On-Line Test Facility (OLTF)
The On-Line Test Facility (OLTF),
formerly known as University Isotope Separator at Oak Ridge (UNISOR),
is used to develop targets and ion
sources for the production of radioactive ion beams (RIB).
The OLTF is composed of a target/ion source station on a
beamline from the 25 MV tandem accelerator, a 90-degree mass separation
magnet having a mass resolution of m/Δm = 2000, and three experimental
endstations. The three endstations include a moving tape system,
with a Ge detector, which is used to measure the radioactive ion beam
intensity; a Cs-vapor charge exchange cell to measure negative-ion
formation efficiencies, including formation of negative ions from
positively-charged molecules; and the multi-pass time-of-flight
spectrometer, which is being developed as a high-resolution mass filter.
At the HRIBF, radioactive ion beams are produced using the ISOL technique, where light-ion beams (isotopes of hydrogen and helium) irradiate a thick target and radioactive nuclei are produced via nuclear reactions with the target nuclei. For tests at the OLTF, the production beams from the 25 MV tandem accelerator are delivered to the production target, such as silicon carbide, hafnium oxide, uranium carbide, and many others. Production beams that are normally used include 40 MeV protons up to 50 nA, 40 MeV deuterons up to 25 nA, and 66 MeV alphas up to 100 nA. Beams of heavier nuclei can also be delivered to the OLTF target station. The radioactive nuclei diffuse out of the target material and are transported to the ion source where a 50 kV beam is extracted and delivered to the experimental endstations. Experiments at the OLTF can be performed with beams of negative ions or positive ions, depending on which type of ion source is preferred. In addition to target and ion source development, radioactive ion beams can be, and have been, provided to study decay properties of short-lived nuclei using an array of Ge detectors and an electron spectrometer.
For questions about this page please contact the HRIBF User Liaison.
This file last modified Monday January 08, 2007