London: In a significant breakthrough,
scientists have isolated an exotic radioactive gas which they
claim would make it easier to detect underground nuclear tests
from air samples.
A global network of monitoring stations constantly
samples the air for signs of underground nuclear tests. One
thing the stations look for is the radioactive gas xenon-133.
Nuclear explosions produce an excited form
called xenon-133m, in which the atomic nucleus is boosted to a
higher-energy state, but it is not known exactly how sensitive
detectors are to this form as there has been no way to make
pure samples of xenon-133m with which to test them.
Now, Kari Perjrvi of Radiation and Nuclear Safety
Authority in Finland has solved the problem.
The team placed a cloud of xenon-133 atoms inside a
magnetic trap and then jolted it with oscillating electric and
magnetic fields; this pushed out the unexcited form, leaving
only the excited form behind, the `New Scientist` reported.
The work could make nuclear monitoring with air
samples more reliable, according to the findings published in
the `Applied Radiation and Isotopes` journal.
But James Acton of the Carnegie Endowment for
International Peace in Washington has said that the gas may
stay trapped below ground if there are no cracks for it to
seep through, making on-site visits -- not currently required
by international law -- a better approach.