Ion Detector Dual-Gain Splitting for Mass Spectrometer Dynamic Range
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Solution Overview
Problem
Current ion detector systems, particularly those using Time to Digital Converters and Analogue to Digital Converters, face limitations in dynamic range due to dead-time effects, inability to distinguish between single and multiple ion arrivals, and saturation issues, leading to inaccurate signal representation and measurement.
Innovation Solution
The method involves outputting two signals from an ion detector, each amplified by different gains, digitizing them, and combining the intensity and arrival time data to form a high dynamic range spectrum, while flagging and correcting for saturation events to avoid distortion and increase accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Time to Digital Converter is used to detect ion arrival events, then weak signals can be detected, but the dynamic range is limited due to dead-time effects and inability to distinguish single from multiple ion arrivals
Solution Approach 1:
The patent segments the detection process into multiple stages: initial threshold-based detection for weak signals, followed by secondary verification stages that analyze signal characteristics to distinguish single from multiple ion arrivals. This segmentation allows the system to maintain high sensitivity while extending dynamic range by handling different signal intensities through different processing paths.
Solution Approach 2:
The system dynamically changes detection parameters based on signal intensity. For weak signals, it uses lower thresholds and extended integration times. For stronger signals, it adjusts thresholds and employs multiple detection channels with different gain settings. This parameter adaptation allows the detector to maintain optimal performance across a wide dynamic range.
2Ease of operation
If a fixed amplitude threshold is used to trigger recording of ion arrival events, then simple detection is achieved, but multiple simultaneous ion arrivals cannot be distinguished from single ion arrivals
Solution Approach 1:
The patent introduces intermediary processing stages between the simple threshold trigger and the final detection output. These intermediaries include signal characteristic analyzers that examine multiple parameters (rise time, amplitude distribution, temporal profile) to distinguish single from multiple ion arrivals while maintaining the simplicity of the initial trigger mechanism.
Solution Approach 2:
The system transitions from one-dimensional amplitude-based detection to multi-dimensional signal analysis. By examining additional dimensions such as signal rise time, temporal profile, and amplitude distribution across multiple channels, the system can distinguish single from multiple ion arrivals while retaining the simplicity of threshold-based triggering.
3Adaptability or versatility
If an Analogue to Digital Converter is used to digitize ion detector signals, then multiple simultaneous ion arrivals can be recorded, but electronic noise limits the detection of low intensity signals
Solution Approach 1:
The patent merges multiple detection approaches: it combines the multi-ion detection capability of ADC-based systems with the low-noise advantages of TDC-based systems. By integrating signal processing techniques from both approaches and combining data from multiple detection channels, the system achieves both multi-ion detection capability and sensitivity to low intensity signals.
Solution Approach 2:
The system implements feedback mechanisms where detected signal characteristics inform subsequent detection parameters. Low intensity signals trigger adaptive noise filtering and integration techniques, while the system continuously adjusts detection thresholds and processing parameters based on real-time signal quality assessment, thereby maintaining sensitivity across varying signal intensities.
4Measurement precision
If signal averaging is used to improve low intensity signal detection, then noise is reduced, but the detection time increases and dynamic range remains limited
Solution Approach 1:
The patent implements dynamic signal processing where the degree of averaging and integration is adjusted in real-time based on signal intensity and quality. For weak signals, more extensive averaging is applied. For stronger signals, processing is accelerated. This dynamic adaptation reduces detection time while maintaining sensitivity improvements from averaging.
Solution Approach 2:
The system performs preliminary signal enhancement and noise filtering before full detection and processing. By pre-processing signals with adaptive filtering and selective integration based on initial quality assessment, the system reduces the time needed for subsequent full analysis while maintaining the noise reduction benefits of averaging.
Data Source
AI summary
A mass spectrometer is disclosed wherein an ion signal is split into a first and second signal. The first and second signals are multiplied by different gains and are digitized. Arrival time and intensity pairs are calculated for both digitized signals and the resulting time and intensity pairs are combined to form a high dynamic range spectrum. The spectrum is then combined with other corresponding spectra to form a summed spectrum.