New scintillating composite leads to versatile and inexpensive neutron sensor

Los Alamos National Laboratory has announced the development of a new type of neutron sensor that works across a wide range of conditions, including in the presence of strong gamma radiation.

The technology is called the Integrated Composite Optical Neutron Sensor (ICONS).

"Measuring neutrons accurately is critical for a variety of applications, including energy research, national security, scientific experiments, medicine, and nuclear safeguards," said Markus Hehlen, a scientist at LANL and ICONS team lead. "But getting accurate neutron measurements is surprisingly hard."

Helium-3 gas-filled neutron proportional detectors are widely used, but a shortage of the gas in recent decades has made it expensive and difficult to obtain. Many newly developed sensors, such as ICONS, have focused on lithium-6-based designs to avoid that problem.

Using a scintillating composite that is new to neutron detector design, consisting of Li-6 glass scintillator particles dispersed in an organic matrix, Hehlen said ICONS has been demonstrated to meet or even surpass traditional He-3 based detectors.

"The composite scintillator architecture of ICONS enables exquisite neutron/gamma discrimination via a simple pulse-integral method, thereby significantly reducing the complexity of pulse-shape discrimination approaches that have to be used for other Li-6-based bulk scintillator technologies," Hehlen told Nuclear News.

Using a dual readout of the photomultipliers used to detect the scintillation light, ICONS achieves a wide and linear measurement range. According to LANL, it can detect anything from individual background neutrons up to extremely intense neutron fluxes without losing accuracy.

A 2025 article published in Communications Physics stated that "the compactness and modularity of the present Li-6 glass particle detection system are essential features. They are particularly valuable for nuclear security and emergency applications, where portability is crucial."

A more complex nuclear age: Similar work is ongoing in the Defense Threat Reduction Agency's Research and Development Directorate, which is tasked with enabling the deterrence of attacks against the United States. Seeking to meet the need for handheld radiation detectors that can be used in the field, DTRA researches radiation-detection materials and has also explored scintillator-based designs. The agency developed advanced inorganic scintillating crystals with both gamma ray and neutron discrimination capabilities, which could potentially replace two separate devices in a service member's pack.