Time-of-Flight Mass Spectrometer Pulse Timing Control
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Solution Overview
Problem
The existing time-of-flight mass spectrometers face a challenge in maintaining high mass accuracy due to temporal fluctuations in the rising high-voltage pulse caused by changes in measurement periods, leading to time discrepancies and mass inaccuracies.
Innovation Solution
A time-of-flight mass spectrometer with a high-voltage pulse generator that includes a controller to adjust the voltage applied between the transformer's primary winding, ensuring a consistent pulse rise time across varying measurement periods by changing the primary-side power supply according to stored information, thereby minimizing temporal fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the measurement period is changed to adapt to different ions, then the adaptability of the mass spectrometer is improved, but temporal fluctuations in the high-voltage pulse rise time occur causing mass accuracy to deteriorate
Solution Approach 1:
The patent applies parameter changes by adjusting the primary-side voltage of the transformer according to the measurement period. When the measurement period changes, the controller modifies the voltage applied to the primary winding of the transformer, which compensates for the temporal fluctuations in the high-voltage pulse rise time caused by different measurement periods, thereby maintaining consistent ion ejection timing and mass accuracy across varying measurement conditions
Solution Approach 2:
The patent implements feedback control where the controller receives information about the measurement period and automatically adjusts the primary-side voltage accordingly. This closed-loop control system ensures that the high-voltage pulse timing remains consistent despite changes in measurement period, maintaining mass accuracy through automatic compensation
2Productivity
If a high-voltage pulse generator with transformer is used to generate short duration high-voltage pulses, then the productivity and measurement speed are improved, but temporal fluctuations in pulse timing occur when measurement period changes, worsening measurement precision
Solution Approach 1:
The patent maintains high measurement speed by using a transformer-based high-voltage pulse generator while compensating for timing fluctuations through parameter changes. The controller adjusts the primary-side voltage based on the measurement period, ensuring that the high-voltage pulse timing remains consistent across different measurement conditions, thereby maintaining both productivity and measurement precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures consistent timing of the high-voltage pulse application, maintaining high mass accuracy irrespective of measurement period changes, reducing mass discrepancies and simplifying the calibration process.
Implementation Method 1
an ion ejector for ejecting ions to be analyzed into a flight space by imparting acceleration energy to the ions by an effect of an electric field created by a voltage applied to an electrode
Implementation Method 2
a pulse transformer for transmitting the pulse signal from a control-system circuit to a power-system circuit while electrically insulating the control circuit that operates with a low voltage from the power circuit that operates with a high voltage
Data Source
Figure 1~2E
Figure 3
Figure 4~5
AI summary
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.