Thousands of centrifuges are needed and the engineering is tricky, but the process is more easily hidden, with reasonable electrical requirements and no heat or gas that can be detected by sensors.

ECONOMIST: Asia.view

This will generate two flashes of light - one in the liquid argon and another in the gas - which will be detected by the receptors.

BBC: Dark Matter: Experiment to shed light on dark particles

Once again, the way the particles knock electrons off the stuff they are travelling through (this time the gas) provides a useful signal (detected by the wires).

ECONOMIST: How to build a B-factory

On Monday Seoul announced that the Korea Institute of Nuclear Safety had detected unusually high levels of xenon gas near the North Korea border on May 14.

FORBES: Magazine Article

Xenon-133 is a radioactive noble gas produced during nuclear fission that poses no concern at the detected level.

FORBES: EPA Sounds an 'All-Clear' (so far) for Western U.S.

The light from the planet was detected in infrared form by the Spitzer Space Telescope, which also detected the first light from another exoplanet, the gas giant HD 209458 b.

FORBES: NASA Detects The Light Of A 'Super-Earth'

Last month, American officials said sensors on North Korea's borders had detected elevated levels of krypton-85 (a gas emitted when plutonium is extracted from spent fuel-rods) which did not seem to be coming from Yongbyon.

ECONOMIST: Jaw-jaw beats nuclear war | The

The Bureau of Ocean Energy Management requested that NOAA investigate the site after it was originally detected as an "unknown sonar contact" by Shell Oil Company during a 2011 oil and gas survey of the Gulf, government officials said.

CNN: STORY HIGHLIGHTS

Jaradat suffered from back pain and had been injured in the past by a rubber bullet and tear gas canister, the Shin Bet statement said, adding that he was examined a few times by a doctor who detected no health problems, and his interrogation continued.

NPR: Palestinian Prisoners Strike After Inmate Death