New Polarized Neutron Imaging Capability at Oak Ridge National Laboratory

Polarized Neutron Imaging (PNI) visualizes magnetic field distribution through interactions between the neutron polarization and the magnetic field. The PNI technique creates unique imaging contrast related to magnetic properties in comparison to traditional absorption-based neutron imaging. Furthermore, quantitative PNI provides a nondestructive measurement on internal magnetic structures. At the Oak Ridge National Laboratory, a new PNI capability was implemented on the CG-1D neutron imaging beamline at the High Flux Isotope Reactor (HFIR). The PNI setup at ORNL uses an in-situ optical pumping ³He neutron spin filter to provide a non-distorted radiographs with a stable 90% neutron polarization. The polarized beamline operates in either polychromatic or monochromatic mode, with a field of view of 50mm×50mm and 350μm spatial resolution. Based on the new capability, a series of experiments were performed investigating the magnetic field distortion caused by Meissner effect of superconductors. The results of these experiments combined with modeling will be presented. The PNI team at ORNL is now seeking collaborations to utilize the PNI technique at CG-1D.