Suspended Diamond Electron Source for SRF Accelerator Thermal Management
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Solution Overview
Problem
Conventional electron injection systems in superconducting radiofrequency (SRF) accelerators face challenges with localized heating leading to quench zones and reduced efficiency due to electron emission processes, which affect the superconductivity of the cavity wall and result in shutdowns, especially at high bunch charge and frequency.
Innovation Solution
A charge gating diamond QED based electron source is suspended within the RF cavity, using boron filaments and light guides to transmit photons synchronized with the RF field for electron emission, ensuring efficient heat dispersion and low electron beam emittance, and employing a diamond structure with high thermal conductivity and negative electron affinity for reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electron injection systems are used in SRF accelerators, then electron emission can be achieved, but localized heating occurs leading to quench zones and reduced superconductivity
Solution Approach 1:
The electron source is extracted from the conventional cavity wall mounting and suspended within the RF cavity volume using dielectric supports. This extraction removes the electron emission process from direct contact with the superconducting cavity wall, preventing localized heating at the wall while maintaining electron emission functionality in the cavity center
Solution Approach 2:
Dielectric support structures serve as intermediaries to suspend the electron source within the RF cavity. These supports mechanically connect the electron source to the cavity while electrically isolating it, enabling heat dissipation into the cryogenic environment without direct thermal contact with the superconducting wall
2Temperature
If electron source is mounted on cavity wall, then structural support is simple, but heat dissipation is poor causing quench zones
Solution Approach 1:
Dielectric support structures function as intermediaries that provide mechanical suspension while enabling thermal management. The supports conduct heat from the electron source into the cryogenic RF cavity environment without compromising the superconducting cavity wall, thus improving heat dissipation while adding controlled structural complexity
Solution Approach 2:
The system changes the thermal parameters by suspending the electron source in the cold RF cavity environment rather than mounting on the wall. This parameter change allows heat to dissipate into the cryogenic volume (4K environment) rather than being confined to the wall, preventing quench zones while maintaining structural integrity
3Productivity
If high bunch charge and frequency are used, then productivity increases, but localized heating worsens causing shutdowns
Solution Approach 1:
By extracting the electron source from wall mounting and suspending it in the RF cavity volume, the system can operate at high bunch charge and frequency without the localized heating problem that causes shutdowns. The separation allows heat to dissipate into the large cryogenic volume rather than concentrating at the wall, enabling continuous high-productivity operation
Solution Approach 2:
The invention converts the harmful localized heating effect into a beneficial distributed heat dissipation process. By suspending the electron source in the RF cavity, the heat that would previously cause quench zones is now dissipated into the cryogenic environment, turning a reliability problem into an efficient thermal management solution that enables high-productivity operation
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 configuration prevents quench zones, maintains high superconductivity, and achieves low electron beam emittance, enhancing the reliability and efficiency of electron injection systems, particularly in high-frequency applications like FEL drivers.
Implementation Method 1
diamond structure with high thermal conductivity
Implementation Method 2
diamond structure with high thermal conductivity and negative electron affinity for reliable operation
Implementation Method 3
one or more light guides configured to transmit photons from a photon source external the RF cavity to a back plane of the electron source, thus causing electron emission from the electron source
Implementation Method 4
a periodic electric field in the RF cavity causes electron beam emission from a front surface of the electron source opposite of the back plane of the electron source
Data Source
AI summary
Disclosed below are representative embodiments of methods, apparatus, and systems for generating electrons. For example, certain embodiments comprise a charge gating diamond QED based electron source, which can be suspended within the RF cavity of an electron injection system in a superconducting radiofrequency (SRF) electron accelerator. Embodiments of the disclosed technology are capable of producing low temperature (cold) electron beams, where “temperature” refers to the transverse energy in the extracted electron beam (or beam emittance). Embodiments of the disclosed technology can also exhibit enhanced charge replenishment capabilities by virtue of the material selected to suspend the electron source within the RF cavity of the electron injection system.