Physicists Gather in Estonia to Find New More Optimal Ways to Use the Power of Luminescence and Radiation


Efficiency in using luminescent detectors and ionizing radiation was also the main topic at the 9th International Conference on Luminescent Detectors and Transformers of Ionizing Radiation LUMDETR 2015* held in Tartu during the last week of September. The conference provided an overview of the latest achievements in basic and applied research in the field of luminescence, the storage and transformation of ionizing radiation in solids; the physics and chemistry of luminescent phosphors, dosimetric and scintillation materials as well as all related applications.

While radiation has been used in medicine, manufacturing and transport industries for decades, scientists are still trying to find the symbiosis between different scientific fields in order to figure out how to make radiation doses as small and precise as possible or put them to work as fast as possible.

“Airports and marine ports are getting bigger and busier. Right now the U.S. government has launched a new homeland security program, which means installing the new generation of luminescent detectors into the aforementioned terminals for security checks. The devices need to work as quickly as possible, as the number of containers that need to be checked is immense,” says Dr. Vitali Nagirnyi, senior researcher at the University of Tartu Institute of Physics, who was the Scientific Secretary of the conference. According to him, it’s a great challenge to find ways of building huge scanners that would be able to screen objects in only 20 seconds. “For that, we need knowledge on new materials sensitive enough to respond swiftly to the radiation needed in logistics,” Nagirnyi explains.

Sensitivity is the keyword here, as it’s one of the issues scientists are dealing with on a daily basis, both in Tartu as well as all over the world. While port checks are all about the timing, in medicine—the field where radiation is used in diagnostics and therapy—it’s about making radiation doses as small and precise as possible to alleviate harmful side effects.

“Radiation has a strong effect on the human organism; if the dose is too heavy, it might have a fatal influence. What is more, the used radiation needs to be absorbed at the right place when we’re dealing with radiotherapy, for example, if the exposed area is too large, radiation might also kill healthy cells of the living body instead of cancer cells only,” describes Aleksandr Lushchik, Professor of solid state physics at the University of Tartu and one of the organisers of the conference.

Thus, we need materials with a high sensitivity to radiation, so that the doses would be smaller and the time when people are exposed to radiation would diminish. One of the most fascinating conference presentations was about this very issue. “Up to now the movement of internal organs was not properly taken into account in radiotherapy. Yet, it’s a crucial issue because even if you’re exposed to radiation for a few minutes, your heart can move up to three millimetres, while in some cases even a 1 mm deviation can make a fatal difference. However, Professor Anatoly Rozenfeld from Australia showed an elegant method of adapting radiation technology to these movements,” Lushchik explains. Altogether, it is not uncommon for modern hospitals to have physicists next door to doctors for applying modern technology in medicine.

When Lushchik and Nagirnyi are asked about their own research, they emphasise analysing the counteractive effects between different materials and finding out what causes structural defects while working with radiation. Here, effectiveness becomes the keyword. “Radiation can damage materials, so we’re trying to find advanced compounds that are both sensitive and highly resistant to radiation. That’s what we’re competing in,” says Nagirnyi. In addition to defects, they’re also dealing with the issue of making modern light sources more efficient and long-lasting. “Even a minor improvement in material performance can lead to a huge reduction in spending due to the reduced price of light emitting materials and improved energy consumption, so most of the work we do here has a practical value,” Lushchik adds.

* 176 participants from 29 countries. The financial support came from Enterprise Estonia through its dedicated program for conferences and events that contributed to the successful organisation of the LUMDETR2015 conference.

This article was supported by the European Regional Development Fund through Estonian Research Council.

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