feedback device during operation in the oscillation mode. In some configurations, the circuit is configured to disable the signal source during operation in the oscillation mode. In other configurations, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In certain examples, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In some embodiments, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In certain embodiments, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In other embodiments, the system comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In some instances, the system comprises a detector electrically coupled to the circuit and configured to determine when the plasma is ignited. In other instances, 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. In some embodiments, the system comprises a signal converter between the circuit and the detector. In other instances, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In some embodiments, 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. In certain instances, the circuit is configured to disable the at least one transistor during operation in the oscillation mode. In other instances, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In some embodiments, the induction device comprises an induction coil or a plate electrode.
In other aspects, a system for detecting optical emission, the system comprising a torch configured to sustain an ionization source, an induction device comprising an aperture for receiving a portion of the torch and configured to provide radio frequency energy into the torch, a generator electrically coupled to the induction device and comprising a circuit configured to provide power to the induction device in a driven mode in a first state of the circuit and to provide power to the induction device in an oscillation mode in a second state of the circuit, and an optical detector configured to detect optical emissions in the torch is described.
In some embodiments, the generator is configured to operate in the driven mode during ignition of an inductively coupled plasma. In certain embodiments, the generator is configured to switch from the first state to the second state after ignition of the inductively coupled plasma. In other embodiments, the circuit comprises a signal source configured to provide a selected frequency to the induction device that maximizes the induction device voltage and/or power. In further embodiments, the signal source is disabled in the second state of the circuit. In some examples, the circuit comprises a sensor configured to determine when an inductively coupled plasma has been ignited. In additional examples, the generator switches from the first state to the second state after the sensor detects the plasma has been ignited. In some examples, the circuit comprises feedback means configured to be disabled in the first state and enabled during the second state. In certain embodiments, the feedback means comprises at least one feedback device electrically coupled to the induction device. In certain instances, the circuit comprises a signal source electrically coupled to the induction device through drive amplifiers configured to provide power to the induction device in the driven modem, the circuit further comprising a feedback device electrically coupled to the induction device and configured to be enabled during the oscillation mode, and a switch electrically coupled to the circuit and the feedback device and configured to switch operation of the generator from the driven mode to the oscillation mode. In some examples, the feedback circuit is configured to provide impedance matching within about three RF cycles. In certain configurations, the generator comprises at least one transistor configured to be enabled in the driven mode and be disabled in the oscillation mode. In some embodiments, the generator comprises at least one transistor configured to be disabled in the driven mode and be enabled in the oscillation mode. In other embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In certain examples, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In further examples, the system comprises a detector configured to electrically couple to the induction device. In some examples, the circuit is configured to switch from the driven mode to the circuit mode when plasma ignition is detected by the detector. In other examples, the system comprises a signal converter electrically coupled to the detector. In other configurations, each of the transistors is enabled in a hybrid mode. In additional configurations, the induction device comprises an induction coil or a plate electrode.
In additional aspects, a system for detecting atomic absorption emission, the system comprising a torch configured to sustain an ionization source, an induction device comprising an aperture for receiving a portion of the torch and configured to provide radio frequency energy into the torch, a generator electrically coupled to the induction device and configured to provide power to the induction device 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 processor electrically coupled to the circuit and configured to switch operation of the circuit between the driven mode and the oscillation mode, a light source configured to provide light to the torch, and an optical detector configured to measure the amount of provided light transmitted through the torch is disclosed.
In some embodiments, the circuit comprises a signal source configured to electrically couple to the induction device. In other embodiments, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In further embodiments, 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. In additional embodiments, the processor is configured to disable the feedback device during operation in the driven mode. In some instances, the processor is configured to enable the feedback device during operation in the oscillation mode. In certain examples, the processor is configured to disable the signal source during operation in the oscillation mode. In some embodiments, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In further instances, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In other embodiments, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In additional instances, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In some examples, the system comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In further examples, the system comprises a detector electrically coupled to the processor and configured to determine when the plasma is ignited. In other embodiments, the processor is configured to switch from the driven mode to the oscillation mode at any time after a plasma is detected by the detector. In other examples, the system comprises a signal converter between the processor and the detector. In certain embodiments, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In other examples, 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. In certain configurations, the processor is configured to disable the at least one transistor during operation in the oscillation mode. In additional configurations, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In other configurations, the induction device comprises an induction coil or a plate electrode.
In another aspect, a system for detecting atomic absorption emission, the system comprising a torch configured to sustain an ionization source, an induction device comprising an aperture for receiving a portion of the torch and configured to provide radio frequency energy into the torch, a generator electrically coupled to the induction device and comprising a circuit configured to electrically couple to the 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, a light source configured to provide light to the torch, and an optical detector configured to measure the amount of provided light transmitted through the torch is provided.
In certain embodiments, the circuit comprises a signal source configured to electrically couple to the induction device. In other embodiments, the signal source comprises at least one of a RF frequency synthesizer, a voltage controlled oscillator, and a switchable RF signal source. In some instances, 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. In certain examples, the circuit is configured to disable the feedback device during operation in the driven mode. In some embodiments, the circuit is configured to enable the feedback device during operation in the oscillation mode. In certain instances, the circuit is configured to disable the signal source during operation in the oscillation mode. In other instances, the circuit is configured to provide impedance matching within about three RF cycles when operated in the oscillation mode. In some embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In certain examples, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In some embodiments, the circuit comprises a driving circuit electrically coupled to the induction device and an oscillating circuit electrically coupled to the induction device. In certain configurations, the system comprises a filter electrically coupled to the oscillating circuit and present between feedback devices of the oscillating circuit and the induction device. In some configurations, the system comprises a detector electrically coupled to the circuit and configured to determine when the plasma is ignited. In other configurations, 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. In some embodiments, the system comprises a signal converter between the circuit and the detector. In other embodiments, the circuit comprises at least one transistor configured to electrically couple to the induction device in the driven mode and in the oscillation mode. In additional instances, 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. In other embodiments, the circuit is configured to disable the at least one transistor during operation in the oscillation mode. In some instances, the at least one transistor and the at least one additional transistor are both enabled in a hybrid mode. In some examples, the induction device comprises an induction coil or a plate electrode.
In an additional aspect, a system for detecting atomic absorption emission, the system 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 torch, a generator electrically coupled to the induction device and comprising a circuit configured to provide power to the induction device in a driven mode in a first state of the circuit and to provide power to the induction device in an oscillation mode in a second state of the circuit, a light source configured to provide light to the torch, and an optical detector configured to measure the amount of provided light transmitted through the torch is described.
In certain configurations, the generator is configured to operate in the driven mode during ignition of an inductively coupled plasma. In other configurations, the generator is configured to switch from the first state to the second state after ignition of the inductively coupled plasma. In some embodiments, the circuit comprises a signal source configured to provide a selected frequency to the induction device that maximizes the induction device voltage and/or power. In certain examples, the signal source is disabled in the second state of the circuit. In additional examples, the circuit comprises a sensor configured to determine when an inductively coupled plasma has been ignited. In some examples, the generator switches from the first state to the second state after the sensor detects the plasma has been ignited. In other embodiments, the circuit comprises feedback means configured to be disabled in the first state and enabled during the second state. In further examples, the feedback means comprises at least one feedback device electrically coupled to the induction device. In certain embodiments, the circuit comprises a signal source electrically coupled to the induction device through drive amplifiers configured to provide power to the induction device in the driven modem, the circuit further comprising a feedback device electrically coupled to the induction device and configured to be enabled during the oscillation mode, and a switch electrically coupled to the circuit and the feedback device and configured to switch operation of the generator from the driven mode to the oscillation mode. In some examples, the feedback circuit is configured to provide impedance matching within about three RF cycles. In certain embodiments, the generator comprises at least one transistor configured to be enabled in the driven mode and be disabled in the oscillation mode. In some examples, the generator comprises at least one transistor configured to be disabled in the driven mode and be enabled in the oscillation mode. In other embodiments, the circuit is configured to provide a substantially constant frequency and amplitude to the induction device during operation in the driven mode. In certain examples, the circuit is configured to provide a variable frequency and amplitude during operation in the oscillation mode. In further examples, the system comprises a detector configured to electrically couple to the induction device. In some embodiments, the circuit is configured to switch from the driven mode to the circuit mode when plasma ignition is detected by the detector. In other embodiments, the system comprises a signal converter electrically coupled to the detector. In other embodiments, each of the transistors is enabled in a hybrid mode. In some instances, the induction device comprises an induction coil or a plate electrode.
In another aspect, a chemical reactor comprising a reaction chamber, an induction device comprising an aperture configured to receive some portion of the reaction chamber, and any generator described herein electrically coupled to the induction device and configured to provide power into the received portion of the reaction chamber using the induction device is provided.
In other aspects, a material deposition device comprising an atomization chamber, an induction device comprising an aperture configured to receive some portion of the atomization chamber, any generator described herein electrically coupled to the induction device and configured to provide power into the received portion of the atomization chamber using the induction device, and a nozzle fluidically coupled to the atomization chamber and configured to receive atomized species from the chamber and provide the received, atomized species towards a substrate is disclosed.
In an additional aspect, a system comprising a torch, a first induction device comprising an aperture configured to receive a portion of the torch, a second induction device comprising an aperture configured to receive a second portion of the torch, a first generator electrically coupled to the first induction device and a second generator electrically coupled to the second induction device, in which at least one of the first generator and the second generator is any one of the generators described herein is provided.
In another aspect, a method of igniting and sustaining a plasma with a single generator, the method comprising igniting a plasma in a torch body by providing power to an induction device from the generator in a driven mode, and switching the generator from the driven mode to an oscillation mode any time after the plasma is ignited is described.
In an additional aspect, a method of igniting and sustaining a plasma with a single generator, the method comprising igniting a plasma in a torch body by providing power to an induction device from a generator configured to provide power to the induction device in a driven mode and in an oscillation mode, and sustaining the plasma using the driven mode of the generator is described.
In another aspect, a method of igniting and sustaining a plasma with a single generator, the method comprising igniting a plasma in a torch body by providing power to an induction device from a generator configured to provide power to the induction device in a driven mode and in an oscillation mode, and sustaining the plasma using the oscillation mode of the generator. In some instances, the plasma is ignited by providing power from the generator in the oscillation mode. In other instances, the method comprises switching the generator to the driven mode after the plasma is sustained for some period using the oscillation mode.
In an additional aspect, a method of measuring the quality of an inductively coupled plasma system sustained using an induction device, the method comprising providing a control signal to the induction device from a generator electrically coupled to the induction device, the generator configured to provide power to the induction device in a driven mode and an oscillation mode, in which the control signal is provided when the generator is operated in the driven mode, and monitoring system response to the control signal to assess the condition of the inductively coupled plasma system is described.
In other aspects, a generator circuit as shown in
In an additional aspect, an oscillator circuit as shown in the generator circuit of
In another aspect, a method of sustaining an inductively coupled plasma, the method comprising providing power to a torch in an oscillation mode using a generator circuit as shown in
In other aspects, a method of sustaining an inductively coupled plasma, the method comprising providing power to a torch in a driven mode using a generator circuit as shown in
In additional aspects, a method of sustaining an inductively coupled plasma, the method comprising providing power to a torch in a hybrid mode using a generator circuit as shown in
In other aspects, a method of sustaining an inductively coupled plasma, the method comprising providing power to a torch in an oscillation mode using a generator circuit as shown in any
In additional aspects, a method of sustaining an inductively coupled plasma, the method comprising providing power to a torch in a driven mode using a generator circuit as shown in
In other aspects, a method of sustaining an inductively coupled plasma, the method comprising providing power to a torch in a hybrid mode using a generator circuit as shown in
Additional features, aspects, examples, configurations and embodiments are described in more detail below.
Certain embodiments of the devices and systems are described with reference to the accompanying figures in which:
It will be recognized by the person of ordinary skill in the art, given the benefit of this disclosure, that certain dimensions or features of the components of the systems may have been enlarged, distorted or shown in an otherwise unconventional or non-proportional manner to provide a more user friendly version of the figures. In addition, the exact length, width, geometry, aperture size, etc. of the torch body, the plasmas generated and other components herein may vary.
Certain embodiments are described below with reference to singular and plural terms in order to provide a user friendly description of the technology disclosed herein. These terms are used for convenience purposes only and are not intended to limit the devices, methods and systems described herein. Certain examples are described herein with reference to the terms driven mode and oscillation mode. While the exact parameters used in the driven mode and in the oscillation mode may vary, the RF generator frequency for plasma generation is usually from 10 MHz to 90 MHz, more particularly between 20 MHz and 50 MHz, for example about 40 MHz. The RF generator output power is typically about 500 Watts to 50 kW. As described in more detail herein, in the driven mode of operation, the feedback loop can be disabled and the voltage can be selected to provide a desired power to the induction device. In the oscillation mode, the feedback loop can be enabled to permit rapid changing of the impedance. If desired, the generator can operate entirely in the driven mode, which can achieve a higher sensitivity for mass spectrometry in certain applications, compared to the oscillation mode. In some embodiments, the driven+oscillator hybrid generator may be part of ICP-OES or ICP-MS or other similar instruments as described herein. In certain embodiments, generator operation can be controlled with a processor or master controller in or electrically coupled to the generator to control the generator, e.g., to enable or terminate the plasma generation. While two modes are possible with the generators described herein, if desired, the generator can be operated in only a single mode, e.g., in only the drive mode or in only the oscillation mode.
Certain embodiments are also described below that use a generator to generate and/or sustain an inductively coupled plasma. If desired, however, the same generator can be used to generate and/or sustain a capacitively coupled plasma, a flame or other atomization/ionization devices that can be used, for example, to atomize and/or ionize chemical species. Certain configurations are provided below using inductively coupled plasmas to illustrate various aspects and attributes of the technology described herein.
In certain examples, the generators described herein can be used to sustain a high-energy plasma to atomize and/or ionize samples for chemical analysis, to provide ions for deposition or other uses. To ignite and sustain the plasma, RF power, typically in the range of 0.5 kW to 100 kW, from a RF generator (RFG) is inductively coupled to the plasma by a load coil, plate electrode or other suitable induction devices. The plasma exhibits different RF impedance during the ignition phase and when the plasma is subject to different chemical samples. To facilitate optimal power transfer, the RF generator can be configured to adapt the impedance matching to the varying plasma impedance.
In certain embodiments, existing RF generators are configured to operate using only one of the two methods: the oscillator method (or mode) or the driven method (or mode). Each of these methods has advantages and weaknesses. In the oscillation method, the RF generator is a power oscillator circuit. The oscillation frequency is determined by the oscillator's resonant circuit. In many instances, the plasma impedance and the induction device are part of the resonator and feedback path, so that the oscillating frequency can be rapidly changed to adapt to the varying plasma impedance. This attribute facilitates the analysis of different unknown samples at a high throughput rate. When the oscillation method is implemented during plasma ignition, the RF impedance of the induction device can change substantially and abruptly from no plasma to successful plasma generation. Prior to ignition, the induction device behaves like an inductor such that all the RF power provided to the inductor is substantially reactive power (i.e., no real power). After successful plasma ignition, the inductive device inductively couples real power to the plasma. The feedback signals of the oscillator, which are derived from the induction device, to drive the power transistors change abruptly as well. As a result, during plasma ignition the feedback signals are poorly controlled, and there is a substantial risk in damaging the power electronics when the oscillation method is implemented for plasma ignition. The breakdown of silicon power transistors, which are most commonly used for RF power generation at the aforementioned frequency range, is about −6V to +12V at the gate (input), and about +150V for drain breakdown. Older but slower silicon transistors may have gate breakdown limits from −40V to +40V. Damage prevention of the electronics is particularly desirable because advancements in semiconductor technologies is often achieved by device scaling (e.g., to a smaller gate length), such that the transistor speed (e.g., unity gain frequency Ft, or the maximum oscillation frequency Fmax) is increased at the expense of a lower device breakdown voltage limit. The increase in the transistor speed facilitates the design of a high efficiency power amplifier (e.g., class C, class D, class E, class F, etc.), because the available power gain at the higher harmonics above the fundamental frequency can used to optimize the signal waveform and current conduction angle. Implementation of these high speed, lower breakdown devices can be weighed against the not well controlled feedback signal during ignition. A rapid increase in the feedback signal amplitude can rapidly reinforce an uncontrolled positive feedback loop such that the transistors of the generator are destroyed. The excessive signals can be difficult to suppress or control because of the high frequency, high power and the inherent instability in an oscillator for plasma ignition. If the feedback signal is suppressed too much to safeguard the transistor, the plasma may fail to ignite. Furthermore, the oscillator design can manifest higher RF spurious signals and higher phase noise. Such imperfections may compromise the equipment sensitivity. To overcome these issues, a generator configured to implement only the oscillation method would typically include higher breakdown transistors that are more expensive and/or lower speed and efficiency to avoid potential damage to the circuitry components.
Generators configured to implement only the driven method (or mode) typically utilize a stable RF source which operates at a controlled frequency and amplitude, e.g., a frequency that is adjustable or fixed (but can vary) and is predetermined or preselected. Typical examples of signal sources are small signal, e.g., less than 10 Watt, RF synthesizers or voltage-controlled oscillators (VCO) comprising high-quality crystal, RLC or RC resonators. A RF power amplifier magnifies the small controlled RF signal to a high power level for plasma generation. The driven method is advantageous for plasma ignition because the controlled frequency and signal amplitude can be selected to avoid transistor breakdown. In addition, in many instances, the driven method can produce a spectrally purer RF signal, e.g., a signal spectrum with a strong signal tone at the intended signal frequency and less RF spurious signals. In some configurations, it is easier to use a driven mode RF generator to achieve higher sensitivity for mass spectrometry, compared to an oscillation mode RF generator. However, impedance matching in generators configured to implement the driven method is often much slower than those implementing the oscillation method. A driven RF generator adjusts the controlled frequency (or phase) and/or the amplitude by monitoring the RF impedance change, so that a feedback (or error) signal can be generated to adjust the frequency or phase of the RF source, typically by means of a phase-locked loop (PLL). In the oscillator method, the change is often within a couple of RF cycles, whereas the change in the driven method is at a rate of tens to thousands of RF cycles or at least 10-1000× slower than the oscillation method. As a result, it is more difficult to design a driven RF generator for high throughput mass spectrometry analysis. RF power amplifiers used in the driven method are often designed to drive standard 50 Ohm or 75 Ohm loads. Additional impedance matching between a 50 Ohm (or 75 Ohm) load to the transistors further complicates the design, increases components and footprint area, and can cause unwanted power loss.
In certain configurations of the generators described herein, the generators may include suitable components to permit operation in the driven mode and in the oscillation mode. The generator may switch (if desired) between the two modes during different periods of operation of the plasma to provide optimum power to the plasma at different periods. For example, during ignition of the plasma, the generator may be operated in the driven mode to provide better control of the frequency and signal amplitude to avoid transistor breakdown. After ignition of the plasma, the generator can remain in the driven mode, if desired, or may be switched to the oscillation mode to permit more rapid impedance matching with changes in the plasma that may occur during introduction of samples. The ability to implement both the driven mode and the oscillation mode using a single generator permits the use of lower breakdown transistors that are more inexpensive and/or provide higher speeds and efficiency. While various embodiments are described herein as using the hybrid generator in the driven mode to ignite the plasma, if desired, the generator may be operated in the oscillation mode during plasma ignition and/or after plasma ignition.
In certain examples, the generators described herein may include suitable components and circuitry to permit operation in both the driven mode and the oscillation mode and to permit rapid switching between the two modes. For example, the generator may comprise power transistors, driver amplifiers, various switches, e.g., an RF switch, and an impedance matching network. Feedback signals derived from the induction device outputs can be used to drive the power transistors by a switch (or a variable-gain circuit). The feedback signals can be enabled, disabled or adjusted in amplitude by the switch, typically implemented with an adjustable gain circuit element (e.g., single-stage transistor, multi-stage amplifier, variable gain amplitude, variable digital or analog attenuator, variable capacitor or other adjustable coupling devices, etc.). The saturated output power of the switch or “switching” circuit can be selected to limit or control the physical power of the feedback signal. For example, if a single-stage transistor is used as a switch, the power supply, e.g., a VDD power supply, can be reduced such that the saturated (maximum) output power of the switch is always lower than the maximum input power allowed by the power transistors. In this configuration, the transistors are protected in the oscillation mode of operation. In addition, a RF driver amplifier can be used to amplify the RF source to drive the power transistors. When these components are implemented together, the RF generator can be operated in the driven mode, an oscillation mode and an injection-locked mode, which is a hybrid mode with characteristics of both the driven mode and the oscillation mode and is present during the transition from the driven mode to the oscillation mode or vice versa. In certain embodiments when the driven mode is implemented, the feedback signals are disabled by the switches and the RF driver amplifier is enabled. To switch from the driven mode to the oscillation mode, the feedback signal switches are enabled and the RF driver amplifier is disabled. The RF generator can also be in the injection-locked mode, for example, when both the feedback signals and the RF driver amplifiers are enabled. In this case, the RF generator is running in the oscillation mode, but its operating frequency is locked to the RF source frequency of the driven mode. The ability to switch between the various modes using a single generator provides desirable attributes including, but not limited to, minimizing transistor breakdown in the driven mode during ignition, being able to rapidly change the impedance in the oscillation mode during sample introduction and/or analysis, and the ability to use cheaper and faster transistors while reducing the likelihood of transistor failure. If desired, the generator may be rapidly switched between the driven mode and the oscillation mode and back to the driven mode to sustain a plasma using an almost continuous injection-locked mode.
In certain examples and referring to
In certain embodiments and referring to
In certain examples, once the plasma is ignited and stabilizes, it may be desirable to switch to the oscillation mode by enabling the oscillating circuit and disabling the driving circuit. As noted herein, the oscillation mode provides feedback which can be used to rapidly adjust the impedance of the circuit to provide impedance matching and a more stable plasma in the torch. A schematic of certain active components of a circuit suitable for implementing the oscillation mode is shown in
In certain configurations, during the transition from driven mode to oscillation mode, components of both modes may be enabled for some period to provide a hybrid mode. Referring to
In certain embodiments, the amplifiers 212, 214 can be replaced with other components to permit switching of the generator from the driven mode to an oscillation mode or operation of the generator in a hybrid mode. Referring to
In certain examples, a simplified schematic of certain components of a generator is shown in
In certain examples, induction devices suitable for use with the generators described herein may vary. In some embodiments, the induction device may comprises a load coil comprising a wire coiled a selected number of turns, e.g., 3-10 turns. The coiled wire provides RF energy into the torch to sustain the plasma. For example and referring to
In some embodiments, one or more plate electrodes may be electrically coupled to the generators described herein. In certain examples, the planar nature of the plate electrodes permits generation of a loop current in the torch body which is substantially perpendicular to the longitudinal axis of the torch body. The plate electrodes may be spaced symmetric from each other where more than two plate electrodes are present, or the plates electrodes may be asymmetrically spaced from each other, if desired. An illustration of two plate electrodes that can be electrically coupled to a generator to permit operation of the plate electrodes when the generator is in a driven mode and an oscillation mode is shown in
In certain embodiments, the generators described herein may be used in combination with another generator, which may be the same or may be different. For ease of illustration, block diagrams of several configurations are included herein. The term “single mode generator” refers to a generator which can operate in a driven mode or in an oscillation mode but is generally not switchable between the modes. Referring to
In certain examples, another system is shown in
In certain examples, another system is shown in
In certain embodiments where more than a single generator is present, each generator may be independently electrically coupled to one, two, three or more plate electrodes. Illustrations using two plate electrodes for convenience purposes are shown in
In certain embodiments, another system is shown in
In certain examples, another system is shown in
In certain embodiments where more than a single generator is present, one generator may be independently electrically coupled to one, two, three or more plate electrodes and the other generator may be electrically coupled to a load coil. Illustrations using two plate electrodes for convenience purposes are shown in
In certain examples, another system is shown in
In certain examples, another system is shown in
Referring to
In certain examples, another system is shown in
In certain examples, another system is shown in
In certain examples, a single hybrid generator as described herein may be used to provide power to two or more induction devices at the same time. Referring to
In certain embodiments, a similar system as shown in
In certain examples, a similar system as shown in
In certain examples, a similar system as shown in
In certain examples, the hybrid generators described herein can be used to power an inductively coupled plasma (ICP) that is present in an optical emission system (OES). Illustrative components of an OES are shown in
In certain embodiments, the generators described herein can be used in an instrument designed for absorption spectroscopy (AS). Atoms and ions may absorb certain wavelengths of light to provide energy for a transition from a lower energy level to a higher energy level. An atom or ion may contain multiple resonance lines resulting from transition from a ground state to a higher energy level. The energy needed to promote such transitions may be supplied using numerous sources, e.g., heat, flames, plasmas, arc, sparks, cathode ray lamps, lasers, etc., as discussed further below. In some examples, the generator described herein can be used to power an ICP to provide the energy or light that is absorbed by the atoms or ions. In certain examples, a single beam AS device is shown in
In certain embodiments and referring to
In certain embodiments, the generators described herein can be used in a mass spectrometer. An illustrative MS device is shown in
In certain embodiments, the mass analyzer 2630 of the MS device 2600 may take numerous forms depending on the desired resolution and the nature of the introduced sample. In certain examples, the mass analyzer is a scanning mass analyzer, a magnetic sector analyzer (e.g., for use in single and double-focusing MS devices), a quadrupole mass analyzer, an ion trap analyzer (e.g., cyclotrons, quadrupole ions traps), time-of-flight analyzers (e.g., matrix-assisted laser desorbed ionization time of flight analyzers), and other suitable mass analyzers that may separate species with different mass-to-charge ratio. In some examples, the MS devices disclosed herein may be hyphenated with one or more other analytical techniques. For example, MS devices may be hyphenated with devices for performing liquid chromatography, gas chromatography, capillary electrophoresis, and other suitable separation techniques. When coupling an MS device with a gas chromatograph, it may be desirable to include a suitable interface, e.g., traps, jet separators, etc., to introduce sample into the MS device from the gas chromatograph. When coupling an MS device to a liquid chromatograph, it may also be desirable to include a suitable interface to account for the differences in volume used in liquid chromatography and mass spectroscopy. For example, split interfaces may be used so that only a small amount of sample exiting the liquid chromatograph may be introduced into the MS device. Sample exiting from the liquid chromatograph may also be deposited in suitable wires, cups or chambers for transport to the ionization devices of the MS device. In certain examples, the liquid chromatograph may include a thermospray configured to vaporize and aerosolize sample as it passes through a heated capillary tube. Other suitable devices for introducing liquid samples from a liquid chromatograph into a MS device will be readily selected by the person of ordinary skill in the art, given the benefit of this disclosure. In certain examples, MS devices can be hyphenated with each other for tandem mass spectroscopy analyses.
In certain embodiments, the systems and devices described herein may include additional components as desired. For example, it may be desirable to include a photosensor in an optical path of the plasma so the system can detect when the plasma has been ignited. It may be desirable to switch from the driven mode to the oscillation mode as soon as the presence of the plasma is detected by the photosensor. In certain examples, the components of the generators described herein may be air cooled, liquid cooled or cooled with thermoelectric devices such as Peltier coolers. One or more fans may be present where air cooling. A chiller or circulator may be present to circulate a fluid through the system to absorb heat from the electronic components.
In some examples, the generators described herein can be used in non-instrumental applications including, but not limited to, vapor deposition devices, ion implantation devices, welding torches, molecular beam epitaxy devices or other devices or systems that use an atomization and/or ionization source to provide a desired output, e.g., ions, atoms or heat, may be used with the generators described herein. In addition, the generators described herein can be used in chemical reactors to promote formation of certain species at high temperature. For example, radioactive waste can be processed using devices including the generators described herein.
In certain examples, the generators described herein may be used to ignite a plasma in a torch body by providing power to an induction device from the generator in a driven mode, and switch the generator from the driven mode to an oscillation mode once the plasma is ignited. In some instances, the generator may remain in the driven mode for some period to power the induction device.
In certain embodiments, the generators described herein may be used in quality control application or in field service application to provide information regarding various components of the system. For example, a technician can use the generator as a means of determining which component(s) of the system may need replaced. In operation, torches and induction devices can fail from continued heat exposure, or electronic components may fail from overheating, overuse or other reasons. In some instances, a control signal (or signal of known amplitude, shape, waveform, etc.) can be provided in the driven mode of the generator and used to determine if the electronics of the generator are the cause of poor performance of the system. If the control signal detected represents an anticipated control signal, then the electronics may be removed as a cause of poor system performance. If desired, the control signal may be sent remotely by a technician so the technician can be provided remote feedback as to which of the components of the system may need replacing. For example, the control signal can be used to provide the technician information about the fidelity of the electronics, so they can take the desired components with them on a service call to repair the system.
In certain configurations, even though the hybrid generators described herein may be operated in a driven mode, an oscillation mode and a hybrid mode, an end user may operate the generator in only one of these modes. For example, the user may disable the driven mode and operate the generator exclusively in the oscillating mode. Similarly, the user may operate the generator exclusively in the driven mode or the hybrid mode if desired. Switching between the modes is not required for proper operation of an inductively coupled plasma or other suitable atomization/ionization device sustained using the hybrid generator, though depending on the conditions used switching between modes can provide better performance.
In certain instances, the generators described herein can be used to provide RF power to drive an induction device, e.g., load coil or other induction device, at one end. For example, a single-ended transistor, e.g., power transistor in the same phase, can be used to drive a load coil at one end of the load coil and the other end of the load coil may be grounded. Where two or more induction devices are present, one may be driven differentially by a pair of transistors in opposite polarities, e.g., out of phase, and the other may be driven by a power transistor to drive the load coil at one end. Any of the various induction devices and configurations described herein may use the single-ended design where the load coil is driven at one end by the generator.
Certain specific examples are described below to illustrate further some of the novel aspects, embodiments and features described herein.
A circuit was constructed as shown in
After the plasma was ignited and a desired voltage level is detected using the RF detector 2770, the generator was switched from the driven mode to the oscillation mode as shown in
The generator of Example 1 was used in combination with a single quadrupole mass filter spectrometer to measure the peak shapes of various elements. A copper load coil from a NexION instrument was used as the induction device. The other components of the NexION system were also used to perform the measurements. A frequency of 40 MHz was used.
The hybrid generator was imbalanced to test its stability. The null point (virtual ground was electronically moved along the load coil by unbalancing the driven differential signal amplitude and phase at 34.44 MHz using the processor. Phase balance can affect sensitivity, including the oxide ratio, and amplitude balance can also affect sensitivity. The various phases used at different times are shown in
The best signal was observed when the generator was differentially driven (0, 180 degrees) with a phase mirror within about 5 degrees (see top two curves in
The measurements performed in Example 2 were repeated using slightly different frequencies. The results are shown in the table of
When introducing elements of the examples disclosed herein, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including” and “having” are intended to be open-ended and mean that there may be additional elements other than the listed elements. It will be recognized by the person of ordinary skill in the art, given the benefit of this disclosure, that various components of the examples can be interchanged or substituted with various components in other examples.
Although certain aspects, examples and embodiments have been described above, it will be recognized by the person of ordinary skill in the art, given the benefit of this disclosure, that additions, substitutions, modifications, and alterations of the disclosed illustrative aspects, examples and embodiments are possible.
This application is related to, and claims priority to, U.S. Provisional Application No. 61/894,560 filed on Oct. 23, 2013, the entire disclosure of which is hereby incorporated herein by reference for all purposes.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4818916 | Morrisroe | Apr 1989 | A |
| 6222186 | Li | Apr 2001 | B1 |
| 7459899 | Mattaboni | Dec 2008 | B2 |
| 7678339 | Wira | Mar 2010 | B2 |
| 8624502 | Rosenthal | Jan 2014 | B2 |
| 20060017388 | Stevenson | Jan 2006 | A1 |
| 20120277739 | Daw | Nov 2012 | A1 |
| Entry |
|---|
| ISR/WO for PCT/US14/61682 mailed on Mar. 13, 2015. |
| Number | Date | Country | |
|---|---|---|---|
| 20150108898 A1 | Apr 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61894560 | Oct 2013 | US |
