Revolution in imaging with neutrons: FRM II research group develops new processing method for image data
TECHNICAL UNIVERSITY OF MUNICHCorporate Communications Center
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Revolution in imaging with neutrons
FRM II research group develops new processing method for image data
An international research team at the Research Neutron Source Heinz Maier-Leibnitz (FRM II) of the Technical University of Munich (TUM) have developed a new imaging technology. In the future this technology could not only improve the resolution of neutron measurements by many times but could also reduce radiation exposure during x-ray imaging.
Modern cameras still rely on the same principle they used 200 years ago: Instead of a piece of film, today an image sensor is exposed for a certain period of time in order to record an image. However, the process also records the noise of the sensor. This constitutes a considerable source of interference especially with longer exposure times.
Together with colleagues from Switzerland, France, the Netherlands and the USA, Dr. Adrian Losko and his TUM colleagues at the Heinz Maier-Leibnitz Zentrum (MLZ) have now developed a new imaging method which measures individual photons on a time-resolved and spatially-resolved basis. This makes it possible to separate photons from noise, greatly reducing the interference.
"Our new detector lets us capture every individual photon and thus overcome many of the physical limitations of traditional cameras," says Dr. Adrian Losko, instrument scientist at the NECTAR neutron radiography facility of the Heinz Maier-Leibnitz Zentrum at the Technical University of Munich.
Measuring individual photons
Neutron radiography researchers typically use scintillators in their measurements to detect neutrons for example in the examination of fossilized dinosaur eggs. When the scintillator material absorbs a neutron, photons are generated which can then be measured.
Until now all of these cameras have collected light during the entire exposure time, resulting in a lack of definition, depending on the thickness of the scintillator. The research team's new concept on the other hand detects each individual photon generated by a neutron.
"The prerequisite was a new chip technology as well as hardware and software that support computing speeds which enable real-time analysis. This lets us compose an image neutron by neutron," explains Losko. Here neutron research offers an ideal test and application field.
Instead of longer exposure times: Measuring exactly what happens
Since the absorption of a neutron in the detector generates several photons, the new system can use coincidence measurement of several photons to determine individual neutrons. "This takes us away from the traditional model of exposure time and we measure only those events which have occurred."
Compared to all technologies previously available on the market, the new concept is a dramatic improvement since it enables three times better spatial resolution and reduces the amount of noise by more than seven times. "This greatly reduces the limitations resulting from the thickness of the scintillator, which means higher efficiency for high-resolution measurements," says Losko. And the afterglow of the scintillator, which creates what are referred to as ghost images, is eliminated as well.
"Many of the instruments at the research neutron source reactor can benefit from our new concept," observes Losko, citing as an example the instrument FaNGaS (Fast Neutron-induced Gamma-ray Spectrometry): "Since we know exactly when a neutron arrives, the time-span during which we measure the gamma particle can be reduced to a millionth of a second." This would reduce the background noise by a factor of one million, he adds.
Lower radioactive exposure and more details in x-rays
The new detector can also be applied in medical fields. When making an x-ray image of a broken bone for example, fine structures such as hairline fractures would be more easily detectable; at the same time, the patient's exposure to radiation would be minimized.
"Our method will definitely change detectors in the scientific world," says Losko. And perhaps similar principles will also make their way into application in everyday cameras for personal use. Images made in the dark would be greatly improved, and photographers could adjust exposure time and resolution after the exposure is made. Noise could be practically eliminated from cameras.
Adrian Losko, Yiyong Han, Burkhard Schillinger, Aureliano Tartaglione, Morgano, Markus M. Strobl, Jingming Long, Anton Tremsin, Michael Schulz
New Perspectives for Neutron Imaging through Advanced Event-Mode Data Acquisition
Sci Rep. 11, Article number: 21360 (2021) – DOI: 10.1038/s41598-021-00822-5
The research activities were supported by German Federal Ministry of Education and Research (BMBF). In addition to the scientists of the Research Neutron Source Heinz Maier-Leibnitz (FRM II) at the Technical University of Munich, researchers at the Paul Scherrer Institute PSI in Villigen, Switzerland, Amsterdam Scientific Instruments B.V. (Netherlands) and the Space Sciences Laboratory of the University of California, Berkeley (USA), were also involved in the project.
Dr. Adrian Losko
Technical University of Munich
Research Neutron Source Heinz Maier-Leibnitz (FRM II)
Lichtenbergstr. 1, 85748 Garching, Germany
Tel.: +49 89 289 14756 – e-mail: Adrian.Losko@frm2.tum.de
Instrument NECTAR: https://mlz-garching.de/medapp-nectar
The Heinz Maier-Leibnitz Zentrum (MLZ) is a leading center for cutting-edge research with neutrons and positrons. Operating as a user facility, the MLZ offers a unique suite of high-performance neutron scattering instruments. This cooperation involves the Technical University of Munich, the Forschungszentrum Jülich and the Helmholtz-Zentrum Hereon. The MLZ is funded by the German Federal Ministry of Education and Research, together with the Bavarian State Ministry of Science and the Arts and the partners of the cooperation. https://mlz-garching.de/englisch.html
The Technical University of Munich (TUM) is one of Europe’s leading research universities, with more than 600 professors, 48,000 students, and 11,000 academic and non-academic staff. Its focus areas are the engineering sciences, natural sciences, life sciences and medicine, combined with economic and social sciences. TUM acts as an entrepreneurial university that promotes talents and creates value for society. In that it profits from having strong partners in science and industry. It is represented worldwide with the TUM Asia campus in Singapore as well as offices in Beijing, Brussels, Mumbai, San Francisco, and São Paulo. Nobel Prize winners and inventors such as Rudolf Diesel, Carl von Linde, and Rudolf Mößbauer have done research at TUM. In 2006, 2012, and 2019 it won recognition as a German "Excellence University." In international rankings, TUM regularly places among the best universities in Germany. www.tum.de