Anode Shield for Cold Cathode Ionization Gauge Electron Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cold cathode ionization vacuum gauges face issues with electron loss at the transition area from the anode post to the feedthrough insulator, leading to reduced sensitivity and linearity, especially at low pressures, due to the formation of conductive surfaces that attract electrons, causing discharge sustaining failures and non-linear responses.
Innovation Solution
An anode electrode shield is introduced to prevent electron loss by creating a repulsive electric field that keeps electrons away from the transition area, maintaining a pure electron plasma and improving sensitivity and linearity, while also protecting the feedthrough insulator from sputtered metal coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard feedthrough insulator design is used to support the anode, then the gauge structure is simple and easy to manufacture, but electrons are lost at the transition area to the insulator, reducing sensitivity and causing non-linear responses
Solution Approach 1:
A shield is introduced as an intermediary element between the anode and the feedthrough insulator. The shield creates a repulsive electric field that prevents electrons from reaching the insulator surface, thereby eliminating electron loss without requiring changes to the insulator design itself. This mediator approach resolves the contradiction by adding a protective element that improves measurement precision while maintaining structural simplicity.
Solution Approach 2:
The shield applies a preliminary repulsive electric field that counteracts the attractive force of the insulator surface before electrons can reach it. By establishing this anti-action in advance, the system prevents electron loss at the transition area, improving sensitivity and linearity without complicating the overall gauge structure.
2Adaptability or versatility
If the gauge operates at low pressures, then the measurement range is extended, but electron loss at the insulator becomes more significant, causing discharge sustaining failures
Solution Approach 1:
The shield acts as a mediator that protects the discharge plasma from electron loss to the insulator surface. By creating a repulsive electric field, the shield ensures that electrons remain confined to the discharge space even at low pressures, preventing discharge sustaining failures and extending the reliable operating pressure range.
Solution Approach 2:
The shield provides beforehand protection by establishing a repulsive electric field that cushions electrons from reaching the insulator surface. This prior cushioning effect prevents electron loss before it can occur, ensuring discharge sustainability across an extended pressure range including low pressure conditions.
3Device complexity
If electrons reach the feedthrough insulator, then the structure remains simple, but conductive surfaces form on the insulator, causing electron attraction and non-linear responses
Solution Approach 1:
The shield serves as a mediator that prevents electrons from reaching the feedthrough insulator. By creating a repulsive electric field, the shield stops the formation of conductive surfaces on the insulator, thereby maintaining response linearity without requiring modifications to the insulator structure itself.
Solution Approach 2:
The shield converts the potentially harmful effect of electron-insulator interaction into a beneficial configuration. By positioning the shield to create a repulsive field, the system uses the electric field geometry to prevent electron loss and maintain linearity, turning a structural simplicity advantage into a performance-enhancing feature.
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 shield enhances the gauge's sensitivity and linearity, extends its operational range to lower pressures, and increases its lifetime by minimizing sensitivity drift, ensuring a more reproducible response and reducing discharge sustaining issues.
Implementation Method 1
The shield is electrically isolated from the insulator and shields the insulator from electrons of the plasma
Implementation Method 2
A magnet applying a magnetic field through the discharge space to lengthen free electron paths to sustain the plasma
Implementation Method 3
An electric controller applies voltage between the anode and the cathode to create ionization with plasma discharge between the anode and the cathode
Data Source
AI summary
A cold cathode ionization gauge (CCIG) includes an extended anode, a cathode surrounding the anode along a length of the anode, and a feedthrough insulator supporting the anode. The cathode forms a discharge space around the anode to enable formation of a plasma between the anode and the cathode and a resultant ion current flow into the cathode. The CCIG further includes a magnet applying a magnetic field through the discharge space to lengthen free electron paths to sustain the plasma. A shield is electrically isolated from the insulator and shields the insulator from electrons of the plasma. The shield may be mounted to the cathode and surrounds and is spaced from the anode. An electric controller applies voltage between the anode and the cathode to create ionization with plasma discharge between the anode and the cathode, the controller determining pressure based on measured ion current flow to the cathode.