Shimadzu Corporation

Eizo Kawato

Shinichi Yamaguchi

Junichi Taniguchi

Toshiya Habu

The present invention is provided to reduce the distortion or delay of the input waveform of a high-speed analog signal due to the capacitance of a protection element inserted for the purpose of ESD protection in an input circuit for a high-speed analog signal, so as to determine the correct waveform of the high-speed analog signal. In an input protection circuit for a high-speed analog signal, a resistor is provided on a signal path connecting an input connector and an input circuit; a polymer ESD protection element is connected between a portion of the signal path, which extends from the resistor to the input connector, and the ground; a semiconductor ESD protection element is connected between a portion of the signal path, which extends from the resistor to the input circuit, and either the ground or power source; and the sum of the resistance value of an input resistor of the input circuit and the resistance value of the resistor is equal to the characteristic impedance of a high-speed analog signal input.

Input protection circuit for high-speed analogue signal and time-of-flight mass spectrometer

A high-frequency power supply apparatus for supplying high-frequency power to a load the impedance of which greatly fluctuates is provided, wherein a stable high-frequency current is always maintained without having overcurrent or overvoltage generated in a drive circuit thereof. In the high-frequency power supply apparatus, a constant-current conversion circuit is connected between an LCR series resonant circuit and a half-bridge drive circuit, high-frequency current of the LCR series resonant circuit is controlled by the voltage of the half-bridge drive circuit, and a constant-current function is applied to impedance variation of the load. Due to the constant-current conversion circuit, the gate of a MOSFET of the half-bridge drive circuit is driven with a parallel capacitor using a transformer inserted in the LCR series resonant circuit, and the phases of the high-frequency current of the LCR series resonant circuit and the output of the half-bridge drive circuit are maintained to be constant.

High-frequency power supply apparatus for supplying high-frequency power

An emission spectrophotometer capable of inhibiting non-uniformity of spectral intensities of component elements is provided. The emission spectrophotometer generates pulse light emission by supplying an energy accumulated in an electricity accumulating and discharging unit to a gap between an electrode and a test material, and the emission spectrophotometer includes a detection unit, for detecting an energy charged to the electricity accumulating and discharging unit before the pulse light emission; and a detection unit, for detecting an energy remaining in the electricity accumulating and discharging unit after the pulse light emission. It is determined whether the detected light is emitted by fully using the energy accumulated in the electricity accumulating and discharging unit.

Emission spectrophotometer

A time-of-flight measuring device for performing a hardware-based high-speed data compression process before transferring the data from a signal recorder to a data processor is provided. A time-series digital signal recorded by a signal recorder is converted to a plurality of time-series digital signals by being divided into a bit string including baseline information and a bit string not including the baseline information. Then, the time-series digital signal consisting of a bit string not including the baseline information is compressed by run-length encoding, such as zero length encoding or switched run-length encoding. Subsequently, static Huffman coding is performed on each of the time-series digital signals to reduce the data amount.

Time-of-flight measuring device

An optical emission analysis apparatus includes a discharge gap, an ignitor circuit, and a main discharge power supply. The ignitor circuit includes an ignition transformer, a pair of current control devices, and an excitation power supply. On a secondary coil of the ignition transformer, the discharge gap and the main discharge power supply are connected in series to form a main discharge current path. On a primary coil of the ignition transformer, the pair of current control devices and the excitation power supply are connected in series to form an excitation current path. A pair of current control devices is connected to each other via mutually opposite polarities. The polarity of the high voltage generated in the secondary coil is reversed by reversing the polarity of the voltage of the excitation power supply. The direction of the main discharge current is reversed by reversing the polarity of the voltage of the main discharge power supply. Through the reverse polarity discharge, the deposits on the electrode are removed.

Optical emission analysis apparatus

An optical emission spectrometry device is provided. In the optical emission spectrometry device, a discharge path is formed by connecting an ignition circuit to a discharge gap, and further connecting in parallel a plurality of sets of coils and driving circuits, each set having one coil and one driving circuit. Each driving circuit has two operation modes: an increasing operation mode of applying a predetermined potential difference to the corresponding coil of the set to increase the current passing through the corresponding coil, and a sustaining operation mode of directly connecting the corresponding coil of the set to the discharge path to sustain the current passing through the corresponding coil. Moreover, each driving circuit is controlled in such a way that the timing for the increasing operation mode in which the current passing through the coil increases alternates with the timing for the increasing operation mode of other driving circuit.

Optical emission spectrometry device

In the ion storage deviceaccording to the present invention, an LC resonant circuitfor generating an RF voltage for trapping ions is connected to at least one of the electrodesandsurrounding the ion storing space. The LC resonant circuitincludes switching devicesand resistancesfor stopping the RF voltage when the ions stored in the ion storing spaceare ejected. The inductance L, the capacitance C and the resistance R of the LC resonant circuit are set to substantially satisfy the critical damping condition, which means that R=X/2 where X=&#x3c9;L=(&#x3c9;C). According to this configuration, the RF voltage damps fast when the RF voltage is stopped by the switching devices, and the deterioration of the mass resolution of the mass analyzer or the peak shift in the mass spectrum is prevented.

Ion storage device

The method of the present invention is to select ions having a predetermined mass to charge ratio by applying an ion selecting electric field in an ion storage space of an ion storage device. The method is characterized in that the ion selecting electric field is generated to be proportional to a product of a) a base wave composed of a repetition of a unit wave of a constant amplitude and a predetermined pattern, and b) an amplitude pattern which changes continuously. The amplitude pattern is preferred to increase as time passes in order to gradually increase the intensity of the ion selecting electric field applied to the ion storage space until ions of a desired mass to charge ratio are selected. The unit wave may be generated by the FNF method or by the SWIFT method. Further, it is effective to increase the intensity of the frequency components of the unit wave as the frequency is further from the characteristic frequency of the object ion having a desired mass to charge ratio.

Method of selecting ions in an ion storage device

A mass analyzer includes: an ion trap device including an ion trapping space surrounded by a plurality of electrodes; a time-of-flight mass analyzer for determining a mass to charge ratio of ions ejected from the ion trapping space; a trapping voltage generator for generating an ion trapping RF voltage to at least one of the plurality of electrodes; an ejecting voltage generator for generating an ejecting voltage to at least one of the plurality of electrodes to form an ion ejection electric field for ejecting ions trapped in the ion trapping space; and a controller for stopping the ion trapping RF voltage at a timing when ions are trapped in the ion trapping space and the ion trapping RF voltage is at a predetermined phase, and for applying the ion ejecting voltage a predetermined period after the ion trapping RF voltage is stopped. Here the predetermined phase and the predetermined period are predetermined so that, when the ion trapping RF voltage is stopped at the predetermined phase and the predetermined period passes, the voltage of said at least one of the electrodes to which the ion trapping voltage is generated becomes almost a certain fixed value irrespective of the amplitude of the ion trapping RF voltage when it is stopped. Thus, by stopping the ion trapping RF voltage and applying the ion ejecting voltage at such a timing, the initial kinetic energy of the ejected ions does not vary with the amplitude of the ion trapping voltage before it is stopped, and a precise determination of the mass to charge ratio of the ions becomes possible.

Mass analyzer and mass analyzing method

In the mass spectrometer of the present invention, the controller controls the time of changing the voltage applied to the electrode or electrodes of the ion trap from the ion trapping voltage to the ion ejecting voltage according to the polarity of the electric charge of ions to be ejected from the ion trap. Since positively charged ions and negatively charged ions move in the same direction if the phases of the RF voltage for generating the ion trapping electric field in the ion trap are reversed, the controller may reverse the phase of the RF voltage for trapping ions according to the polarity of the electric charge of ions when the ion ejecting time is fixed, irrespective of the polarity of the electric charge of ions to be ejected. Alternatively, the controller may change the ion ejecting time by half a cycle of the RF voltage depending on the polarity of the electric charge of ions when the ion trapping RF voltage is maintained the same. Owing to such a control, the ions are ejected when they are converging or are converged in the ion trap irrespective of the polarity of the electric charge of the ions. This minimizes the variation in the starting point of ions ejected from the ion trap, and reduces errors in their flight time in the subsequent TOF-MS, whereby the accuracy of the mass analysis is improved and the mass resolution is enhanced.

Mass spectrometer with an ion trap

In an ion trap device including: a plurality of electrodes enclosing an ion trapping space for trapping ions; an RF driving circuit for generating an RF driving voltage; a resonant circuit for amplifying the RF driving voltage and applying an RF high voltage to at least one of the plurality of electrodes; and a tuning circuit for adjusting a resonant frequency of the resonant circuit while keeping the amplitude of the RF high voltage constant, the method of adjusting the ion trap device according to the present invention includes the steps of: adjusting a resonant frequency of the resonant circuit to a frequency of the RF driving voltage; and shifting the resonant frequency of the resonant circuit so that the RF driving voltage increases by a predetermined constant ratio. According to the ion trap device and its adjusting method of the present invention, the phase difference between the RF driving voltage of the RF driving circuit and the RF high voltage, &#x3b8;, is adjusted to the same value in plural devices even if the parameters of various elements constituting the resonant circuit, such as the inductance or the equivalent resistance, are slightly different from device to device. Thus the influence of the change in the resonant angular frequency &#x394;&#x3c9; when the amplitude of the RF high voltage is changed to the phase difference &#x3b8;, &#x394;&#x3b8;, is the same among devices, and the qualities, such as the mass resolution, of all the devices are always set at their optimal, even if the same parameter values are used to determine operation timings of the device.

Ion trap device and its adjusting method

An ion trap device, which is composed of a ring electrode and a pair of end cap electrodes, according to the present invention includes a capacitor for adjusting a capacitance between the ring electrode and one of the end cap electrodes so that a fluctuation in the voltage of the ring electrode is suppressed when an ion-ejecting voltage is applied to one or both of the pair of end cap electrodes and ions in the ion trap device are ejected. Instead of using a capacitor device, such an object can be realized by modifying a shape of one of the end cap electrodes. The fluctuation in the voltage of the ring electrode can be suppressed when high DC voltages are applied to the end cap electrodes to eject ions from the ion trap device. This enables endowing ejected ions having different mass to charge ratios with the same energy, which prevents the subsequent mass analyzer using the ejected ions from being influenced by the operation parameters, such as the ion-trapping RF voltage, of the ion trap device, and improves the performances, such as the mass resolution and the sensitivity, of the mass analyzer.

Ion trap device

A mass spectroscope includes an ion source for generating ions, a mass spectrometry portion, and an ion retention portion arranged between the ion source and mass spectrometry portion for storing, cooling and/or dissociating the ions before the ions are discharged into the mass spectrometry portion. The mass spectroscope further includes a flow adjusting device for adjusting a gas flowing into the ion retention portion from an outside, and a control device for controlling the flow adjusting device in order to appropriately set a gas pressure in the ion retention portion according to an operation mode such as an introducing operation, a retention operation, and a discharging operation.

Mass spectroscope and method for analysis

The resonance frequency of the resonant circuit, which is used to apply the RF high voltage to an electrode of the ion trap device, is deliberately shifted from the frequency of the RF driver (driving frequency). This reduces the influence of the deviation in the resonance frequency caused by the change in the RF high voltage on the shift in the phase difference between the output of the RF driver and the RF high voltage. This minimizes the degradation of various performances of the ion trap device relating to the phase difference, such as the shift in the peaks of the mass spectrum, and enhances the precision and sensitivity of the mass analysis of the mass spectrometers using the ion trap device.

Ion trap device and its tuning method

The present invention proposes a time-of-flight mass spectrometer having an ion reflector, which can detect the ions over a wider range of energy while maintaining the resolution, thus improving the ion detection sensitivity by a simple method. In the time-of-flight mass spectrometer, the ion reflector has plural thin plate electrodes and a final electrode. Appropriate voltages are applied to the electrodes so as to construct a first stage with a substantially uniform high electric field strength and a second stage with a substantially uniform low electric field strength. The electric field strength of the second stage is corrected so that it substantially increases at the side of the final electrode.

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Kyoto-fu, Japan

Eizo Kawato