Physicists have created a radionuclide for medical diagnostics in a particle accelerator

During the tests, scientists continuously irradiated a one-mm molybdenum target for 115 hours.

focused electron beam with a power of 30kW. This is exactly how long it takes to create an isotope. Physicists note that the biggest hurdle with such extreme exposure was keeping the target cool, which could evaporate in milliseconds without dissipating heat.

Surface temperature during the experimentrises from 200°C to 600°C, so it is not possible to use water for cooling. Instead, physicists used liquid sodium. Liquid metals have a high specific heat capacity and thermal conductivity, which makes them very efficient at removing heat.

The researchers chose as the refrigerantliquid sodium, since it is already used in nuclear power. The problem with this substance is that sodium reacts actively with air and water and can dissolve other metals, the researchers note. In addition, at room temperature, sodium becomes a solid state, so if individual systems fail, it cools and can clog heat pipes.

However, according to scientists, the resultsexperiments have shown that the use of liquid sodium as a heat sink under extreme conditions is justified. Scientists note that the power density in the target is billions of times greater than in the core of the Sun, and the wall of a nuclear reactor receives a similar exposure in 10 years. However, the target, cooled with liquid sodium, was able to survive five days of continuous irradiation.

Physicists plan to scale technology tocomplete production of radioisotopes. The target used in the experiment is a thousand times smaller than the one that the scientists plan to use in the industrial installation of the SMART project. The participants of the experiment hope that by 2028 there will be a plant for the production of radioisotopes for hospitals around the world.

Technetium-99m is an isomer of the isotope technetium-99.It is a metastable radionuclide that emits gamma radiation. Technetium-99m is formed after the beta decay of the nuclide molybdenum-99. This isomer is used as a radiochemical for medical diagnostics in tens of millions of procedures annually. Because of its short half-life (about six hours), the technetium isomer is typically obtained from molybdenum directly in a medical laboratory.

At present, most of the molybdenum-99produced from enriched uranium in nuclear reactors. Such production cannot fully satisfy demand, and a large amount of radioactive waste is produced as a result of the decay of enriched uranium.

Cover image: Jürgen Jeibmann, Center im. Helmholtz Dresden-Rossendorf

Read more:

Nuclear fusion no longer needs millions of degrees: how the new method works

Aircraft A380 completes first vegetable oil flight

Scientists Finally Understand How Soft Liquid Droplets Destroy Hard Surfaces