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Excitations

Measuring vibrations and excitations in matter

Team

Main Contact

• Prof Stephen Bennington

Other Contacts

• Dr Devashibhai Adroja
• Dr Robert Bewley
• Dr Alex Buts
• Dr Russell Ewings
• Dr Christopher Frost
• Dr Tatiana Guidi
• Prof Toby Perring
• Dr Chris Stock
• Dr Ross Stewart
• Dr Jon Taylor

Inelastic neutron scattering can provide rich information about atomic motions and magnetic interactions. Neutron are a weakly interacting probe that do not perturb the system under study, making the results directly comparable to theory.

Our science programme spans a wide range of areas from the investigation of model magnetic systems through to the dynamics of disordered materials and quantum fluids and the dynamics of hydrogen in chemical and biological systems.

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The Instruments

All the instruments are direct geometry instruments where the incident neutron's energy is made monochromatic using one or more choppers. 

		MARI	MAPS	MERLIN	LET
Incident energy (Ei) [meV]		9 - 1000*	15 - 2000	9 - 1000	0.5 - 80
Energy resolution (% of Ei) [meV]	low energy	2.5%	2 - 5%	3 - 5%	0.5 - 1.5%
	high energy	1.5%	1.5%	2%
Q-range   ( x √Ei) [Å-1]	Min:	0.027	0.026	0.026	0.026
	Max:	0.903	0.490	0.906	0.906

^* Note: some test measurements have been done with much higher incident energies (2 - 100eV). This work is still in development, please contact the MARI instrument scientist for details

MARI

MARI has a wide angular coverage and a wide energy range and good resolution making it ideal for the study of disordered systems, chemical spectroscopy and the study of quantum systems, although it does 

MAPS

MAPS has a very large array of position sensitive detectors making it ideal for the study of excitations in single crystals. It has a higher energy and Q-resolution then MERLIN or MARI and its detectors are at lower angles making it ideal for the study of magnetic excitations, although it is also used to measure high energy excitations in molecular systems.

MERLIN

MERLIN has a huge array of position sensitive detectors making it possible to map all the excitations in a Brillouin zone of a single crystal. It was designed to have a very high flux and measure with reasonable energy resolution. It is ideal for measuring dispersive lattice or magnetic excitations, but it is also a high throughput general spectrometer for all kinds of neutron spectroscopy.

LET

LET also has a very large array of position sensitive detectors making it ideal for measuring excitations in single crystals. It is a cold/thermal neutron spectrometer able to measure quasi-elastic neutron scattering as well as lattice or magnon dispersion. It has a very flexible chopper system making it possible to have either very high energy resolution or very high flux.

ALF

ALF is crystal alignment facility to make it possible to co-align multi-crystals, check the quality of crystals or simply pre-align a crystal prior to an experiment. You can request beam time on an application for beam time for any of the ISIS instruments. The instrument is only partially supported and users are expected to have enough experience to be largely self-sufficient after they have been trained on the instrument control and safety procedures.