Triple Switch Topology for Ultrafast Polarity Switching in Mass Spectrometry
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Solution Overview
Problem
Existing time of flight mass spectrometry pulsers are slow in switching between polarities, leading to inefficiencies in analyzing ions of different polarities within a short time frame, as they rely on mechanical relays and large capacitors that are prone to failure and take significant time to charge and discharge.
Innovation Solution
A pulser system utilizing a combination of positive, negative, and bipolar switches, controlled by a system controller, to rapidly switch between polarities, allowing for the use of MOSFETs and transformers to ensure simultaneous activation and deactivation of switches, enabling fast polarity switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical relays and large capacitors are used in the pulser system, then the system can provide high voltage pulses, but the switching speed between polarities becomes slow
Solution Approach 1:
The patent replaces mechanical relay switches with electronic MOSFET switches. The mechanical relay system is substituted with solid-state MOSFET transistors that can switch polarity much faster (nanoseconds to microseconds compared to seconds for mechanical relays). This substitution resolves the contradiction by achieving both high switching speed and improved reliability through solid-state components.
Solution Approach 2:
The patent changes the capacitance parameter by replacing large capacitors with smaller capacitors in the circuit. By reducing the capacitor size, the charge and discharge time constants are reduced, enabling faster polarity switching. This parameter change allows the system to achieve rapid switching speeds while maintaining the necessary voltage pulse generation capability.
2Use of energy by moving object
If large capacitors are used to store energy for high voltage pulses, then sufficient energy can be delivered, but the charge and discharge time increases significantly
Solution Approach 1:
The patent reduces the capacitance value parameter in the energy storage circuit. By using smaller capacitors with lower capacitance values, the charge and discharge time constants (τ = RC) are reduced proportionally. This allows the system to maintain sufficient energy delivery capability through higher voltage or optimized switching while achieving much faster charge and discharge cycles, resolving the time loss issue.
Solution Approach 2:
The patent replaces the passive capacitor-based energy storage system with an active switching system using MOSFETs that can rapidly transfer energy. This substitution enables precise control over energy delivery timing and amount, allowing fast polarity switching without being constrained by large capacitor charge/discharge times.
3Device complexity
If mechanical relays are used for polarity switching, then the system structure is simple, but the switching frequency is limited
Solution Approach 1:
The patent replaces mechanical relay switches with electronic MOSFET switches controlled by a microcontroller. While this increases circuit complexity compared to simple mechanical relays, it enables switching frequencies in the nanosecond to microsecond range, dramatically improving productivity. The increased electronic control complexity is justified by the exponential gain in switching frequency capability.
4Ease of manufacture
If traditional pulser systems are used, then the design is straightforward, but the analysis time for both polarities cannot be shortened
Solution Approach 1:
The patent replaces traditional mechanical pulser design with an electronic MOSFET-based pulser system controlled by a microcontroller. This substitution enables rapid polarity switching that allows both positive and negative ion analysis to be performed within a single flight time window, dramatically reducing total analysis time while maintaining ease of manufacture through standard electronic components and control software.
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 achieves rapid polarity switching on the order of nanoseconds to microseconds, enabling the analysis of both positive and negative ions within a short time frame, matching or exceeding the speed of quadrupole mass spectrometers and overcoming the limitations of traditional pulsers.
Implementation Method 1
A pulser system utilizing a combination of positive, negative, and bipolar switches, controlled by a system controller, to rapidly switch between polarities, allowing for the use of MOSFETs and transformers to ensure simultaneous activation and deactivation of switches
Implementation Method 2
allowing for the use of MOSFETs and transformers to ensure simultaneous activation and deactivation of switches
Implementation Method 3
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
Implementation Method 4
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 5
Each ion's flight time across the field-free drift chamber to reach the detector, which is located a known distance from the ion source, is measurable
Data Source
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AI summary
There is provided a pulser, a time of flight mass spectrometer system comprising the same, and a method of analyzing the ions using the pulser. The pulser comprises a first positive switch for coupling and decoupling a first electrode of the accelerator assembly to a first positive voltage; a first negative switch for coupling and decoupling the first electrode to a first negative voltage; and, a first bipolar switch for alternately coupling and decoupling the first electrode to a third voltage.