Upgrade of the Cold Neutron Imaging Instrument, Phase Grating Roll Alignment System
COMMERCE, DEPARTMENT OF
About this opportunity
The NIST neutron imaging team, in the Radiation Physics Division of the Physical Measurement Laboratory, is developing a far-field grating neutron interferometer to measure the projection of the pair correlation function, G(Z), of a sample of interest. This interferometer geometry requires precision alignment of 3 gratings about the roll direction of the neutron beam. Since G(Z) is a vector quantity, aligned perpendicular to the grating direction, the grating alignment stages need to be able to rotate a full 360�, with high resolution. The gratings are lines etched into silicon wafers, where the period of the lines is of order 1 micrometer and the wafers are 100 mm in diameter. The mass of a grating, including a holder is of order 100 g. The interferometer pattern is measured by translatin...