When neutrons interact with matter, they create a cascade of nuclear responses—prompt gamma emissions, delayed neutron signatures, and backscattered particles—that reveal material composition with extraordinary precision. These neutron interrogation techniques provide non-destructive, penetrating analysis that can identify elements from hydrogen to uranium, detect hidden nuclear materials, and map subsurface formations through depths of steel or rock.

This family of methods includes neutron activation analysis (NAA), prompt gamma neutron activation (PGNAA), neutron backscatter, and active neutron interrogation for special nuclear materials. Each technique exploits different aspects of neutron-nucleus interactions: thermal neutron capture produces characteristic gamma rays, fast neutrons induce fission in fissile materials, and hydrogen-rich materials preferentially scatter neutrons back toward detectors. Together, these approaches solve critical industrial and security challenges that other analytical methods cannot address.

Modern industries increasingly demand rapid, accurate material analysis in challenging environments—from screening cargo containers at ports to characterizing oil reservoirs thousands of feet underground. Neutron interrogation provides answers when other techniques fail, penetrating through barriers, analyzing bulk volumes rather than surfaces, and detecting light elements that X-rays miss entirely. The combination of high sensitivity, multi-element capability, and standoff detection has established neutron methods as essential tools for security, resource extraction, and quality control.

Neutron interrogation serves critical roles across diverse sectors. Examples include:

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Expanding Neutron Interrogation with Fusion Sources

The transformative power of neutron interrogation has been constrained by source availability. Historically, these techniques required research reactors, radioisotope sources with security concerns, or large accelerator facilities, limiting routine industrial application despite clear technical advantages. Smaller radioisotope-based neutron sources are another option but pose a regulatory burden as they require actinides like Californium-252 and Americium-241.

Furthermore, Californium-252 sources decay rapidly and require frequent replacement, and Americium-241 Beryllium (AmBe) sources offer limited neutron output and pose a regulatory burden.

In recent decades, this landscape has changed with fusion neutron sources. Compact fusion devices can now generate the neutron fluxes required for industrial interrogation without the complexity or regulatory burden of previous solutions. These systems enable:

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• On-Demand Operation: Fusion sources produce neutrons only when powered on, eliminating radiation hazards during maintenance and transport
• Tunable Output: Adjustable neutron energy and intensity optimized for specific applications—from thermal neutrons for activation analysis to 14 MeV neutrons for cargo screening
• Continuous Availability: No decay or refueling concerns enable 24/7 operation at industrial sites
• Enhanced Safety: No actinides, limited if any radioactive waste, and instant shutdown capability

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As fusion technology continues to mature, neutron interrogation is transitioning from a specialized capability to an accessible industrial tool. This broader accessibility brings advanced material analysis to ports, mines, and factories worldwide. From identifying concealed threats to optimizing resource extraction, fusion-driven neutron sources are unlocking applications that have waited decades for practical implementation.

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