D10 (Four-circle diffractometer with three-axis energy analysis)

Characteristics

Guide hall n 1, thermal guide H24

Guide
Divergence - supermirror (m=2)	6.9 mrad Å

Monochromator
Vertically focussing and continuously variable
pyrolytic graphite	1.8 < λ < 6 Å
Cu (200)	1.1 < λ < 3 Å
incident energy range	2.5 < Eo< 68 meV
relative energy resolution δE/E	5 x 10-3
absolute energy resolution δE	0.02 THz at ki = 1.55 Å-1
λ/2 contamination	< 2 x 10-4at 1.26 Å with Cu monochromator and no analyser< 10-5at 1.26 Å with Cu monochromator and PG (008) analyser

Sample
beam size	10 x 8 mm2
flux	≥5 x 106cm-2s-1(λ = 2.36 Å; PG-monochromator and filter)≥2 x 106cm-2s-1(λ = 1.26 Å; Cu-monochromator)

Analyser	Analyser
vertically focussing pyrolytic graphite	vertically focussing pyrolytic graphite

Detector
94x94 mm2area detector, or single 3He detectorspacial resolution 1.5 * 1.5 mm2high counting rate
background	< 3 cpm (without analyser)0.5 cpm (with special detector shielding or with analyser)

Scientific Applications

Due to its good momentum resolution with relatively high flux and its low intrinsic background, D10 can be used for all kinds of conventional crystallographic studies of nuclear and magnetic structures. In addition the optional energy analysis allows a restricted energy window to be set to lower the background so that delicate problems, such as Huang scattering, weak diffuse scattering, magnetic multilayers and commensurate-incommensurate phase transitions, can be studied. Inelastic scattering studies, for example of phonon dispersion, may be performed on large samples in both the four-circle and two-axis modes.

Sample Environment

In the four-circle mode, the offset C-shaped Eulerian cradle can be equipped with a helium-flow cryostat (1.6 K to 450 K, or 0.1 K to 10 K in dilution mode), or a hot-air furnace (up to 1000 K), both with full four-circle accessibility. A double-mirror furnace (up to 1800 K in air, in argon, or in vacuum) can be used with access to at least a quadrant of reciprocal space. In the two-axis mode, all standard ILL cryostats, furnaces, pressure cells and cryomagnets can be mounted with computer control of the double-axis tilt stage to allow limited out-of-plane access. Computer control of the temperature is possible for all standard cryostats and furnaces, and of the magnetic field for all standard cryomagnets.

Computing

D10 is controlled by a PC running under Linux. The control program, which can be run via command lines or via an intuitive graphical user interface, is identical to those used on other four-circle and powder diffractometers at the ILL, with additional commands for operation in inelastic mode with syntax familiar to the users of the triple-axis spectrometers.

Data-analysis software includes routines for raw-data display (including LAMP), integration of Bragg reflections, fitting of multi-peaked profiles, and plotting of general sections in reciprocal space, as well as common crystallographic refinement packages for nuclear and magnetic structures (CCSL, shelx, upals, Fullprof), and the display package Cerius.