Dual TDC-ADC Detector for Time of Flight Mass Spectrometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Time of flight mass spectrometry systems face challenges in accurately determining ion intensities due to limitations in timing resolution and dynamic range, particularly when dealing with high ion fluxes and varying ion intensities, as existing digital converters either sacrifice timing resolution for dynamic range or vice versa.
Innovation Solution
A dual TDC-ADC detection system is employed, where a higher timing resolution digital converter handles low intensity ions and a lower timing resolution digital converter handles high intensity ions, with the two converters operating in tandem to extend the dynamic range beyond what either could achieve individually, by using a processor to combine their data streams and determine ion intensities for each mass to charge ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single digital converter is used to measure ion intensities, then timing resolution or dynamic range can be optimized, but the other parameter is limited
Solution Approach 1:
The detection system is divided into two separate digital converters: a first digital converter optimized for high timing resolution to measure low intensity ions, and a second digital converter optimized for high dynamic range to measure high intensity ions. This segmentation allows each converter to specialize in a specific intensity range, resolving the contradiction between timing resolution and dynamic range by distributing these competing requirements across separate measurement channels.
Solution Approach 2:
Different regions of the ion intensity distribution are measured with different converter characteristics. Low intensity ions are measured with the first converter that provides superior timing resolution, while high intensity ions are measured with the second converter that provides extended dynamic range. This local quality approach matches the measurement capability to the specific requirements of each intensity region.
2Quantity of substance
If high ion fluxes are measured, then more ions are detected, but timing resolution deteriorates due to peak multiplicity
Solution Approach 1:
The system segments the ion flux measurement task by intensity level. The first digital converter handles low intensity ions where timing resolution can be maintained, while the second digital converter handles high intensity ions where peak multiplicity would otherwise degrade timing resolution. This allows the system to measure high ion fluxes overall while preserving timing resolution for the portion of the flux that requires it.
Solution Approach 2:
The processor acts as an intermediary that receives data from both digital converters and combines them into a unified mass spectrum. It processes the high timing resolution data from the first converter and the high dynamic range data from the second converter, merging their complementary information to produce accurate intensity measurements across the full range of ion fluxes without the timing resolution degradation that would occur in a single converter system.
3Device complexity
If a single digital converter is used, then device complexity is reduced, but the ability to handle varying ion intensities is limited
Solution Approach 1:
Rather than using a single converter that must compromise between different performance requirements, the system segments the measurement function across two converters with different optimizations. This segmentation increases adaptability to handle varying ion intensities across a broader dynamic range, accepting increased device complexity as the necessary trade-off to achieve the enhanced versatility.
Solution Approach 2:
The combined detection system achieves multi-functionality by integrating two converters with different strengths. The first converter provides high timing resolution capability, while the second provides extended dynamic range capability. Together, they create a universal detection system that can accurately measure ions across the full spectrum of intensities, from low to high, making the system adaptable to various measurement conditions.
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 approach allows for improved timing resolution and extended dynamic range, enabling accurate measurement of ion intensities across a broader range of ion fluxes and intensities, enhancing the overall performance of time of flight mass spectrometry systems.
Implementation Method 1
Time of flight mass spectrometry (TOFMS) involves accelerating ions through a field-free drift chamber toward a detector by application of a short, high-intensity electric field of known strength. The electric field is applied to impart kinetic energy to all ions, such that the ion's particle velocity across the drift chamber depends on its m/z ratio.
Implementation Method 2
detecting ions contacting the detector to generate a sequence of detection signals
Data Source
AI summary
Dual TDC-ADC detection systems for time of flight mass spectrometry are disclosed herein. Detection systems based upon TDC generally provide higher timing resolution as opposed to detection systems based upon ADC. However, ADC generally provides increased dynamic range over TDC. By combining TDC and ADC into a tandem detector, and adjusting performance parameters of the respective converter types, the dynamic range of the dual TDC-ADC detection can be extended beyond what either detector type could have achieved individually. Composite time of flight mass spectra can be generated by aggregating individual mass spectra acquired from multiple time-of-flight extractions, and selecting the number of time-of-flight extractions to ensure overlap between the ADC and TDC dynamic ranges in the dual TDC-ADC detector system.