Neutron spectrometer scan

Fig. tt.5-2tta,b BaTiOs. Triple-axis neutron spectrometer scans at constant frequency across the sheet of diffuse scattering at 150 °C. The path of the scans is shown in the inset, (a) shows the elastic scan (v = 0), where the high background level is due to nuclear incoherent scattering, (b) Ineleastic scan (v = 0.97 x 10 Hz)... 

The SCANS is used in conjunction with an analytical system such as a portable Raman spectrometer or a portable isotopic neutron spectrometer to identify the agent inside a vial or bottle so the correct reagent can be selected to neutralize it. A 4-liter bottle of reagent is placed in the reactor case,... 

Inert sampling could be done when desired. Zr, W and Ni were determined by XRF, Ti and Cr by neutron activation analysis (NAA), Mg by AAS, C with a Leco carbon analyzer and Cl by potentiometric titration. FTIR in diffuse reflectance mode was used to follow the chemisorption and to detect possible decomposition of the reactant. Scanning electron microscopy with an energy dispersive spectrometer (SEM/EDS) was used to determine element concentrations through the particles. The specific surface area and pore volume were determined by means of nitrogen adsorption and condensation with Micromeritics ASAP 2400 equipment. Detailed experimental conditions used in the characterization are in Ref. 16. 

The pulsed-source equivalent of a triple-axis spectrometer is demonstrated by PRISMA at ISIS. The difference is that a white beam of neutrons is incident on the sample, rather than a monochromated beam. As in the triple-axis spectrometer, Bragg reflection from analyser crystals is used to select the neutrons scattered by the sample that will ultimately be detected. However, PRISMA has an array of 16 independent analyser and detector arms instead of just one detector. Each arm of PRISMA measures along a parabolic path in (Q, w) space, so generating a two-dimensional scan through (Q, co) space for each ISIS pulse, in a single setting of the instrument and sample. 

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