| 摘要 |
An ionized gas detector and an ionize gas detecting method are provided, which measure an ion current for positive and negative ions by detecting the ion current in a simple structure, thereby detects the concentration of a measuring-subject gas. The detector and method do not receive the effect of DC drift caused by a DC voltage applying method, and do not lose detection sensitivity even if electrodes are contaminated (even if insulate electrodes are used). An ionized gas detector (10) includes at least a pair of ion detecting electrodes (12) that detect ions of the ionized measuring-subject gas, an electrode-voltage applying means (14) that applies a given voltage to the ion detecting electrodes (12), the electrode-voltage applying means (14) being configured to be capable of reversing its voltage polarity, a charge amplifier circuit (16) having a charge capacitor (18) that accumulates electric charges generated by voltage application by the electrode-voltage applying means (14), an ion current calculating means (22) that calculates the value of an ion current of ions of the measuring-subject gas, based on a time-dependent change of the volume of electric charges accumulated in the charge capacitor (18) of the charge amplifier circuit (16), a concentration determining means (24) that determines the concentration of the measuring-subject gas, based on an ion current value calculated by the ion current calculating means (22), and a voltage polarity control means (26) that reverses the polarity of the electrode-voltage applying means (14) according to the volume of electric charges accumulated in the charge capacitor (18) of the charge amplifier circuit (16). |
