Miniaturized X-Ray Source Using UV LED and Photocathode
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Solution Overview
Problem
Current X-ray sources lack the ability to rapidly and arbitrarily vary X-ray output intensity and energy, leading to reduced sensitivity in detectors due to background noise, large size, high cost, and instability, limiting their applications in medical imaging, materials science, and space exploration.
Innovation Solution
A miniaturized high-speed modulated X-ray source using an ultraviolet emitter, photocathode, electron multiplier, and anode to produce X-rays with adjustable intensity and energy on nanosecond timescales, eliminating the need for filaments and reducing size and cost by using metal photocathodes and high-gain electron multipliers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional X-ray sources are used to provide sufficient X-ray flux, then the X-ray output intensity is adequate, but the size and input power needs are too large to allow portability
Solution Approach 1:
The patent replaces conventional thermal filament-based X-ray generation with a photoelectric emission system using UV LED excitation. This substitution enables miniaturization while maintaining sufficient X-ray flux output, as the photoelectric process is more efficient and requires less power than thermal emission methods.
Solution Approach 2:
The patent changes the operational parameters by using pulsed UV LED excitation instead of continuous thermal heating. This allows precise control of electron emission timing and intensity, enabling portable operation while achieving the required X-ray flux through optimized pulse duration and intensity parameters.
2Reliability
If continuous X-ray emission is used to maintain calibration, then detector calibration is maintained, but detector sensitivity is reduced due to background noise
Solution Approach 1:
The patent implements periodic pulsed emission of X-rays synchronized with detector integration cycles. The UV LED excites the photocathode in controlled pulses, producing X-rays only during specific time windows when the detector is ready to measure, eliminating continuous background noise while maintaining calibration through regular pulsed operation.
3Productivity
If high-efficiency photocathodes are used to increase electron emission, then electron yield is improved, but stability deteriorates due to oxygen exposure and dark current
Solution Approach 1:
The patent uses aluminum photocathodes with moderate quantum efficiency combined with high-power UV LED excitation. This partial action approach avoids the stability problems of high-efficiency photocathodes while achieving sufficient electron emission through excessive UV photon flux, thereby maintaining productivity without sacrificing reliability.
4Ease of operation
If conventional X-ray sources are used to provide arbitrary intensity variation, then intensity control is achieved, but the response time is too slow for high-speed modulation
Solution Approach 1:
The patent replaces thermal filament control with electronic UV LED modulation and photoelectric emission. This substitution enables nanosecond-timescale intensity modulation because UV LED response time and photoelectron emission are inherently much faster than thermal heating and filament evaporation processes.
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
Enables precise dose control in medical imaging, high-contrast imaging, and efficient communication systems with reduced power consumption, while maintaining detector sensitivity and reducing unwanted X-ray production, making it suitable for various applications including medical, communication, and materials analysis.
Implementation Method 1
an ultraviolet emitter that emits ultraviolet light, a photocathode operably coupled to the ultraviolet light-emitting diode that emits electrons
Implementation Method 2
an electron multiplier operably coupled to the photocathode that multiplies incident electrons
Implementation Method 3
an anode operably coupled to the electron multiplier that is configured to produce X-rays
Data Source
AI summary
A miniaturized high-speed modulated X-ray source (MXS) device and a method for rapidly and arbitrarily varying with time the output X-ray photon intensities and energies. The MXS device includes an ultraviolet emitter that emits ultraviolet light, a photocathode operably coupled to the ultraviolet light-emitting diode that emits electrons, an electron multiplier operably coupled to the photocathode that multiplies incident electrons, and an anode operably coupled to the electron multiplier that is configured to produce X-rays. The method for modulating MXS includes modulating an intensity of an ultraviolet emitter to emit ultraviolet light, generating electrons in response to the ultraviolet light, multiplying the electrons to become more electrons, and producing X-rays by an anode that includes a target material configured to produce X-rays in response to impact of the more electrons.