24 September 1998

Don't Break Wind - They Know You Did It

Scientists at the US Department of Energy, have developed two new devices that can detect nuclear detonations by analysing the atmosphere for traces of radioactive material. These systems, once activated, will be located around the globe and used to monitor the Comprehensive Nuclear-Test-Ban Treaty (CTBT) by detecting nuclear explosions.

"New technologies now enable us to detect and confirm nuclear explosions," said Under Secretary of Energy Ernest Moniz. The two new detonation identification devices offer greater sensitivity, full automation, near real-time reporting, and novel nuclear radiation detectoion.

ARSA, the Automated Radioxenon Sampler/Analyzer, and RASA, the Radionuclide Aerosol Sampler/Analyzer, were created to verify the Comprehensive Nuclear-Test-Ban-Treaty. An international monitoring system is being set up to use the latest technology to watch for evidence that nuclear weapons are being tested. ARSA and RASA will comprise a large part of the technology employed in an 80-station radionuclide network. "ARSA is the most valuable radionuclide detection method available to the Comprehensive Test Ban Treaty (CTBT)," said Ted Bowyer, Pacific Northwest principal investigator for ARSA. "These two systems allow us to capture a tiny part of the weapon. Radionuclides are a smoking gun. They are positive confirmation of recent nuclear fission."

ARSA analyzes air samples for radioactive xenon, or radioxenon, that seeps from underground nuclear explosions - the most common testing method today but the most difficult to detect. ARSA has a detection sensitivity 10 to 100 times greater than other systems being used. In addition, it is the only completely automated radioactive xenon monitor. ARSA collects air samples, then processes them to trap the radioactive xenon on cold charcoal. The system purifies the radioactive xenon, then transfers it to a nuclear counting system. The different isotopes of xenon are automatically measured, then the results are automatically passed to a data center by communication link. ARSA can be accessed by modem and programmed remotely. RASA detects fission products from atmospheric nuclear explosions. This basic technique has been available for 30 years, but Pacific Northwest researchers have created the most sensitive automated system ever - more than 100 times as sensitive as the best previous technology. RASA filters a huge volume of air each day to check for evidence of fission products from a nuclear explosion that attach to dust particles. The automated system draws air through a series of filters, which remove practically all of the atmospheric particles. The filters are sealed, bar coded, then passed to a radiation detection system. Radiation from weapons debris is then registered and translated to prove a violation of the treaty.