New science from instrument and technique advances
11 Nov 2009



As well as larger instrument developments, advances in techniques or in other experimental equipment also enable new science to be done using neutrons and muons at ISIS. 



Simultaneous neutron and Raman scattering

ISIS now has the capability to make simultaneous neutron and Raman scattering measurements at temperatures between 1.5 and 450 K. Raman measurements with a resolution of 1-4 cm-1 can be made over a wide wavelength range (100 – 3200 cm-1) at the same time as a variety of neutron scattering measurements. The new equipment has been used for inelastic neutron scattering and neutron diffraction in conjunction with Raman for studies of the globular protein lysozyme.

raman scattering

Mark Adams and Stewart Parker (ISIS) setting up the Raman spectrometer for simultaneous neutron measurements.
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Putting the squeeze on energetic materials

The recent development of a compact variable temperature insert for the Paris-Edinburgh pressure cell has allowed study of the high-pressure, high-temperature structural behaviour of the widely used explosive RDX. The structures of three forms of this material have been characterised for the first time.  Information obtained under the extreme conditions typical of those experienced during explosive decomposition is very important for modelling the performance and characteristics of energetic materials.

putting the squeeze

The Paris-Edinburgh pressure cell equipped with the compact variable-temperature insert. The cell allowed observation of the molecular conformation change when the alpha-form of RDX is transformed into the epsilon-form at high pressure (5 GPa) and temperature (500 K).
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Making supercritical CO2 thicker

A new Thar pressure cell has been used to great effect on Loq.  The improved efficiency of the cell has allowed Eastoe et al., (Bristol), to study designer, low-cost hydrocarbon surfactants as fluid modifiers for supercritical carbon dioxide (sc-CO2).  Small angle neutron scattering has shown these surfactants form hydrated reverse micelles in sc-CO­2 which could be used to unlock the full potential of CO2 as a green solvent.

supercritical co2

Sarah Rogers (ISIS) preparing the new Loq pressure cell.
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Spectroscopic neutron analysis facility for archaeological objects

A new facility based on neutron resonance capture analysis (NRCA) and neutron resonance transmission (NRT) has been installed at ISIS.  This is part of the EU Ancient Charm project, which aims to develop science research techniques for cultural heritage objects. NRCA and NRT use epithermal neutrons for non-destructive bulk analysis and for mapping of elements in archaeological objects. The equipment can potentially be used also for cross section measurements of reference materials and nuclear materials.  This work is a collaboration between G Gorini and E Perelli Cippo (Milano-Bicocca, Italy), P Schillebeeckx (IRMM Geel, Belgium), and W Kockelmann and E Schooneveld (ISIS).

spectroscopic neutron analysis

Schematic of the neutron resonance capture and transmission detectors for the INES instrument.
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A flow-through quartz cell with gas flow control system

A flow-through quartz gas cell, together with its complementary flow control and monitoring system, has been developed by ISIS in collaboration with Chalmers University of Technology, Sweden. This equipment allows neutron powder diffraction data to be collected on samples at temperatures up to around 1300 K when exposed to mixtures of O2, Ar, CO2 and CO.  For example, the cell has been used to probe the crystal structure of CeO2-δ, which has applications in solid oxide fuel cells, as a function of oxygen partial pressure.

X-ray diffraction for disordered materials

The ISIS Disordered Materials Group are now running a laboratory x-ray diffractometer, optimised for structural studies of liquids, glasses and disordered crystals. The aim is to provide x-ray diffraction data which will complement the data obtained on the group’s neutron diffractometers, GEM, Nimrod and Sandals, by virtue of the different contrasts for the two radiations. Currently the diffractometer is nearing the end of a period of scientific commissioning, after which it will be available for approved disordered materials experiments by ISIS users.

x-ray diffraction

Nattapol Laorodphan (Warwick University) preparing the new x-ray diffractometer.
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