X-ray Generator Cold Cathode Vacuuming with Tungsten Filament
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Solution Overview
Problem
Existing X-ray generators with cold cathodes face issues of deteriorated vacuum levels and corona discharge, leading to poor X-ray photo quality over time, and require lengthy vacuuming processes.
Innovation Solution
Incorporating a tungsten filament within the glass ball-tube to heat and accelerate electrons during the vacuuming process, combined with an insulating gel to prevent corona discharge, allowing for efficient and prolonged maintenance of high vacuum levels and improved X-ray photo quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional vacuuming process is used for cold cathode X-ray generator, then vacuum level can be reached, but vacuuming time is too long (about 3 hours) and vacuum level deteriorates after short use
Solution Approach 1:
The tungsten filament is heated before and during the vacuuming process to pre-clean the internal surfaces of the glass ball-tube. This preliminary heating action removes adsorbed gases and contaminants from the surface, creating a cleaner environment that maintains vacuum integrity for longer periods, thus reducing both vacuuming time and improving vacuum stability during operation.
Solution Approach 2:
The patent applies high voltage (several thousand to tens of thousands of volts) to the anode target during vacuuming to accelerate electrons and enhance the cleaning effect. This parameter change from conventional low-voltage vacuuming to high-voltage vacuuming dramatically reduces vacuuming time while improving the long-term stability of the vacuum level by more effectively removing contaminants.
2Productivity
If high voltage is applied during vacuuming, then vacuum level improves and time reduces, but corona discharge occurs at electrode pins
Solution Approach 1:
The insulating gel is introduced as an intermediary material between the electrode pins and the surrounding environment. This gel fills the space around the electrode pins and provides high electrical insulation, preventing corona discharge while allowing the high voltage to be effectively applied to the anode target for efficient vacuuming.
Solution Approach 2:
The insulating gel is applied locally around the electrode pins rather than throughout the entire device. This localized treatment addresses the specific problem of corona discharge at the electrode pins while maintaining the high voltage application efficiency for the vacuuming process elsewhere in the device.
3Use of energy by moving object
If thermionic cathode is used, then electron emission can be achieved, but 99% of electricity is transformed to heat requiring cooling water
Solution Approach 1:
The patent replaces the thermionic cathode (which relies on thermal energy to emit electrons) with a cold cathode system using field emission. This substitution eliminates the need for heating the cathode to high temperatures, thereby eliminating the requirement for cooling water while maintaining efficient electron emission through quantum mechanical field emission effects.
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 solution significantly reduces vacuuming time, maintains initial X-ray photo quality for thousands of shots, and prevents corona discharge, enabling continuous and low-dose X-ray generation with improved penetration and reduced device weight.
Implementation Method 1
a voltage is exerting on the single use pin to heat the tungsten
Implementation Method 2
the hot electrons emitting from the filament
Implementation Method 3
a high voltage is exerting on the anode target to accelerate the hot electrons emitting from the filament to bombard the inside wall of the glass ball-tube and the anode target
Implementation Method 4
an insulating gel having extremely high breakdown voltage resist avoiding corona discharge at the electrode pins
Data Source
AI summary
An encapsulated structure of an X ray generator with a cold cathode and method of vacuuming the same are disclosed. The X ray generator has a glass ball-tube having a base, a tungsten filament, a cold cathode, a focus cap, and an anode target inside, associated with a first electrode pin, a second electrode pin, a single-used pin, and anode pin extended out. The tungsten filament located at the periphery of the base has a first wire end connected with the second electrode pin and a second wire end connected with the single-used pin. While vacuuming the glass ball-tube before melting an end to seal, a voltage is exerting on the single use pin to heat the tungsten, and a high voltage is exerting on the anode target to accelerate the hot electrons emitting from the filament to bombard the inside wall of the glass ball-tube and the anode target so as to shorten the vacuuming time and increase the vacuum level.