2008 R&D 100 Winner
Neutron detectors are important in many applications, ranging from fundamental physics to personal protective equipment for first responders. Conventional neutron detectors are based on high-voltage proportional counters that detect the high-voltage electrical discharges created when neutrons are absorbed by atoms in a gas cell. These detectors are susceptible to false-positive electrical discharges and are difficult to manufacture. Overcoming these flaws is the Lyman Alpha Neutron Detector (LAND), designed by researchers at the National Institute of Standards and Technology (NIST), Gaithersburg, Md., and the Univ. of Maryland, College Park. LAND is a high sensitivity, wide dynamic range detector of slow neutrons that uses a novel extreme ultraviolet detection mechanism: it measures Lyman alpha radiation in the far ultraviolet region of the spectrum when neutrons are absorbed by a helium isotope.
A LAND instrument can detect individual neutrons, which was not possible with proportional counters, and LAND is less susceptible to spurious signals triggered by gamma rays. The device is mechanically robust and requires no specialized fabrication techniques or ultra-high purity gases.