Korean-Style Medium-Ion Accelerator, What Is It Used For? [Reading Science]

IBS-built 'Raon' achieves first beam extraction in low-speed section ahead of full operation in March next year
Ultra-large observatory exploring atoms, neutrons, protons in the ultra-microscopic world
Peering into the femtometer scale, one-millionth of a nanometer
Used for exploring the secrets of the early universe, origins of life, and new drug development

[Asia Economy Reporter Kim Bong-su] "Recreating the primordial universe three minutes after the Big Bang."

On the 7th, the Korea-based Rare Isotope Accelerator (RAON), being developed by the Institute for Basic Science (IBS), successfully extracted its first beam ahead of its full-scale test operation scheduled for March next year. An accelerator is a tool that explores the ultra-microscopic world of atoms, beyond human cognitive ability, and the secrets of the birth of the early universe. It also has various practical applications such as new drug development, seed improvement, and semiconductor development using rare isotopes.

Peering into the Atomic World

Simply put, an accelerator is a device that ionizes particles, the smallest basic units of matter, atoms, and then makes them move rapidly. Atoms of all natural substances consist of nuclei and electrons and are stable in a neutral state under natural conditions. A hydrogen atom has one nucleus with an electron orbiting outside, and normally it is not accelerated. By artificially removing the electron, it becomes positively charged and turns into a hydrogen ion. This ionization is handled by the ion source device, an essential component of the accelerator. It forms a magnetic field to trap atoms and shoots an electron beam toward the target material. When this happens, the target material loses electrons and becomes ionized, and by applying a strong high-frequency electric field, particles begin to move at high speeds. This is the basic principle of an accelerator. To achieve this, the inside of the accelerator tube must maintain an ultra-low temperature (-273℃) and superconducting state where electrons can move without resistance. The internal surfaces must be processed and welded with extreme precision to minimize resistance, and assembly must be done in a clean room like in semiconductor manufacturing to eliminate contaminants.

Jung Young-se, Head of System Integration at IBS’s Heavy Ion Accelerator Project Group, explained, "The core technology of the accelerator is applying a high-frequency electric field that switches polarity about 81.25 million times per second to accelerate ions," adding, "Just as like poles of magnets repel each other, ions maintain the same charge state to increase acceleration."

RAON is a 'heavy ion accelerator' that accelerates relatively heavy atoms such as uranium. The project, with a total budget of 1.5 trillion KRW, has been under development since 2011. Currently, 54 accelerator tubes for the low-speed section, capable of accelerating particles up to about 30,000 km/s, are completed. On the 3rd, five of these tubes were test-operated, successfully extracting a beam. Core facilities such as superconducting accelerator tubes, superconducting cooling systems (maintained at -271℃), and high-frequency power supplies (high energy 325 MHz) were confirmed to be operating normally to accelerate particles. The institute aims to build 46 more accelerator tubes for the high-speed section to accelerate particles up to 50% of the speed of light (about 300,000 km/s). To this end, 12.6 billion KRW will be invested from this year through 2025 for preliminary R&D, after which construction of the high-speed section will proceed based on the results. Jung said, "There is no significant technical difference between the low-speed and high-speed sections, but since the speed is faster, larger, sturdier, and more precise accelerator tubes must be built and connected," adding, "Maintaining ultra-low temperature and superconducting states for a long time, as well as improving surface treatment, welding, and post-processing technologies, are key." He also noted, "It’s not so much a technical difficulty as a manpower shortage that has forced us to focus only on the low-speed section until now," and personally expects no major problems in constructing the high-speed section.

Unveiling the Mysteries of the Primordial Universe and Creating New Materials

What is a heavy ion accelerator used for? While conventional microscopes can only observe down to the nanometer scale (one-billionth of a meter, nm), a heavy ion accelerator is a kind of gigantic ultra-precision observation device that can explore the world of atoms, neutrons, and protons at the femtometer scale (one-millionth of a nanometer, fm). By accelerating ions and then colliding, splitting, and filtering them, various atomic nuclei can be created and their changes and interactions under different environments can be studied. For example, humans are made up of atoms whose nuclei consist of protons and neutrons, which form molecules, and molecules form proteins. Understanding the properties of atoms, neutrons, and protons, and even creating new ones, can bring significant advances in the origins of life and disease treatment.

The secrets of the early universe are also studied. The institute accelerates ionized particles such as uranium to speeds of 150,000 km/s and collides them with target materials, simulating conditions similar to three minutes after the Big Bang. Scientists currently estimate that protons and neutrons were formed within three minutes after the Big Bang, followed by nuclear fusion producing heavier atomic nuclei such as helium and lithium. This is the 'stellar nucleosynthesis process' that created the elements composing the universe. However, the formation process of heavy elements like iron (Fe) remains unconfirmed. The institute plans to install a 'KoBRA' recoil spectrometer at RAON to artificially recreate the environment three minutes after the Big Bang and study how nuclear reactions occur.

Discovering rare isotopes is another important goal. When ionized particles collide with specific materials, temperature rises and atomic fragments are produced, among which rare isotopes exist. For example, in 2016, the research team led by Morita Kosuke at Japan’s RIKEN used a heavy ion accelerator to discover a new element (atomic number 113), causing a worldwide sensation. Research on rare isotopes can be applied to creating new plant seeds, developing new materials and drugs, cancer treatment, and nuclear waste disposal technologies. RAON is designed to be the world’s first to simultaneously use an 'Online Isotope Separator (ISOL)' and a 'Flight Fragment Separator (IF)' to produce various rare isotopes with very short lifespans, raising high expectations. Additionally, a 'Large Acceptance Multi-Purpose Spectrometer (LAMPS)' will be constructed to study the properties of neutron stars. It will also be used in new material and semiconductor development. Using rare isotopes, new materials with novel properties can be developed. Radiation stability evaluation for semiconductors will be conducted at RAON instead of overseas accelerators, and new radiation therapy methods for cancer treatment will also be researched.