Physics News Update #182
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Number 182, June 8, 1994 by Phillip F. Schewe and Ben Stein
RADIOACTIVE ATOMS HAVE BEEN TRAPPED using a combination of
laser beams and magnetic fields. Luis Orozco and his colleagues at Stony Brook
produced rubidium-79 isotopes and sent them into a glass cell, where the atoms
bounced back and forth between special non-stick walls until they rebounded slowly
enough to become captured by the magneto-optical trap at the center of the cell.
A Berkeley team led by Stuart Freedman slowed down a beam of sodium-21 atoms
with lasers before the atoms entered the magneto-optical trap. In efforts to learn how
to trap atoms efficiently, Michelle Stephens and Carl Wieman at the University of
Colorado released stable cesium atoms into a cell, also with non-stick walls, and
succeeded in holding 6% of the atoms at a time. The Colorado researchers predict
that collection efficiencies can be as high as 50% for atoms in an optimal magneto-optical
trap. The Stony Brook and Colorado groups are each interested in studying the phenomenon
known as parity violation in radioactive isotopes, while the Berkeley group is interested in
making precise measurements of beta decay. (G. Gwinner et al., Z-T. Lu et al., and M. Stephens
et al., Physical Review Letters, 13 June 1994.)
ONLY 21% OF HIGH SCHOOL STUDENTS ENROLL IN PHYSICS in the U.S.,
even though 98% of students go to schools that offer physics classes. By comparison,
nearly 50% of students take chemistry. "Physics in the High Schools," the second in a
series of reports issued by AIP, reveals that only 15% of female students and 10% of black
and Hispanic students take physics. About 1% of all students take a second year of physics.
In the wake of the 1983 report "Nation at Risk," many states raised their high school requirements
from one to two years of science, but this has had little impact on physics enrollment since physics
is still traditionally offered only after students take biology and chemistry. In 1989-90, the most
recent year sampled in the AIP report, 620,000 high school students were enrolled in physics
classes in the U.S. About 18,300 teachers---only 27% of whom had college physics
degrees---taught physics. Among these, 96% were white, 2% black, 1% Hispanic, and 1%
Asian. (For more information, contact Michael Neuschatz, AIP Statistics Division, 301-209-3077.)
RUSSIA'S 3-TeV PROTON ACCELERATOR, under construction
at the Institute of High Energy Physics (IHEP) in Protvino, may not be completed.
Like many scientific ventures in the former Soviet Union, the project is starved for funds.
Much of the accelerator's 21-km tunnel has been built and many of the needed magnets
have been tested and stockpiled, but there now appears to be no more money for finishing
the machine. Other physics labs, such as the Institute of Theoretical and Experimental
Physics (ITEP) and the Kapitsa Institute (prominent in low-temperature research) in Moscow
are close to collapse. At the Joint Institute of Nuclear Physics (JINR) in Dubna, things are
somewhat better, partly because of the continued collaboration with scientists from the former
Soviet republics and from Germany. (Science, 27 May.)
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