Government scientists have developed a next-generation radiation detector that will be cheaper and more accurate than devices now deployed to guard New York and other cities against nuclear terrorism.
A research team at Lawrence Livermore National Laboratory in California announced Wednesday that it has developed a new plastic material that, unlike current detectors, can easily distinguish between gamma rays and neutrons.
Gamma rays commonly come from nonthreatening sources such as stone construction material. Neutrons are telltale indicators of substances like plutonium and enriched uranium that theoretically could be used in improvised nuclear bombs by terrorists, lab officials said.
"We are waiting for full-scale production," said Russian-born Natalia Zaitseva, a materials scientist who was the lead investigator on the project.
Security officials see the development as a boost for the federal Securing the Cities initiative, which has helped buy personal radiation detectors for local police agencies such as the NYPD and Nassau and Suffolk police.
"With al-Qaida's stated objective of obtaining nuclear weapons to use against the West, it is welcome news that Lawrence Livermore has made this breakthrough," New York Police Commissioner Raymond Kelly said in a statement.
Stuart Cameron, chief of the special patrol bureau of the Suffolk police department and an expert on nuclear terrorism, said, "If viable, this will be a great technology and could allow detectors which are smaller and lighter weight."
The breakthrough comes at a good time, Cameron said, because a helium gas used in the current generation of detectors is now in short supply. Laboratory-grown crystals, which are also used, take a long time to develop and can lose effectiveness over time, he noted.
Commissioner Kelly and other officials have often said there is low probability now of a terrorist setting off an improvised nuclear device in the city. More likely, said Kelly, is the use of a dirty bomb -- a conventional explosive that would spew radioactive material such as Cesium-137 over a wide area.
The new material, called a plastic scintillator, does not detect such radioactive isotopes, so existing technology would still be needed. But the new plastic should cut down on false alarms, scientists said.
"This material very, very effectively distinguishes [between] those neutrons that are suggestive of special nuclear material and all that background radiation," said Steve Payne, a scientist from Massapequa Park who also worked on the project.
Zaitseva said the enhanced plastic can be made in sheets as big as six square feet for use at shipping terminals, bridges, tunnels and highways. It can also be used in a new generation of hand-held devices, she said.
LNL officials said two companies are in discussions to manufacture the plastic. Payne said it costs as little as 25 cents to $1 per cubic centimeter to produce, compared with up to $100 for the same-sized crystal.