Oct. 21, 2002

Rensselaer Researchers To Build New Device To Analyze Fission Fragments

	Thomas Griffin

Rensselaer will design a sophisticated detector to help scientists and engineers simulate accurately the performance of nuclear devices.

Supported by a government grant of more than a half-million dollars, the design and development of the detector will be led by Assistant Professor Yaron Danon '90 (far right in photo) and Professor Emeritus Robert Block (left) of the Department of Mechanical, Aerospace, and Nuclear Engineering.

The detector will provide vital data on certain nuclear reactions with extremely small (sub-microgram) amounts of fissionable materials that cannot be measured today. Those data are essential if scientists are to simulate the performance of nuclear devices in lieu of actual testing.

Used in conjunction with Rensselaer's Lead Slowing Down Spectrometer (LSDS) — the only such device in the United States — the new detector will gather fundamental data on nuclear fission.

Built in the 1970s, the LSDS is a 75-ton cube of pure lead. Pulsed by the electron beam from the Institute's linear accelerator (LINAC), the LSDS can create an extremely high-neutron flux that can interact with very tiny amounts of a test material.

"We will first test the new detector using uranium 235," said Danon. "The fission products of U-235 are well known. If our readings correspond to well-corroborated data, we will confirm the detector is working accurately."

The Rensselaer-designed detector will ultimately be used at Los Alamos National Laboratory (LANL) where they are considering building another LSDS. Using the LSDS, the new Rensselaer detector, and their high-intensity neutron spallation source, LANL scientists will gather data on such materials as meta stable U-235m, an important isotope with a half-life of only 26 minutes. The Rensselaer detector will be able to provide a complete picture of all the fission fragments, including the energy, mass, charge, and angular distributions.

"We will be taking this research to a much higher level than any of the work ever done in the past," Block said.