ORNL Researcher Hassina Bilheux explains the ability of SNS to explore the internal structure of ... more ORNL Researcher Hassina Bilheux explains the ability of SNS to explore the internal structure of a 3D-printed turbine blade.
Neutron imaging offers deep penetration through many high-Z materials while also having high sens... more Neutron imaging offers deep penetration through many high-Z materials while also having high sensitivity to certain low-Z isotopes such as 1H, 6Li, and 10B. This unique combination of properties has made neutron imaging an attractive tool for a wide range of material science and engineering applications. However, measurements made by neutron imaging or tomography are generally qualitative in nature due to the inability of detectors to discriminate between neutrons which have been transmitted through the sample and neutrons which are scattered by the sample or within the detector. Recent works have demonstrated that deploying a grid of small black bodies (BBs) in front of the sample can allow for the scattered neutrons to be measured at the BB locations and subsequently subtracted from the total measured intensity to yield a quantitative transmission measurement. While this method can be very effective, factors such as the scale and composition of the sample, the beam divergence, and...
A ``volume''-type ECRIS, based on the flat central-fiel... more A ``volume''-type ECRIS, based on the flat central-field (flat-B) concept, has been developed at the Holifield Radioactive Ion Beam Facility, Oak Ridge National Laboratory. The superiority of the ``volume-type'' ECRIS concept over its conventional minimum-B source counterpart, in terms of higher charge-state and intensity within a particular charge-state, has clearly been demonstrated. As evidenced by comparing X-ray spectra for the
An all-permanent, 6 GHz ECR ion source has been constructed at the Holifield Radioactive Ion Beam... more An all-permanent, 6 GHz ECR ion source has been constructed at the Holifield Radioactive Ion Beam Facility (HRIBF), Oak Ridge National Laboratory (ORNL), that permits configuration of the central magnetic field in either conventional parabolic or flat minimum-B profiles. The magnitude of the central flat field configuration extends over an axial region of ~ 2 cm to form a large and uniformly distributed ECR volume. The capability of operating the source in either volume or surface modes permits direct comparison of the performances of each source type. The studies show that the volume ECR source produces higher charge-states and higher intensities within a particular charge-state than does the surface form of the source. The X-ray spectra derived during operation of the source also suggest that the enhanced performance of volume ECR source is attributable to its ability to accelerate a larger population of electrons to higher energies than its conventional counterpart.
ORNL Researcher Hassina Bilheux explains the ability of SNS to explore the internal structure of ... more ORNL Researcher Hassina Bilheux explains the ability of SNS to explore the internal structure of a 3D-printed turbine blade.
Neutron imaging offers deep penetration through many high-Z materials while also having high sens... more Neutron imaging offers deep penetration through many high-Z materials while also having high sensitivity to certain low-Z isotopes such as 1H, 6Li, and 10B. This unique combination of properties has made neutron imaging an attractive tool for a wide range of material science and engineering applications. However, measurements made by neutron imaging or tomography are generally qualitative in nature due to the inability of detectors to discriminate between neutrons which have been transmitted through the sample and neutrons which are scattered by the sample or within the detector. Recent works have demonstrated that deploying a grid of small black bodies (BBs) in front of the sample can allow for the scattered neutrons to be measured at the BB locations and subsequently subtracted from the total measured intensity to yield a quantitative transmission measurement. While this method can be very effective, factors such as the scale and composition of the sample, the beam divergence, and...
A ``volume''-type ECRIS, based on the flat central-fiel... more A ``volume''-type ECRIS, based on the flat central-field (flat-B) concept, has been developed at the Holifield Radioactive Ion Beam Facility, Oak Ridge National Laboratory. The superiority of the ``volume-type'' ECRIS concept over its conventional minimum-B source counterpart, in terms of higher charge-state and intensity within a particular charge-state, has clearly been demonstrated. As evidenced by comparing X-ray spectra for the
An all-permanent, 6 GHz ECR ion source has been constructed at the Holifield Radioactive Ion Beam... more An all-permanent, 6 GHz ECR ion source has been constructed at the Holifield Radioactive Ion Beam Facility (HRIBF), Oak Ridge National Laboratory (ORNL), that permits configuration of the central magnetic field in either conventional parabolic or flat minimum-B profiles. The magnitude of the central flat field configuration extends over an axial region of ~ 2 cm to form a large and uniformly distributed ECR volume. The capability of operating the source in either volume or surface modes permits direct comparison of the performances of each source type. The studies show that the volume ECR source produces higher charge-states and higher intensities within a particular charge-state than does the surface form of the source. The X-ray spectra derived during operation of the source also suggest that the enhanced performance of volume ECR source is attributable to its ability to accelerate a larger population of electrons to higher energies than its conventional counterpart.
Journal of Materials Science.
Three brass sestertius coins from the reign of Gordian III were im... more Journal of Materials Science. Three brass sestertius coins from the reign of Gordian III were imaged at the Oak Ridge National Laboratory’s neutron imaging beam, CG-1D, at the High Flux Isotope Reactor. Tomography results showed a gradual variation in neutron attenuation from one side of the coins to the other or toward the center of the coin. Linear neutron attenuation values calculated from the neutron radiographs, as well as micro-XRF results, suggest that this gradual variation in neutron attenuation is associated with elemental segregation within the coins. The difference in segregation patterns between the coins implies two types of casting methods were utilized to form the coins—vertical and horizontal casting methods.
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Papers by Hassina Z Bilheux
Three brass sestertius coins from the reign of Gordian III were imaged at the Oak Ridge National Laboratory’s neutron imaging beam, CG-1D, at the High Flux Isotope Reactor. Tomography results showed a gradual variation in neutron attenuation from one side of the coins to the other or toward the center of the coin. Linear neutron attenuation values calculated from the neutron radiographs, as well as micro-XRF results, suggest that this gradual variation in neutron attenuation is associated with elemental segregation within the coins. The difference in segregation patterns between the coins implies two types of casting methods were utilized to form the coins—vertical and horizontal casting methods.