PHYS01200804001 Sohrab Abbas - Homi Bhabha National Institute

(A=16 o and θ S =−51 o ) for 5.26 Å neutrons (theory) and its convolution with the
monochromator angular profile of Fig.33. 69
Fig.35 SUSANS experimental arrangement of the optimised monochromator-analyser pair
of Si {111} Bragg prisms. A translation of the monochromator chooses between
its Bragg reflection and prism diffraction to illuminate the analyser. Cd sheet
downstream of the analyser can be translated to allow or forbid the analyser Bragg
reflection into the detector (not shown). 71
Fig.36 Photographs of Bragg prisms. Top: Monochromator-analyser setup. Bottom: Three
monochromators and one analyser (3 rd from the left). 73
Fig.37 Bragg reflection from the θ S =53.5 o monochromator observed with prism diffraction
(cf. inset) of the optimal analyser. 75
Fig.38 Bragg reflection rocking curve of the monochromator (A=172 o and θ S =50.1 o )
observed with Bragg reflection and prism diffraction (cf. inset) of the optimal
analyser. 76
Fig.39 Bragg Prism diffraction rocking curve of monochromator (A=172 o and θ S =50.1 o )
observed with Bragg reflection and prism diffraction (cf. inset) of the optimal
analyser. 76
Fig.40 1 st sub-arcsec neutron collimation: observed (data points) and calculated (curve)
rocking curves (cf. inset) for prism diffractions of the monochromator (A=172 o and
θ S =50.1 o ) and the optimal analyser. 77
Fig.41 SUSANS spectra without and with a sample holder, viz. a pair of overhead projecttion
transparencies. 78
Fig.42 First Q ~ 10 -6 Å -1
SUSANS spectra without and with a Hydroxyapatite casein