OAK RIDGE, Tenn., Aug. 30, 1996 -- A final milestone reached at the Holifield Radioactive Ion Beam Facility (HRIBF) means that researchers from around the world will soon begin using this facility to study nuclei that cannot be produced from elements that exist on Earth.
Researchers today generated the first radioactive ion beam at the Department of Energy (DOE) facility at Oak Ridge National Laboratory (ORNL). By this fall, scientists from universities and laboratories around the world will be conducting experiments they hope will answer questions about nuclear physics and nuclear astrophysics. The first of its kind facility provides a resource for unique challenges.
"The HRIBF is the only facility in the world dedicated to the acceleration of radioactive ion beams with sufficient intensity and energy to be useful for nuclear physics and nuclear astrophysics," said Jerry Garrett, scientific director of the Holifield facility. "It will serve a national and international community of about 300 scientists from 33 states and 20 foreign countries, providing a unique new tool for understanding nuclear matter, the main constituent of the visible universe."
Experiments in nuclear astrophysics will likely account for about a third of the experiments using the radioactive ion beam. These studies will focus on understanding nova and supernova, the spectacular stellar explosions that produce all the heavy elements, including the carbon, nitrogen and oxygen that make life on Earth possible. Most of the remaining beam time will be devoted to studying the structure of exotic nuclei that exist for just a fraction of a second.
Typical experiments will run from a few days to a few weeks, according to Garrett, who said the beam will be available about 2,500 hours a year. Usually, just one experiment can be done at a time; however, sometimes two nuclear structure experiments can run concurrently.
Already, Garrett has received 16 proposals for experiments from 54 researchers at 22 institutions within the U.S. and beyond. Annual beam time is limited because of maintenance activities involving the facility's components, which consist of two accelerators (the world's largest electrostatic accelerator and a cyclotron) and a high-voltage radioactive ion injector.
Workers completed physical construction of the facility in September 1995 -- on time and within budget, Garrett said. Researchers produced the first stable (non-radioactive) beam in late October 1995 and have been commissioning, or fine-tuning, the facility over the past several months.
Reconfiguration of ORNL's former Holifield Heavy Ion Research Facility began in mid-1992 after DOE funded an ORNL Physics Division proposal outlining new physics opportunities obtainable with no major civil construction and minimal cost. A total of $2.6 million was provided by DOE's Nuclear Physics Program Office over a four-year period ending last year.
ORNL, one of DOE's multiprogram research laboratories, is managed by Lockheed Martin Energy Research Corporation.