D4 - Disordered Materials Diffractometer

D4, a two-axis diffractometer, uses short-wavelength neutrons from the hot source to measure diffraction patterns over a large Q-range.  Combining very high counting-rate stability with very low background counts, D4 can determine the local atomic structure of disordered materials (liquids, amorphous solids, nano-structured materials, disordered crystals) with excellent accuracy.

• Short and intermediate range order in liquid, amorphous and nano-structured materials.
• Isotopic substitution methods for resolving partial structure factors.
• Magnetic structure studies on very absorbent systems, such as those containing Gd, Eu, etc.
• Pair-Distribution Function (PDF) analysis of powder diffraction patterns.

A large array of microstrip detectors provides not only a high counting rate but also a very good counting-rate stability.  Combined with a very low+stable background counting rate, D4c (the present version of the D4 instrument) is thus well-adapted for high-accuracy measurements on small samples, and for sensitive difference measurements as in the case of small scattering-length contrast.

D4 shares the beam tube H8 with the IN1 triple-axis and Lagrange (Be-filter) spectrometers, and is therefore available for only about 50 % of the time.