Time of Flight Mass Spectrometer Ion Detector with Photodiode Array
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Solution Overview
Problem
Current Time of Flight mass spectrometers face limitations in distinguishing between single and multiple ion arrivals, leading to inaccurate signal intensity and arrival time measurements, and suffer from limited abundance sensitivity due to electronic noise and crosstalk, making them ineffective at high ion currents.
Innovation Solution
An ion detector system utilizing a single Micro Channel Plate (MCP) in conjunction with a photodiode array, where electrons are converted into photons and detected by a photodiode array, providing a high overall gain and improved abundance sensitivity, capable of processing high ion arrival rates without crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one bit TDC detector system is used, then efficient detection of weak signals is achieved, but the ability to distinguish between single and multiple ion arrivals is lost
Solution Approach 1:
The invention divides the detection system into multiple independent channels (e.g., 8 channels), where each channel processes ion arrival information separately. This segmentation allows the system to detect multiple ion arrivals simultaneously by recording which channels are triggered, thereby distinguishing between single and multiple ion events while maintaining efficient weak signal detection capability.
2Device complexity
If a fixed amplitude threshold is used for ion detection, then simple event recording is achieved, but accurate representation of signal intensity is lost
Solution Approach 1:
The invention transitions from a single-dimensional threshold-based detection to a multi-dimensional channel-based detection system. Instead of relying solely on amplitude threshold crossing, the system uses multiple parallel channels that can independently detect ion arrivals, adding a dimensional aspect to the detection that preserves signal intensity information through the pattern of channel activations.
3Quantity of substance
If ADC detector system is used, then multiple ion arrivals can be recorded at high signal intensities, but detection of low intensity signals is limited by electronic noise
Solution Approach 1:
By dividing the detection system into multiple channels, the invention enables simultaneous detection of multiple ion arrivals (handling high signal intensities) while maintaining low noise performance in each individual channel. The segmentation isolates electronic noise to each channel, preventing it from overwhelming low intensity signals, while the collective output of multiple channels captures high intensity events.
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
The system significantly enhances dynamic range and abundance sensitivity, enabling detection of 10^9 ion events per second with improved accuracy and reduced crosstalk, effectively handling bright ion sources.
Implementation Method 1
A ion detector for a Time of Flight mass spectrometer comprises a single Micro Channel Plate ("MCP")... which are arranged and adapted to convert ions into electrons
Implementation Method 2
an array of photodiodes... which are arranged and adapted to detect electrons and create a signal
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2~3
AI summary
An ion detector for a Time of Flight mass spectrometer is disclosed comprising a single Microchannel Plate 1 which is arranged to receive ions 2 and output electrons 3. The electrons 3 are directed onto a scintillator 9 and onto an array of photodiodes 4 which detects photons 11 generated from the electrons 3. The output from each photodiode 4 is connected to a separate Time to Digital Converter provided on an ASIC 5.