Compact D-Li Neutron Generator for High-Yield 225Ac Production
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Solution Overview
Problem
Current methods for producing Actinium-225 (225Ac) are cumbersome, require large and expensive accelerators or reactors, and do not efficiently meet the global demand, necessitating a compact and efficient production method.
Innovation Solution
A compact D−7Li neutron generator system comprising an ion source chamber, RF generator, converter, magnetic field generator, and target electrode, which generates high-energy neutrons to irradiate Radium-226, producing 225Ac via the 226Ra(n,2n)225Ra nuclear reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large accelerators or nuclear reactors are used to produce 225Ac, then production quantity and reliability are improved, but device complexity, cost, and operational difficulty increase significantly
Solution Approach 1:
The system segments the neutron production process into two independent stages: (1) a compact accelerator producing deuterium ions that strike a beryllium target to generate fast neutrons, and (2) these neutrons irradiating a 226Ra target to produce 225Ac. This segmentation allows each component to be smaller and less complex than a single large accelerator or reactor system, while maintaining high production efficiency
Solution Approach 2:
The patent introduces an intermediary substance (beryllium target) that converts the accelerator's deuterium ion beam into a neutron flux. This intermediary enables the use of a lower-energy, more compact accelerator instead of requiring a large high-energy accelerator or reactor, thereby reducing device complexity while maintaining neutron production capability
2Reliability
If conventional ion sources are used, then device simplicity is maintained, but back-streaming electrons cause operational issues and reduce reliability
Solution Approach 1:
The patent inverts the conventional ion source design by using a negative ion source instead of a positive ion source. In conventional sources, positive ions are produced and accelerated, causing electron back-streaming that damages components. By producing negative deuterium ions (D-) and accelerating them, the system eliminates back-streaming electrons while improving operational reliability, as the negative ions are more stable and do not cause the same operational issues
3Productivity
If high energy protons or photons are used for irradiation, then 225Ac production efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the energy parameter of the incident particles from high-energy protons or photons (requiring large accelerators) to lower-energy deuterium ions (10-20 MeV) that can be produced by compact accelerators. The deuterium ion beam strikes a beryllium target to produce neutrons with appropriate energy (2-10 MeV) for the 226Ra(n,2n)225Ac reaction, achieving high production efficiency with reduced power requirements and smaller device footprint
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 system enables reliable high-yield production of 225Ac with minimal back-streaming electrons, reducing operational issues and costs, suitable for preclinical and clinical applications.
Implementation Method 1
The RF generator may be configured to drive RF currents through said RF antenna to heat the plasma generated within the ion source chamber
Implementation Method 2
The magnetic field may be generated within the ion source chamber using one or more rows of magnets to form a multi-cusp magnetic field configuration for plasma confinement
Implementation Method 3
The source electrode may comprise an electrode having a negative bias voltage relative to the plasma to generate negative deuterium ion on the converter surface and subsequent acceleration across the plasma sheath
Implementation Method 4
In various embodiments, the source exit electrode may comprise an electrode having a positive bias voltage relative to the source chamber to eliminate the exit of positive deuterium ions and electrons generated within the source chamber to minimize the exposure of the target electrode to X-rays
Implementation Method 5
The D−7Li neutron generator may be configured to produce 225Ac from irradiation of at least one said 226Ra samples forming 225Ra/225Ac via the 226Ra(n,2n)225Ra nuclear reaction
Data Source
AI summary
The present disclosure provides a D−7Li neutron generator system and methods for producing a large amount of 225Ac. High flux 10 and 13 MeV neutrons generated by the (D−7Li) reaction are used to irradiate 226Ra forming 225Ra/225Ac via the 226Ra(n,2n)225Ra reaction. The generator consists of three main components: (1) a surface-production type negative ion source; (2) an extraction and acceleration column; and (3) a beam target Lithium electrode to irradiate 226Ra resulting in the formation of 225Ac. The methods enable the negative deuterium ion-base compact neutron generation system to generate reliably high yield of neutron flux in the absence of back-streaming electrons for producing 225Ac in large quantities but with a very small percentage of 227Ac (˜1%).