Vilnius University physicists patent pea-sized triplex radiation sensor
Physicists at Vilnius University (VU) have developed a radiation sensor capable of detecting a wide range of doses, identifying the type of radiation present, and pinpointing the direction and distance of the source in real time. The device, smaller than a pea, was created by researchers at the Institute of Photonics and Nanotechnology's Photoelectric Phenomena Research Group and was patented in 2025.
The sensor is described as a triplex architecture, combining three distinct material layers: a scintillator, an organic electron spin resonance (ESR) sensor, and a semiconductor photosensor. Each layer interacts differently with incoming radiation, allowing the combined readout to discriminate between radiation types and reconstruct dose and spectral information. Laser sources excite both the scintillator and the semiconductor photosensor, with signals collected via optical fibre and measured by a spectrophotometer and a microwave response system respectively. The ESR sensor is read out separately using an ESR spectrometer.
"The sensor consists of three layers: a scintillator, an organic ESR sensor, and a semiconductor photosensor, whose signals are read sequentially by a dedicated device," said Prof. Tomas Ceponis, who leads the programme at VU's Faculty of Physics. "A combined analysis of these signals makes it possible to determine the radiation dose and the radiation spectrum."
The device is designed to operate across a very broad dose range, from trace-level exposures up to megagray intensities typical of industrial irradiation facilities or severe nuclear accidents. The team says it can also function remotely, with drone-mounted deployment cited as a practical route for surveying contaminated or hazardous sites without putting personnel at risk.
Lineage and validation
The triplex sensor builds on earlier dosimetry instrumentation developed at VU under Prof. Eugenijus Gaubas, a predecessor device that has been installed and is in operational use at CERN, the European Organisation for Nuclear Research in Geneva. That connection to a high-energy physics environment provides meaningful validation for the underlying measurement principles, even if the new sensor targets a broader set of deployment scenarios.
Prof. Gaubas, Prof. Ceponis, Dr Laimonas Deveikis, Dr Jevgenij Pavlov and Assoc. Prof. Vytautas Rumbauskas received the VU Rector's Award for significant scientific achievement in the category of best applied research for the invention.
Market and competitive context
Radiation detection is a well-established instrumentation market, served by a range of established suppliers producing Geiger-Muller tubes, scintillation detectors, and solid-state silicon detectors for health physics, nuclear power and security screening. The VU device's claimed differentiator is its ability to perform simultaneous dose measurement, radiation-type discrimination and source localisation from a single compact unit, capabilities that typically require separate instruments in conventional deployments.
Regulators and operators at nuclear facilities increasingly require real-time, remotely deployable sensing capability, a need brought into sharp focus by the Fukushima Daiichi accident in 2011 and reinforced by subsequent IAEA guidance on emergency preparedness. The civil protection and nuclear power plant monitoring applications cited by the VU team place the sensor squarely in a space where several university spinouts and defence-adjacent technology companies are active. Whether VU intends to commercialise the technology directly or license it to an industrial partner has not been disclosed. The next milestones to watch are pilot deployments in operational environments and any indication of commercial agreements with nuclear industry or civil protection agencies.