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Ionising radiation sign

Optical systems for safe and reliable measurement of contamination incidents

The project

Radiological emergencies involving an accidental or deliberate dispersion of alpha emitting radionuclides in the environment can cause significant damage to humans. Alpha particles represent the biggest risk to soft biological tissues compared to all nuclear decay products due to their high energy, large mass and high linear energy transfer.

Previously, detection systems to measure large-scale contamination of these radionuclides were not available. In the case of an emergency, the only option was to evacuate the population form the affected areas and then run diagnostics by hand, exposing emergency teams to considerable risk.

Even then, the results of emergency field applications were notoriously ambiguous, time consuming and tedious due to the centimetre (cm) range of the alpha particles in air. The main difficulty with detecting the particles is that they travel a distance of around just 1 cm in air, meaning that remote sensing is problematic. New remote detection techniques which overcome the shortcomings of traditional detectors were needed.

Completed EMPIR project Remote and real-time optical detection of alpha-emitting radionuclides in the environment (19ENV02, RemoteALPHA) developed novel instrumentation and methods and a sustainable metrological infrastructure for outdoor-detection systems, which can detect remotely alpha-emitting radionuclides in the environment. This includes two lens-based radioluminescence detection systems, a novel calibration methodology based on radiance standards, environmental standards, and an unmanned aerial monitoring system.

Project outcomes

The project consortium developed, for the first time, practical remote methods to measure alpha radiation in the environment.

A remote detection system based on the ‘luminescence’ caused by alpha particles that hit substances such as nitrogen in the atmosphere was developed. Alpha particles in air have a very short range because they are large, highly charged, and interact strongly with atoms in their path. Alpha particles are emitted by radionuclides such as Po-210. In the event of an accident involving Po-210, Po-210 would be dispersed and deposited in the environment, and the wind can disperse it further. Po-210 then emits alpha particles. With conventional detection techniques (scintillation detectors, gas-based detectors or silicon-based detectors), without precise information about where the Po-210 is located (so that you can place a detector very close to the surface), it is very difficult to find it. With telescopes developed in the project, it is possible to place the detector nearby (without knowing where Po-210 is deposited) and scan the space around it. In places where Po-210 is deposited, RemoteALPHA detectors will detect UV-A or UV-C radiation produced by the ionisation of the air by alpha particles.

The selection of the optics and atmospheric effects that amplify the luminescence, along with the advancements in UV radioluminescence detection was key for the success of this project and the difference it will make for alpha particle monitoring. Alpha particles can cause radioluminescence in certain gases, but not all gases. For example, if the room where the alpha contamination is located is flushed with nitrogen, the radioluminescence is increased by a factor of around six. The consortium was able to get images of alpha contamination of leaves, concrete and other solids even at low alpha activity levels. The technology behind this work had been previously developed and proven, but the project consortium designed the novel optical set-up that enabled the technology to be taken into the environment. 

Two radioluminescence sources for calibration and two detector systems to detect this luminescence were developed. One detector system is tripod based and the other was placed on an unmanned drone, as described in the paper Mapping of Alpha-Emitting Radionuclides in the Environment Using an Unmanned Aircraft System

The Hungarian Armed Forces have run training courses based upon the technology in this project. Military experts gave presentations introducing participants to the characteristics of nuclear weapons and the dangers of radiological weapons. This was followed by a presentation on the possibilities of detecting alpha radiation with drones, as developed in the RemoteAlpha project.

Summary of the ‘Measurement of radiological and CBRN materials’ practice and learning day

Details of ‘Military methods and possibilities of radiation detection of radioactive materials’ learning day

The work of this project will lead to real-time collection of traceable radiological data and faster, more reliable information for the decision-making authorities.

Project coordinator Faton Krasniqi from PTB said

‘The RemoteALPHA project has developed innovative optical systems for the remote detection of alpha-emitting radionuclides, addressing critical challenges in nuclear safety, emergency response, and environmental monitoring. The project’s breakthroughs—such as portable UV-radioluminescence detection systems (using fused silica and PMMA Fresnel lenses), UAV-integrated mapping systems, and traceable calibration methodologies—enable rapid, accurate, and safer identification of alpha contamination without direct human exposure. By advancing radioluminescence technology and demonstrating feasibility in real-world scenarios (e.g., airborne mapping with drones), the project bridges a key gap in radiation detection, offering tools that enhance preparedness for nuclear incidents, decommissioning, and safeguards.’

This EMPIR project is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States.

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