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November 2002

The Laboratory
in the News

Commentary by
Leland W. Younker

This Model Can Take the Heat

The Best and the Brightest Come to Livermore

A View to a Kill

Biological Research Evolves at Livermore

Patents

Awards

 

The Laboratory
in the News

Radiation detectors tested, developed
Livermore researchers are testing commercial instruments and developing new technologies to detect nuclear materials inside cargo containers. Funded by the National Nuclear Security Administration, this work aims to prevent the smuggling of nuclear materials into the U.S. by airplane, ship, rail, or truck.
In June, Laboratory researchers tested 19 commercially available handheld instruments that government agencies are using or might use to detect nuclear materials in cargo containers.
“One of our areas of expertise is understanding what goes into a nuclear weapon, so we know how to test equipment to find the materials for which different government agencies are searching,” says William Dunlop, leader of Livermore’s Proliferation Prevention and Arms Control Program.
Livermore researchers, experienced in designing and testing nuclear weapons, have assessed possible improvised nuclear devices as part of the Laboratory’s nonproliferation programs, according to Dunlop. This expertise is bolstered by the program’s capabilities in detecting trace elements.
Livermore and other researchers are also developing new and enhanced radiation detection systems. One new device is Cryo3, a mobile, handheld detector. Developed by researchers at Lawrence Livermore and Lawrence Berkeley national laboratories, Cryo3 is a high-resolution germanium detector cooled mechanically by a compact, low-power microcryocooler instead of by liquid nitrogen. Once the device has been tested and approved for field use, the Laboratory will help train personnel in using the new technology.
Contact: William Dunlop (925) 422-9390 (dunlop1@llnl.gov).

New facility puts the pressure on materials
In July 2002, the High Pressure Collaborative Access Team (HP-CAT) began work on the newest research facility at the Advanced Photon Source (APS) at Argonne National Laboratory in Illinois. This $10-million research facility will contain beamlines for the intense, high-energy APS. Researchers will use the facility to study in high resolution the structure and behavior of materials under high pressures and varying temperatures.
HP-CAT is made up of Livermore’s High-Pressure Physics Group from the Physics and Advanced Technologies Directorate; the High Pressure Science and Engineering Center at the University of Nevada at Las Vegas; the Carnegie Institution of Washington Geophysical Laboratory in Washington, D.C.; and Argonne National Laboratory.
Funded in part by the Department of Energy’s Office of Defense Programs and Office of Science and scheduled for completion by May 2003, the new research facility will advance high-pressure science by allowing new types of experiments to be performed. For example, scientists will be able to measure the dynamics of electrons, atoms, and nuclei of complex materials as functions of pressure, temperature, and time. It will also allow the use of new-generation high-pressure devices such as large-volume diamond-anvil cells. Its goals are to advance high-pressure synchrotron radiation research and establish a leading center of high-pressure research accessible to the scientific community at large.
“At Livermore, we’ve invested in this beamline because it is an enabling capability for the Stockpile Stewardship Program,” says William Goldstein, associate director for Physics and Advanced Technologies. “The highly intense, high-energy x-ray beam will allow us to characterize the structure of high explosives and of the low-symmetry phases of plutonium with unprecedented precision.”
Contact: Choong-Shik Yoo (925) 422-5848 (yoo1@llnl.gov).

Age of oldest objects in solar system determined
A team of geochemists, including Livermore’s Ian Hutcheon, has accurately dated calcium–aluminum inclusions (CAIs), the oldest objects in our solar system, at 4.57 billion years old. The team also determined that chondrules, another of the earliest objects in the solar system, are 2 to 3 million years younger than CAIs. “By determining the age of CAIs and chondrules, we can better date asteroids and planets and learn more about the early history of the solar system,” says Hutcheon.
Hutcheon, Yuri Amelin of the Royal Ontario Museum, Alexander Krot of the University of Hawaii, and Alexander Ulyanov of Moscow State University published their findings in the September 6, 2002, issue of Science.
Using mass spectrometers to study CAIs and chondrules, the team determined the age of the objects by measuring the decay rate of uranium-238, which is found in both objects, as it decays into lead. With an ion microprobe, Hutcheon then dated CAIs and chondrules by detecting the decay of aluminum-26, also found in both objects, into magnesium-26.
Aluminum-26 decays much faster than uranium-238. By comparing the lead and magnesium isotope content in the CAIs and chondrules, the team determined with great precision both how old the objects are and the difference in age between CAIs and chondrules.
CAIs and chondrules are millimeter-size objects found in primitive meteorites. They formed when dusty regions of the solar nebula were heated to high temperatures. The dust melted and then crystallized, forming first CAIs and then chondrules.
Larger objects, such as asteroids and planets, took longer to form and are about 10 to 50 million years younger than CAIs and chondrules.
Contact: Ian Hutcheon (925) 422-4481 (hutcheon1@llnl.gov).


 



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UCRL-52000-02-10 | November 15, 2002