Mass Spectrometer RF Choke With Lattice Winding for Fast DC Switching
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Solution Overview
Problem
Existing RF blocking filters in mass spectrometers exhibit high power dissipation, bulky size, and slow settling times, affecting the ability to achieve fast DC voltage changes, which is crucial for efficient ion transfer and analysis.
Innovation Solution
A compact RF choke with a bobbin, windings, and a magnetic core is designed to provide high impedance at RF frequencies and low impedance at DC frequencies, featuring low power dissipation and fast settling times, allowing for efficient ion transfer and analysis in vacuum environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional RF blocking filters are used, then RF signals are blocked, but power dissipation is high and device size is bulky
Solution Approach 1:
The patent changes the operating parameters by designing the RF choke with a specific inductance value (at least 100 µH) and using a magnetic core with optimized permeability, allowing the filter to achieve high RF blocking performance with lower power dissipation and reduced size compared to traditional filters
Solution Approach 2:
The patent employs a composite structure combining a magnetic core material with high permeability and low loss tangent, wrapped with copper wire windings, and enclosed in a vacuum-tight housing. This composite design enables simultaneous achievement of low power dissipation, compact size, and effective RF blocking
2Loss of time
If traditional RF blocking filters are used, then RF signals are blocked, but settling time is slow
Solution Approach 1:
The patent optimizes the inductance parameter to at least 100 µH and selects a magnetic core with specific permeability characteristics, enabling the filter to achieve fast settling time (reducing transient response time) while maintaining low power dissipation through reduced resistive losses in the optimized winding structure
3Reliability
If higher impedance is used to block RF frequencies, then RF blocking improves, but DC voltage switching speed decreases
Solution Approach 1:
The patent carefully selects the inductance parameter (at least 100 µH) to achieve sufficient RF blocking impedance while minimizing the time constant (L/R) for DC voltage transitions. The magnetic core material is selected to provide high permeability for RF frequencies while maintaining low loss, enabling fast DC response
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 RF choke enables faster DC voltage switching, reducing ion trapping and crosstalk, and allows for concurrent use in multiple sections of the ion path, enhancing MRM throughput and analysis speed.
Implementation Method 1
a magnetic core disposed in said hollow channel of the bobbin
Implementation Method 2
a plurality of windings wrapped around the bobbin, each of said windings exhibiting a lattice winding pattern
Data Source
AI summary
A radio frequency (RF) choke for use in a mass spectrometer, comprising a bobbin having a hollow channel, a plurality of wire windings wrapped around said bobbin, each of said wire windings exhibiting a lattice winding pattern having about 1 to about 4 crossover per turn, and magnetic core disposed in said hollow channel of the bobbin.