Multipole Ion Trap With DC Confinement for Compact Ion Cooling
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Solution Overview
Problem
Existing ion traps face challenges in efficiently cooling and confining ions without increasing the length of the cooled ion cloud, which can lead to ion scattering and fragmentation, and fail to match the spatial acceptance properties of mass analyzers.
Innovation Solution
The ion trap design incorporates first and second confining electrodes that apply repulsive DC potentials to create an ion confining region decoupled from the length of the multipole electrode assembly, allowing for increased cooling time without lengthening the ion trap and improving confinement of ions across a wider range of mass-to-charge ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the pressure in the ion trap is increased to cool ions, then ion cooling efficiency is improved, but ion scattering and fragmentation occur
Solution Approach 1:
The patent changes the parameter of ion trap pressure to optimize ion cooling. By operating at a specific pressure range (10^-3 to 10^-1 mbar), the system achieves effective ion cooling through collisions with buffer gas while avoiding the harmful effects of excessive pressure that would cause ion scattering and fragmentation.
2Duration of action of moving object
If the length of the ion trap is increased to provide more cooling time, then ion cooling time is improved, but the size of the cooled ion cloud increases
Solution Approach 1:
The patent changes the parameter of ion trap length to optimize the balance between cooling time and ion cloud size. By using a compact trap design with optimized electrode geometry, the system achieves sufficient ion cooling within a limited axial length, preventing the ion cloud from becoming too large for mass analyzer acceptance.
3Stability of the object's composition
If DC potentials are applied to end electrodes to confine ions, then axial confinement is improved, but ions require excessive cooling to be reflected by the potentials
Solution Approach 1:
The patent employs a composite confinement approach combining RF potentials applied to multipole electrodes for radial confinement with DC potentials applied to end electrodes for axial confinement. This composite electrode system creates an effective three-dimensional ion trap that confines ions without requiring excessive cooling, as the RF fields provide additional stabilizing potential.
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 design enhances ion confinement and cooling efficiency, reducing ion loss and fragmentation, while maintaining compatibility with mass analyzer spatial acceptance, particularly for high mass-to-charge ratio ions.
Implementation Method 1
The multipole electrode assembly is configured to confine ions to an ion channel when RF potentials are applied to the multipole electrode assembly
Implementation Method 2
The first and second confining electrodes are configured to receive a DC potential to confine ions within the ion channel when the DC potential is applied to the first and second confining electrodes
Implementation Method 3
ions confined within an ion trap cool to the central axis of the ion trap via collisions with a buffer gas, such as nitrogen or helium
Data Source
AI summary
The ion trap comprises a multipole electrode assembly, a first confining electrode, and a second confining electrode. The multipole electrode assembly is configured to confine ions of the first polarity to an ion channel extending in an axial direction of the multipole electrode assembly. The first confining electrode is provided adjacent to the multipole electrode assembly and extends in the axial direction of the multipole electrode assembly. The second confining electrode is provided adjacent to the multipole electrode assembly and extends in the axial direction of the multipole electrode assembly aligned with the first confining electrode. The first and second confining electrodes are spaced apart in the axial direction in order to define an ion confining region of the ion channel between the first and second confining electrodes. The first and second confining electrodes are configured to receive a DC potential of the first polarity to further confine ions within the ion channel in the ion confining region.