Figure 1
(a) The conventional transverse MIEZE setup. (b) The MIEZE setup combined with magnetic Wollaston prisms (MWPs) to correct for the linear Larmor phase from the sample. (c) A schematic of the combined intensity modulation in the time and space domains. (d) The intensity modulation in direct transmission and scattering directions. The lines denote the wavefront, and is the footprint of the sample projected towards the scattering direction, which denotes the effective source size of the intensity modulation. The frequencies of the RF flippers are and the thickness of the RF flipper is δ. The magnetic fields inside the MWPs are
B1,2, respectively.
L1,2 and
D1,2 are the distances from the RF flippers and MWPs to the sample, respectively. The intensity modulation of the neutron beam is developed from the RF flippers in the time domain and a snapshot of the modulation is shown at the sample and detector position for a parallel beam, for the case of without (a) and with (b) the MWPs. s and h are the positions where the neutrons are scattered and captured at the sample and detector, respectively, which have a full width of 2S and 2H, respectively. w is the transverse offset of the neutron's trajectory at the entrance of the slit located at
x = L with a full size of 2W. For demonstration purposes, the dashed trajectories are the ideal case where both the incoming and outgoing neutron beams are parallel to the center trajectory. The solid trajectory shows the actual case in the experiment, which is used in the following calculations. The red dots along the neutron trajectory are the intersection points with various components of the setup, and the corresponding Larmor phase and time at these points are denoted as and
ti, respectively. |