Rotating Converter Target for High-Power Bremsstrahlung
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Solution Overview
Problem
Current technologies lack the capability for industrial-scale, cost-efficient production of rare but highly demanded diagnostic and therapeutic radionuclides, such as 225Ac and 99Mo, using photonuclear irradiation due to the limitations in high-power electron accelerators and converter targets that can withstand high-intensity electron beams.
Innovation Solution
A facility for radionuclide production based on photonuclear irradiation, comprising an electron accelerator, a converter target assembly with rotating disks to distribute the electron beam energy and cool the target, and production targets irradiated by Bremsstrahlung photons to produce radionuclides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high-power electron beam is directed onto a converter target to produce Bremsstrahlung photons for photonuclear reactions, then the production yield of radionuclides is improved, but the heat load on the converter target increases to a level that cannot be withstood by conventional targets
Solution Approach 1:
The converter target is divided into multiple converter disks arranged in a stack, where each disk receives a portion of the electron beam energy. This segmentation distributes the heat load across multiple components rather than concentrating it on a single target, enabling the system to handle high-power electron beams while maintaining manageable temperature levels on each individual disk.
Solution Approach 2:
The converter disks are designed to rotate during operation, which dynamically distributes the electron beam impact across different areas of each disk over time. This rotational movement prevents localized overheating by continuously changing the impact location, allowing the target to withstand high beam powers that would otherwise cause thermal damage to stationary targets.
2Use of energy by moving object
If the electron beam is focused to a small spot on the converter target, then the Bremsstrahlung photon flux is improved, but the focal spot concentration causes excessive heat buildup that damages the target
Solution Approach 1:
The target system is segmented into multiple disks, so that the focused electron beam impacts only one disk at a time while others remain cool. This segmentation allows the system to maintain a focused beam for high photon flux while distributing the thermal stress across multiple segments, preserving target integrity.
Solution Approach 2:
The rotation of the converter disks creates a dynamic distribution of the focused beam impact across the entire disk surface over time. This dynamic approach maintains the instantaneous focus needed for high photon flux while preventing permanent damage by continuously moving the impact location, allowing the target to withstand conditions that would damage static targets.
3Productivity
If conventional stationary converter targets are used, then the device complexity is kept simple, but the targets cannot withstand high-intensity electron beams for industrial-scale production
Solution Approach 1:
The introduction of rotating converter disks adds dynamic capability to the target system, enabling it to withstand high-intensity electron beams required for industrial-scale production. The rotation mechanism distributes heat load effectively, allowing the system to operate at higher powers that enable industrial production levels.
Solution Approach 2:
The converter target is segmented into multiple rotatable disks, which distributes the thermal and mechanical stress across multiple components. This segmentation allows the system to handle industrial-scale beam powers while maintaining manageable complexity through modular design, where each disk can be independently cooled and replaced if needed.
4Power
If a single thick converter target is used, then the Bremsstrahlung production is efficient, but the heat removal becomes insufficient and the target overheats
Solution Approach 1:
The thick converter target is segmented into multiple thinner disks stacked together. Each disk maintains sufficient thickness for efficient Bremsstrahlung production while the stacked arrangement creates interspersed cooling channels. This segmentation allows heat to be removed more effectively through the cooling medium flowing between disks, preventing overheating while maintaining production efficiency.
Solution Approach 2:
The rotation of the converter disks dynamically exposes different surfaces to the electron beam and cooling medium, enhancing heat transfer efficiency. This dynamic configuration allows the system to maintain high power conversion efficiency while improving heat removal capability through continuous movement and exposure of fresh surfaces to the cooling flow.
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 facility enables high-yield production of radionuclides with high reliability, safety, and minimal raw material consumption, overcoming previous limitations in equipment design and operation.
Implementation Method 1
a converter target assembly with a converter target that converts the electron beam to Bremsstrahlung photons
Implementation Method 2
comprising cooling medium ports, these ports being part of a cooling circuit for establishing a cooling flow through the cavity, thereby cooling the converter target and the entry window
Implementation Method 3
establishing a cooling flow through the cavity, thereby cooling the converter target and the entry window
Implementation Method 4
the respective converter disk is designed to rotate during operation of the facility, thereby, in the course of time, spreading or distributing the focal spot of the electron beam over an annular area of the converter disk
Data Source
AI summary
A facility for the production of radionuclides based photonuclear irradiation, comprising: an electron accelerator (1), producing an electron beam (2); a converter target assembly (21) with a converter target (20) that converts the electron beam (2) to Bremsstrahlung photons (15); a production target (17), irradiated by the Bremsstrahlung photons (15) and thereby producing said radionuclides.