Traveling Wave LINAC Pulse-to-Pulse Dosage Modulation
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Solution Overview
Problem
Conventional dual energy x-ray inspection systems using standing wave linear accelerators are prone to frequency and power jitter, leading to unstable beam energy and image artifacts, resulting in false positives and negatives during cargo inspection and radiotherapy applications.
Innovation Solution
A traveling wave linear accelerator (TW LINAC) is configured to modulate pulse-to-pulse intensity by varying the electron beam current, RF power, and frequency, ensuring energy stability and accuracy in generating x-rays for cargo scanning and radiotherapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standing wave LINAC is used for dual energy x-ray inspection, then material discrimination capability is improved, but beam energy stability deteriorates due to frequency and power jitter
Solution Approach 1:
The patent changes the operating parameters of the LINAC by switching between two different RF frequencies (e.g., 2856 MHz and 2998 MHz) to generate x-rays at two different energy levels. This parameter change enables dual-energy operation for material discrimination while maintaining beam stability through precise frequency control and synchronization of the RF system.
2Measurement precision
If x-ray intensity is varied to inspect dense cargo, then inspection accuracy is improved, but beam energy stability deteriorates
Solution Approach 1:
The patent employs periodic modulation of the electron beam current to vary x-ray intensity in a controlled manner. By using pulsed electron beams with adjustable duty cycles and repetition rates, the system can adapt intensity for different cargo densities while maintaining stable beam energy through synchronized RF frequency control and consistent acceleration conditions.
3Device complexity
If a single energy LINAC is used for cargo inspection, then device complexity is reduced, but inspection capability deteriorates due to inability to detect dense materials
Solution Approach 1:
The patent makes a single LINAC system universal by enabling it to operate at multiple energy levels through RF frequency modulation. The same accelerator structure and electron beam system can generate both low-energy and high-energy x-rays by changing the RF frequency, providing dual-energy inspection capability without requiring separate accelerators or complex additional components.
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 TW LINAC provides stable and accurate x-ray beams, reducing false identifications and enhancing the ability to homogeneously irradiate tumor volumes, thereby improving the effectiveness of cargo inspection and radiotherapy treatments.
Implementation Method 1
a beam of electrons accelerated by the LINAC
Implementation Method 2
These x-rays may be generated by directing the electron beams from the LINAC at an x-ray emitting target
Data Source
AI summary
Provided herein are systems and methods for operating a traveling wave linear accelerator to generate stable electron beams at two or more different intensities by varying the number of electrons injected into the accelerator structure during each pulse by varying the electron beam current applied to an electron gun. The electron beams may be used to generate x-rays having selected doses and energies, which may be used for cargo scanning or radiotherapy applications.