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![[Figure 1]](un5007fig1mag.jpg)
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Figure 1
A schematic demonstration of how the TOF technique at one magnet rotation angle gives data equivalent to those obtained over a range of rocking angles in the single-wavelength technique. The spread of wavelengths in the incident beam is represented by three wavevectors of different lengths. The incoming and outgoing wavevectors ki and kf are labelled for one of these wavelengths. The magnetic field and sample are rotated together away from the incident beam direction by an angle which has been exaggerated for clarity. The rotation angle is chosen so that a VL diffraction spot satisfies the Bragg condition at a wavelength λB in the middle of the incoming wavelength distribution. Thus elastic scattering by 2θB (also exaggerated for clarity) corresponds to a VL reciprocal-lattice vector q, which is perpendicular to the magnetic field. Imperfections in the VL give a finite size to its diffraction spot, represented by the green ellipse, and this gives rise to different correlation lengths parallel and perpendicular to the field. For SANS measurements, the range of wavelengths or the rocking curve give information almost exactly along qz, the component of wavevector parallel to the field. |
![[Figure 1]](un5007fig1.jpg)
 | JOURNAL OF APPLIED CRYSTALLOGRAPHY |
ISSN: 1600-5767
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