Ion Pump Cathode Impact Deflection for Longer Lifespan
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Solution Overview
Problem
Ion pumps in mass spectrometers have a limited lifespan due to cathode surface degradation from ion bombardment, which is particularly problematic in remote sensing applications where access and maintenance are difficult.
Innovation Solution
The ion pump system incorporates deflection plates and additional cathode material to alter the trajectory of accelerated ions, dispersing their impact on the cathode surface, thereby extending the cathode's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ions are accelerated directly to the cathode along the anode tube axis, then the ion pump achieves effective vacuum pumping, but the cathode surface degrades rapidly due to concentrated ion bombardment
Solution Approach 1:
The invention segments the ion impact area by introducing deflection plates that divide the concentrated axial ion beam into multiple dispersed trajectories. The deflection plates create separate impact zones on the cathode surface, distributing the ion bombardment load across multiple segments rather than concentrating it on a single central point, thereby extending cathode lifespan
Solution Approach 2:
The invention transitions from one-dimensional axial ion transport to two-dimensional or three-dimensional ion distribution by using deflection plates to steer ions onto angled trajectories. This dimensional change spreads ion impacts across a larger surface area of the cathode, reducing the concentration of degradation at any single point
2Duration of action of stationary object
If the cathode surface is concentrated in a small area, then the ion pump structure is compact, but the cathode lifespan is limited due to rapid material depletion
Solution Approach 1:
The cathode surface is effectively segmented into multiple impact zones through the action of deflection plates. Each zone receives a portion of the ion flux, allowing the total cathode surface area to be larger while maintaining a compact overall structure. This segmentation enables extended cathode lifespan by distributing material depletion across multiple regions
3Duration of action of stationary object
If deflection plates are added to alter ion trajectories, then cathode lifespan is extended, but the device complexity increases
Solution Approach 1:
The deflection plates serve multiple functions simultaneously: they deflect ions from the axial trajectory, distribute ion impacts across the cathode surface, and can be integrated into the existing anode tube structure. This multi-functionality extends cathode lifespan while minimizing the increase in device complexity by making the added components serve several purposes
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 approach triples the cathode's lifespan by distributing the ion impact over a wider area, reducing the rate of cathode degradation and preventing vacuum breaches.
Implementation Method 1
The plurality of deflection plates may be configured to steer a trajectory of an accelerated ion off the mechanical center axis of the anode tube
Implementation Method 2
The ion pump may achieve vacuum by ionizing molecules that drift into a cylindrical anode, then driving them to a cathode surface using an electric field
Implementation Method 3
driving them to a cathode surface using an electric field
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
Within an ion pump, accelerated ions leave the center portion of an anode tube (200; 300; 400; 500; 600; 610) due to the anode tube symmetry and the generally symmetrical electric fields present. The apparent symmetry within the anode tube (200 ... 610) may be altered by making the anode tube longitudinally segmented and applying independent voltages to each segment. The voltages on two adjacent segments may be time varying at different rates to achieve a rasterizing process. In various embodiments, one or more wire internal to the anode structure and having a time-varying electric potential may alter the trajectory of the ions leaving the anode tube (200 ... 610), as may the shape of the anode near the ends of the anode tube (200 ... 610).