Channel Electron Multiplier Tapered Opening Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing channel electron multipliers in mass spectrometers suffer from reduced detection sensitivity due to voltage loss and disturbance of the electrostatic field in tapered openings, leading to inefficient electron multiplication and detection efficiency.
Innovation Solution
A channel electron multiplier with a tapered opening structure, where the input-side conductive layer continuously covers the input end face and part of the channel inner wall, and an electrode is placed at the output end face, set to the same potential as the input-side conductive layer, to minimize voltage loss and shield external electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a tapered opening is provided at the input side end of the channel to increase the detectable area, then the area of the channel opening is improved, but the electrostatic field in the tapered opening is disturbed by external electric fields and voltage drop occurs, reducing detection sensitivity
Solution Approach 1:
The patent applies equipotentiality by setting the electrode and input-side conductive layer to the same potential. This creates an equipotential region that prevents voltage drop in the tapered opening and eliminates disturbance of the electrostatic field by external electric fields, thereby maintaining detection sensitivity while preserving the enlarged channel opening area.
Solution Approach 2:
The patent introduces an electrode as an intermediary element disposed on the opposite side of the output end face with respect to the input end face. This electrode, having at least one opening through which charged particles pass, acts as a mediator to shield the tapered opening from external electric fields while allowing ion transmission, thus resolving the contradiction between area expansion and sensitivity maintenance.
2Productivity
If the tapered opening is exposed to external electric fields, then the channel opening area is maximized for ion reception, but electron multiplication efficiency decreases due to voltage loss and field disturbance
Solution Approach 1:
By establishing equipotential conditions between the electrode and input-side conductive layer, the patent eliminates voltage loss in the tapered opening region. This allows the channel opening to be maximized for ion reception without suffering from voltage drop that would otherwise reduce electron multiplication efficiency.
Solution Approach 2:
The electrode serves as an intermediary shielding structure that blocks external electric fields from distorting the electrostatic field in the tapered opening. This intermediary element enables the channel to maintain both large opening area for high ion reception capacity and stable voltage distribution for efficient electron multiplication.
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 configuration enhances detection sensitivity by maintaining a stable electrostatic field and maximizing electron multiplication, resulting in improved detection efficiency and sensitivity, potentially quadrupling the detection efficiency compared to previous designs.
Implementation Method 1
A first resistance layer and a first electron emission layer are formed on an inner wall surface of a channel
Implementation Method 2
the disturbance of the electrostatic field in the tapered opening is caused by the permeation of the external electric field
Data Source
AI summary
A CEM and an ion detector of one embodiment have a structure for enabling ion detection with higher sensitivity than the prior art. A channel electron multiplier includes a channel body, an input-side conductive layer, an output-side conductive layer, and an electrode. The channel body includes a channel, and a resistance layer and an electron emission layer formed on the channel's inner wall surface. The input-side conductive layer is provided on the channel body, and a part thereof extends into the tapered opening. The output-side conductive layer is provided on the tapered opening. The electrode has openings through which charged particles pass, and is disposed on an opposite side of the output end face to the input end face. The electrode and the input-side conductive layer are set to the same potential to eliminate the influence of an external electric field in the tapered opening.