Nuclear weapons detectionSpecialized gas detection helps prevent nuclear weapons proliferation
Researchers aim to design a system capable of sensing, from among the loud signals of a lot of gases, the weak signals from specific gases which are signs of nuclear weapons proliferation. The researchers believe their gas correlation technique will prove ideal for a simple, inexpensive sensor to monitor those few illusive gases. This could change how the nation thinks about monitoring the spread of nuclear weapons. Instead of single-point measurements taken with expensive sensors deployed after someone suspects a problem, 24/7 continuous monitoring could find leaks early.
Trying to sniff out traces of hard-to-detect gases can be like trying to hear a whisper at the other end of a very large, very crowded, very noisy room.
Sandia National Laboratories’ Project Neptune aims to design a system capable of sensing, from among the loud signals of a lot of gases, the weak signals from specific gases which are signs of nuclear weapons proliferation. The researchers believe their gas correlation technique will prove ideal for a simple, inexpensive sensor to monitor those few illusive gases.
“The hope is to detect gas early so there’s evidence before a nation gets too far along in a proliferation program,” said Jeff Mercier, a manager in Sandia’s Mission Science and Analysis Department and Neptune’s principal investigator.
With about one photon out of every million coming from the signal the Neptune sensor is seeking, “it’s a very, very hard problem,” he said.
The goal is an imaging technique that could be used in airborne- or space-based systems, said Steve Vigil, project team lead. The three-year project has wrapped up but was continuing to analyze data from a December test of the prototype Neptune gas correlation imaging system.
Field test gathers data
A Sandia Lab release reports that the field test at the Nevada National Security Site piggybacked on a larger, separate test. The test was calibrated, “so we knew where they were releasing things, what they were releasing and when they were releasing it,” Vigil said.
While the sensor and software worked well, the test conditions were different from those the instrument was designed for. The team planned to capture an image of something about the size of a meter from half a kilometer away, but ended up trying to image something that was only about a centimeter in size, Vigil said.
Neptune was funded under the Nuclear Fuel Cycle Remote Sensing portfolio of the National Nuclear Security Administration’s Office of Proliferation Detection. A small Albuquerque business, CIC Photonics, which designs and produces analytical and industrial instrumentation and sampling systems, worked with Sandia to design and build Neptune’s gas cells and did calibrated measurements of the cells.
The gas cells are the key. Sandia’s instrument contains two, each weighing around twenty pounds, in a stainless steel box about 3 feet square by 16 inches high. A beam splitter separates sunlight coming in the sensor’s window into two paths — one going to a cell filled with the gas
