Figure 4
(a) Theoretical and (b) observed interference generated during the ρ angle alignment. For each ρ value, a neutron-camera image is horizontally integrated yielding a vertical intensity distribution, which is shown here by each pixel column. Concatenating the columns of all ρ values generates the complete image (b). The theoretical pattern (a) perfectly reproduces the observed pattern, although the vertical fringes fluctuate in position and spacing due to phase drifts during the measurement. (c) If the full-beam height is used, the interference is visible only in the vicinity of perfect ρ alignment. The bottom figures in (b) and (c) show the total camera counts. (d) An interferogram created with an auxiliary phase shifter. The red curves are the best sinusoids fitting the data. The fringe visibility is ∼40%. |