Time-of-Flight Mass Spectrometer High-Voltage Pulse Generator Jitter Reduction
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Solution Overview
Problem
Conventional time-of-flight mass spectrometers face significant temporal discrepancies in high-voltage pulse generation due to temperature fluctuations and signal jitter, leading to reduced mass resolution in integrated mass spectra.
Innovation Solution
A time-of-flight mass spectrometer with a high-voltage pulse generator that includes a direct-current power supply, a switch circuit with semiconductor switching elements, and a drive signal generator that outputs primary and secondary drive signals with a delay, minimizing jitter by charging or discharging the switching element's control terminal to maintain precise timing for ion ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional high-voltage pulse generator is used, then the device complexity is reduced, but temporal fluctuations in high-voltage pulse generation increase, leading to reduced mass resolution
Solution Approach 1:
The drive signal generator is segmented into multiple independent units: a primary drive signal generator and a secondary drive signal generator. The primary generator creates the initial drive signal, while the secondary generator creates a delayed version. This segmentation allows precise control over the timing and duration of the high-voltage pulse by independently adjusting each generator's parameters, thereby reducing temporal fluctuations and improving mass resolution.
Solution Approach 2:
The primary drive signal generator produces the drive signal in advance, and this signal is then fed into the secondary drive signal generator which adds a precise delay. This preliminary action ensures that the timing of the high-voltage pulse is pre-calculated and controlled before actual ion ejection, minimizing temporal jitter and improving measurement precision.
2Reliability
If temperature compensation is implemented, then temporal stability improves, but device complexity increases
Solution Approach 1:
The dual-generator system inherently compensates for temporal instability through its own architecture. The primary and secondary generators work together to maintain consistent timing, with the secondary generator's delayed signal providing a reference that automatically corrects for drift without requiring external temperature sensors or compensation circuits.
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 configuration significantly reduces temporal fluctuations in high-voltage pulse generation, ensuring accurate timing alignment between ion ejection and measurement initiation, thereby enhancing mass-to-charge ratio accuracy and mass resolution.
Implementation Method 1
a switching element drive unit for charging or discharging a capacitance of a control terminal of the semiconductor switching element according to a drive signal
Implementation Method 2
a pulse transformer 72 for transmitting a 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
Implementation Method 3
an ion ejector for ejecting ions to be measured 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
Data Source
AI summary
An acceleration voltage generator is configured to cause a power MOSFET to turn on or off to switch a high direct-current voltage, so as to generate a high-voltage pulse for an ejection of ions from an ion ejector. A drive signal is used to cause the power MOSFET to turn on, and further includes a secondary drive signal to recharge a gate capacitance to cause the power MOSFET to stay in an on-state. In a drive signal generator, edge detection circuits generate an edge detection signal based on a start signal; selection circuits generate a primary drive signal by adjusting the edge detection signal in its signal width; and a secondary drive signal generator includes multiple circuit elements such as a semiconductor element, and generates the secondary drive signal.