Cutting system assists in Russian nuclear cleanup

The Laboratory is continuing its efforts to assist in the dismantlement of nuclear weapons in the former Soviet Union. In early April, Lab engineers packed a 6.4-m (21-ft) van with a portable "water knife" cutting system designed to permit safe access to warheads and other "hot" materials. The system will be used for standby response in the event of accidents involving the transport of nuclear materials.
Although water knives are not new, adapting a "portable" system is a unique application. The pressure generator alone weighs 771 kg (1700 lb) while the control panels needed for remote use weigh 136 kg (300 lb). To help move the pressure generator, the van has been fitted with a winch; many components have been adapted with lifts that allow assembly by just one person.
The van containing the cutting system was sent to a base near Moscow. Another van containing a second cutting system was shipped from Livermore in early June. In addition, a Laboratory team was dispatched to Russia to provide training in the use of the emergency cutting systems.
Assembly of the vans and cutters has been the work of the Disablement Technology Group in the Laboratory's Nonproliferation, Arms Control, and International Security directorate. The work is part of Department of Energy's efforts in the Safe Secure Dismantlement Program, an international agreement designed to provide assistance and equipment to Russia, Ukraine, Belarus, and Kazakhstan.

Contact: Norm Stewart (510) 243-7768 (stewart8@llnl.gov).

Study suggests aging, genetic damage connection

A study by Lawrence Livermore scientists has found that older people have more DNA damage than younger individuals. DNA is the molecule that carries the body's genetic code. On March 14, James Tucker, senior biomedical scientist, reported the results of the three-year study at the Environmental Mutagen Society's annual meeting in St. Louis, Missouri.
Tucker's research team studied chromosomes in blood samples from a group of individuals ranging in age from 20 to 80 as well as in blood taken from the umbilical cords of newborn infants. The scientists found that genetic damage increased with age and shot up dramatically after age 50. "We expected to observe more genetic damage in older people, and this seems to indicate that damage can accumulate through normal living," said Tucker.
The most common type of damage observed was translocations, where chromosomes break and recombine with other chromosomes. Translocations were found more than 10 times as often in people over the age of 50 than in newborns.
Tucker said the results will benefit researchers studying the effects of radiation on people by providing a baseline against which genetic damage in exposed individuals can be measured.

Contact: James Tucker (510) 423-8154 (tucker5@llnl.gov).

Radar licensee, AlliedSignal, to develop auto system

Amerigon Inc. of Monrovia, California, has announced an agreement under which AlliedSignal Inc., one of the auto industry's largest electronics suppliers, will join in the development of an auto radar system based on LLNL technology.
Amerigon Inc. holds the license from the Lab to use the radar advance, called Micropower Impulse Radar, for automotive safety applications. Amerigon plans possible applications of the radar as a device to signal when vehicles are in a driver's blind spot, as a backup warning system, as a parking aid, and for triggering side-impact air bags.
The new technology was invented by Livermore engineer Tom McEwan in connection with his work for the Lab's Nova laser. The radar has been used as a part of a system to measure the balance and power output of the laser's 10 beams and as the heart of the diagnostics that measure neutrons from the fusion reactions.
For $10 to $15 in off-the-shelf components, the Micropower Impulse Radar can do the same tasks as equipment costing $40,000. Since the new radar technology was announced in March 1994, the Laboratory has received over 2000 calls from businesses and individuals in at least 15 nations.

Contact: Tom McEwan (510) 422-1621 (mcewan@llnl.gov).

Goal is to spot small, covert nuclear tests

Laboratory researchers are attempting to develop an improved method for identifying covert nuclear tests. Current identification techniques are efficient at identifying detonations of 150 kilotons or greater, the yield limit imposed by the Threshold Test Ban Treaty. They are not able, though, to differentiate effectively between small evasive nuclear tests and other seismic events, such as earthquakes or mining activity. Conceivably, proliferant nations might test with smaller nuclear devices to take advantage of the fact that small explosions are more difficult to identify.
One promising identification method being explored by Lab researchers compares two kinds of seismic waves--called P and S waves--generated by both earthquakes and nuclear explosions and looks for differences in the size of their spectral ratios at many frequencies. A spectral ratio is the ratio of the spectral amplitudes of two signals such as a P and S wave.
A weakness of the approach is that it probably would not be able to discriminate between large-scale concentrated chemical explosions and small nuclear detonations, according to Peter Goldstein, the principal investigator working on the detection technique for the Lab's Nonproliferation, Arms Control, and International Security directorate. However, efforts are under way to develop techniques for identifying such explosions.

Contact: Peter Goldstein (510) 423-1231 (peterg@llnl.gov).

Lab and MIT operate tokamak via Internet

Laboratory scientists teamed up with colleagues from the Massachusetts Institute of Technology recently to demonstrate the first transcontinental operation of a fusion experiment via the Internet. Using a Department of Energy subnet of the global Internet known as the Energy Sciences Network, managed from Livermore, MIT scientists successfully operated the Alcator C-Mod reactor in Cambridge over ESnet. On the first full day of remote experiments, 21 of 35 shots were controlled from Livermore.
Although aimed at proving the technical feasibility of running a tokamak remotely, the LLNL-MIT Internet collaboration also allowed scientists to learn more about managing the efforts of research groups working at the same time in different locations on joint equipment.
"This demonstration was the definitive test of controlling a large, complex physics experiment from a remote location," says physicist Tom Casper, who leads the Laboratory's effort in the collaboration. "This technology is important not only to fusion, but also to other scientific applications--such as medical systems or environmental work--where real-time access and control are needed from various locations around the country."

Contact: Tom Casper (510) 422-0787 (casper1@llnl.gov).

Researchers explore MACHOs in dark matter

An international team of scientists reports that Massive Compact Halo Objects, or MACHOs, constitute less dark matter in the Milky Way than was previously thought possible. One conclusion is that some other unknown type of object makes up the dark matter. On the other hand, the findings may mean that the current model for the halo of dark matter in our galaxy is inaccurate. The findings are reported in the April 10 issue of Physical Review Letters.
In their search for MACHOs, the team observed three microlensing events instead of the 15 that were expected if MACHOs made up all of the ubiquitous dark matter. Microlensing is the brightening of a star that indicates the passage of a large object in front of it, thereby magnifying, as if through a lens, the light passing around the object. The September 20, 1993, issue of Nature called this group's first observation of microlensing, which garnered worldwide attention, the "footprint of dark matter."
The MACHO collaboration, which consists of 18 researchers from eight institutions, is funded in part by the Laboratory. For the past two years, the collaboration has monitored some 8.6 million stars in the Large Magellanic Cloud with sophisticated camera systems, each of which contains 16 million pictures, The search for dark matter will continue for at least three years at the great Melbourne Telescope at Mount Stromlo Observatory near Canberra, Australia.

Contact: Charles Alcock (510) 423-0666 (alcock@igpp.llnl.gov).