Layout

NCD-SWEET beamline optical layout with the main components. Below, a more detailed information is provided.

The chosen optical layout is aimed at delivering high-photon flux onto the sample: The source is an in-vacuum undulator (IVU21) with 21.6 mm period and 93 periods. A channel cut Si (111) monochromator is used to obtain the monochromatic X-ray beam with a ∆E/E of 2.7·10^-4 at 10.0 keV. Then, the X-ray beam is collimated with an array of 3, 6, or 9 Be lenses. A set of microfocussing Be lenses is also available to focus the X-ray beam on the sample position, obtaining a beam size of 4 × 10 µm² (V × H) at 12.4 keV. Along the beamline, several 4 sets of slits vertical and horizontal slits are used to define and clean the X-ray beam. Before the sample, an in vacuo fast shutter is placed that only opens if data acquisition is demanded, minimizing the sample irradiation unless needed.

Component	Distance from source
IVU21 unudlator center	0 m
Channel cut monochromator Si (111)	21.893 m
Collimating Be lenses	24.333 m
Microfocussing Be lenses	32.034 m
Sample position	32.5 m
Beamline last point (window flange)	32.659 m
Sample position	~ 32.7 m (flexible)
(GI)SAXS Sample-Detector distance	2.1 m - 7.5 m
GIWAXS Sample-Detector distance	50 mm - 300 mm

Check the sample environment site to learn about the modular positioning system and sample environment.

Source: In-vacuum undulator (IVU21)

The NCD-SWEET beamline is tunable over a wavelength range of 0.62Å - 1.90Å and delivers a high-photon flux onto the sample, the beam has an excellent beam collimation and photon density, and is also highly stable. For this purpose the photon source of this beamline is an undulator, IVU21, placed in a medium 4 m straight section.

Material	Sm₅Co₁₇ pure permanent magnet
Period	21.6 mm
Number of periods	93
K at minimum gap	1.6
Photon source size	309 x 18 µm² (H x V, FWHM)
Photon source divergence	112 x 28-22 µrad² (H x V, FWHM)

Monochromator: Si (111) channel-cut

The beamline is equipped with a Si(111) channel-cut monochromator for energy selection.

Material	Si
Reflection	(111)
Lattice Spacing	3.1356 Å
Geometry	Channel-cut
Gap between crystals	6 mm
Energy range	6 - 20 keV
ΔE/E @ 10 keV	2.7·10^-4

Optics: Be Compound Refractive Lenses (CRLs)

The beamline is equipped with interchangeable sets of 3, 6, or 9 beryllium CRLs for beam focusing/collimation.

Assembly	3, 6 or 9 Be CRLs
Material	Be
Radius of curvature	200 µm
Aperture	820 µm

Optics: Microfocus Be CRLs

The beamline is equipped with a microfocus CRL stack (33 beryllium lenses) for tight beam focusing.

Assembly	33 lenses
Material	Be
Radius of curvature	100 µm
Aperture	419 µm