D33

Massive dynamic q-range small-angle diffractometer

Guide hall n°1, cold guide H142

Wavelength Definition
Monochromatic Mode:
Velocity selector (Astrium)	Δλ/λ = 10 % (standard)
Wavelength range	4.5 < λ/Å < 40 (for Δλ/λ = 10 %)
Time-of-Flight (TOF) Mode:
4-chopper system (Astrium)
Wavelength cut-offs	14 Å and 20 Å
Wavelength resolutions	Δλ/λ = 2 % to 26 % (depending on chopper pair & detector distance)

Collimation
4 movable guide sections	2.5 m
Beam nose	2.8 m
Guide cross-section	30 x 30 mm
Source-to-sample distances (m)	2.8, 5.3, 7.8, 10.3, 12.8
Source apertures	30x50 mm (off-centre), 30x30 mm diameters: 5, 10, 20, 30 mm

Sample area
Maximum flux at sample (for Δλ/λ = 10%)	4.1x10⁷ n cm^-2 s^-1
Brightness (flux / unit solid angle)	3.57x10¹¹ n cm^-2 s^-1 strd^-1
Maximum sample dimensions	15 mm x 15 mm
Sample environments	Sample changer, Electromagnet, Cryostat, Cryomagnet, Furnace, Stopped-flow, Shear cell

Detectors
Sample - Detector distances	1.2 ... 12.8 m
Detector 1 (rear):
Single panel monoblock	640 x 640 mm
Pixel size	5 x 5 mm² (128 x 128 pixels)
Maximum count rate	4 MHz (global) ; 3 kHz/pixel (local)
Detector 2 (front):
4-panel monoblock	160 x 640 mm each panel
Pixel size	5 x 5 mm² (32 x 128 pixels)
Maximum count rate	4 MHz (global) ; 3 kHz/pixel (local)

Instrument Description

Scientific goals

Modern trends in materials science, physics and in particular nano-structured materials require that D33 provides both high resolution and a wide dynamic range of measured scattering vector, q.

Description

The instrument offers both ‘monochromatic’ and ‘time-of-flight’ (TOF) mode.
Monochromatic mode: a velocity selector and flexible system of inter-collimation apertures defines the neutron beam.

TOF mode: a chopper system allows an enhanced dynamic q-range (q_max / q_min) and flexible wavelength resolution.
Two large multitube detectors extend the dynamic q-range further giving q_max / q_min = 20 in monochromatic mode and massive q_max / q_min > 1000 in TOF mode.

Beam polarization and ³He spin analysis facilitate and expand studies of magnetism and allow a more quantitative analysis of spin incoherent samples. The position of D33 allows high magnetic fields and bulky environments at the sample position.

Ref.:

"The small-angle neutron scattering instrument D33 at the Institut Laue–Langevin", Dewhurst C.D., Grillo I., Honecker D., Bonnaud M., Jacques M., Amrouni C., Perillo-Marcone A., Manzin G., Cubitt R., Journal of Applied Crystallography 49, 1-14 (2016)