The external neutron beam line at OSURR is able to deliver a relatively-clean, small-sized (< 30 mm diameter) thermal neutron beam to a workbench, where various instruments can be set up for detector evaluation and in-situ materials characterization. The neutron collimator consists of single-crystal sapphire and polycrystalline bismuth filters (providing fast neutron and gamma-ray filtration, respectively) followed by a parallel series of 3-cm apertures for collimation. The thermal-equivalent neutron flux is ~4x106 n/cm2/s at the sample position, which is an optical table upon which instrumentation may be set up for in-situ testing of radiation detectors or coupons may be set up for characterizing materials, and ~2x106 n/cm2/s in the high-vacuum chamber. See the facility fluxes page for present values. The cadmium ratio, which is defined as the ratio of the activities of bare and cadmium-covered gold foils detectors and which characterizes the epithermal and fast neutron contributions in the neutron spectrum, was measured to be 92.
See OSU's Nuclear Analysis and Radiation Sensor (NARS) Laboratory site for more information.