How iThemba LABS is Harnessing Radioactive Beams for Science and Society
Imagine holding a key that can unlock secrets of the universe, from the fiery hearts of stars to new cancer treatments. This key isn't a physical object, but an extraordinary scientific tool: a radioactive ion beam.
At iThemba Laboratories for Accelerator-Based Sciences (LABS) in South Africa, scientists are mastering the art of creating these rare, unstable atomic particles to push the boundaries of human knowledge. These exotic nuclei don't exist naturally on Earth but hold tremendous potential across fields ranging from nuclear physics to medical therapy.
The growing availability of Radioactive Ion Beams (RIBs) worldwide has opened up new scenarios and challenges in nuclear physics. These special beams allow scientists to explore isotopes that have a proton-to-neutron ratio very different from stable ones, measure cross sections of important reactions for stellar nucleosynthesis occurring in explosive astrophysical environments, and even synthesize superheavy elements 1 .
Studying stellar processes and element formation
Developing new diagnostic and therapeutic isotopes
Radioactive ion beams (RIBs) are streams of charged atoms that have unstable nuclei. Unlike stable atoms that remain unchanged indefinitely, these radioactive isotopes decay over time, emitting radiation as they transform into more stable forms.
Creating them requires remarkable scientific ingenuity. At facilities like iThemba LABS, scientists start with a Penning ion source – a device that can produce world-record bright ion beams but traditionally suffers from limited lifetime 3 .
By recreating the nuclear reactions that power stars, scientists can solve long-standing mysteries about how elements form in the universe. The rapid proton-capture and alpha processes occurring in explosive environments like novae, X-ray bursters, and type Ia supernovae can be investigated using RIBs 1 .
Radioactive isotopes are crucial for both diagnosing and treating diseases. iThemba LABS utilizes its accelerator technology for medical isotope production, contributing to healthcare advancements while maintaining fundamental nuclear physics research programs 3 .
By studying how these exotic particles interact with matter, researchers can develop new materials with unique properties and gain insights into fundamental atomic structures.
A recent collaboration between iThemba LABS and the ISIS Neutron and Muon Source in the United Kingdom addressed one of the most persistent challenges in the field: the limited lifetime of Penning ion sources. These sources, while capable of producing exceptionally bright ion beams, would often degrade unexpectedly, disrupting important research and medical isotope production 3 .
The fundamental problem was that scientists couldn't observe what was happening inside the ion source during operation. The plasma conditions and accumulating impurities that ultimately led to failure were like a black box.
South African research facility
Radioactive ion beam productionUnited Kingdom research facility
Ion source development expertiseVisiting researcher (July 2025)
Technology transfer specialistThe optical diagnostics provided unprecedented insight into the inner workings of the Penning ion source. As Dr. Olli Tarvainen, an ISIS scientist leading the project, explained: "Measuring the light emitted by the plasma of an ion source with high sensitivity and time-resolution reveals how plasma conditions and impurities affect the beam production, and the longevity of the ion sources" 3 .
| Parameter | Traditional Operation | With Optical Diagnostics | Improvement Significance |
|---|---|---|---|
| Lifetime Predictability | Unpredictable failures | Real-time monitoring enables proactive maintenance | Reduces research downtime |
| Beam Stability | Gradual degradation | Stable performance through condition monitoring | More reliable experiments |
| Impurity Detection | Post-failure analysis | Real-time identification | Prevents catastrophic failure |
| Operational Efficiency | Scheduled replacement | Condition-based maintenance | Optimizes resource use |
This breakthrough enables accelerator operators to monitor ion source health in real-time and avoid conditions that compromise long-term performance. The benefits extend beyond either facility alone – by collaborating across continents, these research centers are advancing the global capability in accelerator science.
Creating and studying radioactive ion beams requires a sophisticated array of specialized equipment. At facilities like iThemba LABS, these tools work in concert to produce, manipulate, and detect the exotic nuclei that power cutting-edge research.
| Equipment/Technology | Function | Specific Application at iThemba LABS |
|---|---|---|
| Penning Ion Source | Produces intense ion beams | Generates primary beams for RIB production and medical isotopes 3 |
| Separated Sector Cyclotron | Accelerates particles to high energies | K=200 SSC accelerates protons to 200 MeV 6 |
| Fast Neutron Beam Facility | Produces quasi-monoenergetic neutron beams | Neutron beams from 30-200 MeV via (p,n) reactions using lithium and beryllium targets 6 |
| Optical Diagnostic Systems | Monitors plasma conditions in ion sources | Measures light emission from plasma to optimize performance and longevity 3 |
| Radioactive Ion Beam Tracking | Follows path and properties of RIBs | Event-by-event tracking to account for poor emittance of in-flight produced RIBs 1 |
The technological capabilities at iThemba LABS are particularly impressive. The laboratory's largest accelerator, a K=200 separated sector cyclotron (SSC) powered by two solid-pole injector cyclotrons, can accelerate protons to energies of up to 200 MeV and heavier particles to much higher energies 6 .
The facility's fast neutron beam capability is especially noteworthy. As researcher Zina Ndabeni described, "Over the years, the iThemba LABS fast neutron beam facility has been developed to a unique status with respect to the production of nearly monoenergetic ns-pulsed neutron beams ranging between 30 MeV and 200 MeV" 6 .
| Accelerator System | Key Capabilities | Research and Application Areas |
|---|---|---|
| K=200 Separated Sector Cyclotron | Accelerates protons to 200 MeV; heavier particles to higher energies | Fundamental nuclear physics, medical isotope production 6 |
| Solid-Pole Injector Cyclotrons | Feed particles into the main SSC | Initial acceleration stage 6 |
| Fast Neutron Beam Facility | Quasi-monoenergetic neutron beams (30-200 MeV) | Nuclear data measurements, radiation studies, international comparisons 6 |
| Ion Source Development Rig | Testing and optimization of ion sources | Improving beam quality and source longevity 3 |
iThemba LABS is currently undertaking significant upgrades to enhance its research capabilities. The fast neutron beam facility is being upgraded with the goal of achieving ISO-accreditation as a fast neutron beam reference facility.
This project, realized through collaboration between iThemba LABS, the University of Cape Town, and international partners including institutions from France, the UK, and Germany, will position the facility as a world-class reference site 6 .
Once the upgrade is complete, the facility will provide traceable measurements for medium and high-energy neutrons, addressing an important need in radiation science. The ISO-accreditation status will also enable the facility to participate in international key-comparison studies in neutron metrology 6 .
The research on ion sources directly impacts medical isotope production, potentially leading to more reliable supplies for diagnostic imaging and cancer treatment.
The improved beam quality and reliability enables more sensitive experiments exploring the fundamental forces and structures that govern our universe.
As demonstrated by the collaboration between iThemba LABS and ISIS, such projects represent a global scientific effort that transcends national boundaries 3 .
The facility serves as a training ground for scientists and engineers who will continue to push the boundaries of accelerator technology.
The upgraded facility is designed to accommodate irradiations of a phantom of up to 30 x 30 cm² beam size, expanding its practical applications 6 .
The work at iThemba LABS represents a remarkable convergence of fundamental research and practical application. By developing innovative solutions to long-standing challenges like ion source lifetime, scientists are not only advancing our understanding of the atomic nucleus but also ensuring that these extraordinary tools remain available for the next generation of discoveries.
As the facility continues to upgrade its capabilities and strengthen international partnerships, it stands as a testament to both South Africa's scientific ambitions and the global nature of modern research. The radioactive ion beams produced there may be invisible to the naked eye, but the light they shed on the mysteries of the universe – and the benefits they bring to society – could not be more brilliant.
This article was based on scientific research and announcements from iThemba LABS, the ISIS Neutron and Muon Source, and the International Atomic Energy Agency.