TIME-OF-FLIGHT MASS SPECTROMETER

• Main Author: MIZUTANI, Shiro
• Format: Patent
• Language: English; French; German
• Published: 27.11.2019
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

An acceleration voltage generator (7) generates a high-voltage pulse to be applied to a push-out electrode (11), by operating a switch section (74) to turn on and off a high direct-current voltage generated by a high-voltage power supply (75). A drive pulse signal is supplied from a controller (6) to the switch section (74) through a primary-side drive section (71), transformer (72), and secondary-side drive section (73). The measurement period of a repeated measurement is changed according to a target m/z range. A primary-voltage controller (61) controls a primary-side power supply (76) to change a primary-side voltage according to the measurement period, thereby adjusting the voltage to be applied between the two ends of a primary winding of the transformer (72) by the primary-side drive section (71). The pulse signal fed to the switch section (74) overshoots due to LC resonance. Due to this overshoot, the voltage at the point in time where the pulse signal begins to rise varies depending on the measurement period. Such a variation of the voltage at the point in time where the pulse signal begins to rise causes a discrepancy in the timing at which the rising slope crosses the threshold voltage of MOSFET. However, this discrepancy can be corrected by adjusting the primary-side voltage. As a result, high mass accuracy can be achieved irrespective of the measurement period.