Horn-Coupled THz Accelerator for Compact Electron Injection
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Solution Overview
Problem
Conventional charged particle accelerators face limitations in efficiency, size, and complexity, particularly when operating with ultrashort pulses, and existing THz accelerators are constrained by bandwidth limitations, making them unsuitable for compact and efficient electron acceleration.
Innovation Solution
The development of an accelerator apparatus with a horn-shaped coupling device and a non-resonant waveguide capable of focusing single cycle THz or RF pulses, allowing for broadband operation and efficient acceleration of charged particles by adapting the horn coupler and waveguide for broadband focusing and transmission, enabling the use of short pulses without bandwidth limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional single mode waveguides are used for THz pulse acceleration, then the structure is simple and operates at a central frequency, but the bandwidth is limited and ultrashort pulses cannot be effectively utilized
Solution Approach 1:
The waveguide structure is divided into multiple sections with different geometries (tapered section, constant width section, output section) to achieve broadband operation. Each section is optimized for specific functions: the tapered section provides impedance matching across a wide frequency range, while the constant width section maintains field confinement. This segmentation allows the waveguide to handle ultrashort THz pulses with broad spectral content without requiring a complex resonant structure.
Solution Approach 2:
The waveguide employs a tapered geometry that dynamically adapts the cross-sectional dimensions along the propagation direction. The width transitions from a larger input dimension to a smaller output dimension, creating a continuous impedance transformation that accommodates the broad frequency spectrum of ultrashort pulses. This dynamic geometric variation enables broadband operation without sacrificing structural simplicity.
2Adaptability or versatility
If the waveguide is designed for resonant operation at a central frequency, then the structure is optimized for that specific frequency, but it is not suitable for ultrashort broadband pulses
Solution Approach 1:
Instead of designing a resonant waveguide optimized for a single central frequency, the invention inverts the approach by creating a non-resonant waveguide specifically optimized for broadband ultrashort pulses. The design prioritizes impedance matching and field confinement across a wide frequency range over resonance at a specific frequency, making it inherently suitable for ultrashort pulse operation where the entire pulse spectrum must be transmitted simultaneously.
3Volume of moving object
If conventional electron guns are miniaturized by increasing operation frequency, then the size is reduced, but the damage threshold becomes the limiting factor
Solution Approach 1:
The accelerator uses periodic THz pulses with durations in the picosecond range to accelerate electrons through a compact structure. The periodic nature of the pulsed operation allows the use of lower average power while maintaining high peak fields necessary for compact acceleration. This periodic pulsed regime enables miniaturization without exceeding the damage threshold of the waveguide structures, as the duty cycle is sufficiently low to allow thermal dissipation between pulses.
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 enhances the acceleration efficiency, reduces the size of accelerators, and allows for high acceleration gradients, overcoming the limitations of conventional systems by effectively guiding single cycle pulses to achieve compact and efficient electron acceleration.
Implementation Method 1
The at least one horn coupler is adapted for incoupling pulsed radiation at the input aperture and focusing the pulsed radiation along a longitudinal beam direction towards the output aperture
Implementation Method 2
The waveguide device is connected to the output aperture(s) of the at least one horn coupler, and it is adapted for receiving the focused pulsed radiation
Implementation Method 3
the injection section, which is configured for providing a bunch of charged particles at an acceleration point and for subjecting the charged particles to an acceleration by the pulsed radiation travelling in the waveguide device
Data Source
AI summary
Accelerator apparatus (100) for accelerating charged particles (2) with pulsed radiation includes horn-shaped coupling device (10) with at least one horn coupler (11, 15) having input aperture (12), electrically conductive walls (13) and output aperture (14), wherein pulsed radiation is received at input aperture and focused towards output aperture, and waveguide device (20) coupled with the output aperture and configured for receiving focused pulsed radiation. Waveguide device includes injection section (21) for providing charged particles and subjecting them to acceleration by pulsed radiation in injection section, and lateral output port (23) for releasing accelerated charged particles along particle acceleration direction. The at least one horn coupler receives linearly polarized single cycle pulses (1) including broadband frequency spectrum shaped as a linearly polarized plane wave and focuses linearly polarized single cycle pulses. Waveguide device has non-resonant broadband transmission characteristic. Furthermore, charged particle gun and method of accelerating charged particles are described.