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Both Differential Scanning Calorimetry (DSC) and Quasi-elastic Neutron Scattering (QENS) are powerful analytical tools actively used in studies of phase transitions in complex solid and liquid systems. DSC is typical­ly used to map phase transition temperatures and identify sample states, and QENS provides information on the molecular scale dynamical motions, such as molecular self-diffusion or glassy dynamics, associated with such transitions. Both techniques provide highly valuable complementary information about the sample and in many cases it would be advantageous to measure in parallel with a view to linking the two observables. The biggest challenge is that the cell design which differs greatly between the two methods. Here we present a first attempt at designing a cryogenic system which will allow the simultaneous measurement of calorimetric transitions and QENS measurements, as tested on the neutron spectrometer IRIS at ISIS neutron scattering facility. The system temperature range is from 10 K to 300 K. We present and discuss the initial design of the system, preliminary test results, current challenges and limitations, and future directions.Both Differential Scanning Calorimetry (DSC) and Quasi-elastic Neutron Scattering (QENS) are powerful analytical tools actively used in studies of phase transitions in complex solid and liquid systems. DSC is typical­ly used to map phase transition temperatures and identify sample states, and QENS provides information on the molecular scale dynamical motions, such as molecular self-diffusion or glassy dynamics, associated with such transitions. Both techniques provide highly valuable complementary information about the sample and in many cases it would be advantageous to measure in parallel with a view to linking the two observables. The biggest challenge is that the cell design which differs greatly between the two methods. Here we present a first attempt at designing a cryogenic system which will allow the simultaneous measurement of calorimetric transitions and QENS measurements, as tested on the neutron spectrometer IRIS at ISIS neutron scattering facility. The system temperature range is from 10 K to...

Blue series top-loading furnaces are regularly used at neutron facilities to carry out experiments at up to 1700∘C. The sample temperature is controlled using the indirect resistance heating method which consists in placing the sample inside a radiating cylindrical heater made from vanadium or niobium into which a current of up to 180 A circulates. To prevent the oxydation and deterioration of the heated elements, the sample, the heater and the heat shields are in a secondary vacuum which limits very much the cooling rate. We present an automated fast-cooling technique which reduces the cool-down time by a factor of 4 to 5 without impacting the lifetime of the heated elements. This method is now routinely used at the ILL and ISIS facilities and reduces very much beam time losses.

We describe the capability to measure high-resolution neutron powder diffraction data to a pressure of at least 8 kbar. We have used the HRPD instrument at the ISIS neutron source and a piston-cyli...

The archetype cubic chiral magnet MnSi is home to some of the most fascinating states in condensed matter such as skyrmions and a non-Fermi liquid behavior in conjunction with a topological Hall effect under hydrostatic pressure. Using small angle neutron scattering, we study the evolution of the helimagnetic, conical and skyrmionic correlations with increasing hydrostatic pressure. We show that the helical propagation vector smoothly reorients from $\langle 111 \rangle$ to $\langle100\rangle$ at intermediate pressures. At higher pressures, above the critical pressure, the long-range helimagnetic order disappears at zero magnetic field. Nevertheless, skyrmion lattices and conical spirals form under magnetic fields, in a part of the phase diagram where a topological Hall effect and a non-Fermi liquid behavior have been reported. These unexpected results shed light on the puzzling behavior of MnSi at high pressures and the mechanisms that destabilize the helimagnetic long-range order at the critical pressure.

We have developed and realised a compact high-pressure clamp cell of the piston-cylinder type for Small Angle Neutron Scattering (SANS) and Neutron Spin Echo (NSE) spectroscopy measurements. The cell can pressurise φ5 mm samples up to 1.5 GPa. It is non-magnetic, produces a sufficiently low and flat SANS background with a relatively good neutron transmission and can be used in combination with polarised neutrons. The cell accommodates samples of up to 55 mm3 in volume and adopts a two-layer geometry: a TiZr body (outer layer) and a CuBe2 insert (inner layer). Its design is very compact and can be employed inside cryomagnets featuring a sample bore greater than φ30 mm. We present the cell and illustrate its performances with a series of neutron scattering experiments performed on single-crystalline MnSi.

We discuss an experimental approach to determine the concentration of para-H2 in the hydrogen moderators serving the Target Stations 1 and 2 at ISIS. The outcome of the measurements based on this approach is crucial for the Target Station 1 project, where a detailed characterisation of the present performance is needed to test neutronics simulations. The approach described here is based on the measurement of neutron transmission spectra over a wide energy range of samples extracted from the moderators. Pilot experiments were performed on the VESUVIO spectrometer at ISIS and were combined with measurements of thermal conductivity of the same samples using the ISIS para-H2 rig.

Positions of elastic plastic interfaces play a vital role in safe design and safe use of high pressure vessels. The ENGIN-X neutron diffractometer at the ISIS facility was used to measure the residual strain profiles in a series of aluminium vessels which had been subjected to different pressure levels. The positions of elastic plastic interfaces of the autofrettaged pressure vessels were identified. The results revealed that the residual strain magnitude and the depth of the plastic region will increase with increasing autofrettage pressure level. When autofrettage pressure produces an elastic-plastic boundary at a greater depth than the geometric mean position of the vessel wall, reverse yielding will occur, hence the loss of the vessels’ elastic ability to its subsequent loading. The neutron experimental results agreed well with both the suggestions from existing literatures and the results from FE simulations.

The development and testing of a gas-pressurized μSR setup for the RIKEN-RAL Muon Facility is reported. In collaboration with the high-pressure group of the ISIS Facility at the Rutherford Appleton Laboratory, a gas-pressurized setup for a pulsed muon beam at the RIKEN-RAL Muon Facility has been constructed in 2008. The sample is pressurized by helium gas and the designed maximum pressure is 6.4 kbar. The high-pressure cell can be cooled down to 2 K using an existing cryostat. Tests were made injecting the double-pulsed muon beam into a high-purity sample of Sn powder, which confirmed that the maximum pressure achieved at 2 K was close to the designed pressure.

Refinements to established sample handling issues connected with the acquisition of inelastic neutron scattering (INS) spectra of heterogeneous catalyst samples are described. This involves modification of a reactor and improvements to gas handling apparatus. The latter includes provision of laboratory space and ventilation facilities that are suited to the increasingly wide range of catalytic samples being examined. INS measurements for CO hydrogenation over an iron-based Fischer-Tropsch catalyst recorded using the MARI spectrometer are presented to illustrate the applicability of the new arrangements.

The idea of using hydrogen as a fuel has gained immense popularity over many years. Hydrogen is abundant, can be produced from renewable resources and is not a greenhouse gas. However development of hydrogen based technology is impossible without understanding of physical and chemical processes that involve hydrogen sometime in extreme conditions such as high pressure or low and high temperatures. Neutron spectroscopy allows measurement of a hydrogen atom motion in variety of samples. Here we describe and discuss a sample environment kit developed for hydrogen gas experiment in a broad range of pressure up to 7 kbar and temperatures from 4 K to 473 K. We also describe para-hydrogen rig which produces para-hydrogen gas required for studying the rotational line of molecular hydrogen.

The ENGIN-X beamline is a dedicated engineering science facility at ISIS optimized for the measurement of strain, and thus stress, deep within crystalline materials using the atomic lattice planes as an atomic 'strain gauge'. Internal stresses in materials have a considerable effect on material properties including fatigue resistance, fracture toughness and strength. The growing interest in properties of materials at high temperatures may be attributed to the dynamic development in technologies where materials are exposed to a high-temperature environment for example in the aerospace industry or fission and fusion nuclear reactors. This article describes in detail the design and construction of a furnace for neutron scattering measurements of internal stress in engineering materials under mechanical load and in elevated temperature environments, designed to permit a range of gases to provide a non-oxidizing atmosphere for hot samples.

High-pressure research is one of the fastest-growing areas of natural science, and one that attracts as diverse communities as those of physics, bio-physics, chemistry, materials science and earth science. In condensed matter physics there are a number of highly topical areas, such as quantum criticality, pressure-induced superconductivity or non-Fermi liquid behaviour, where pressure is a fundamental parameter. Reliable, safe and user-friendly high pressure gas handling systems with gas pressures up to 1GPa should make a significant impact on the range of science possible. The ISIS facility is participating in the NMI3 FP7 sample environment project supported by the European Commission which includes high pressure gas cell development. In this paper the progress in designing, manufacturing and testing a new generation of high pressure gas cells for neutron scattering experiments is discussed.

Inelastic neutron scattering (INS) is increasingly being used for the characterization of heterogeneous catalysts. As the technique is uniquely sensitive to hydrogen atoms, vibrational spectra can be obtained that emphasize a hydrogenous component or hydrogen-containing moieties adsorbed on to an inorganic support. However, due to sensitivity constraints, the technique typically requires large sample masses (∼10 g catalyst). A reaction system is hereby described that enables suitable quantities of heterogeneous catalysts to be appropriately activated and operated under steady-state conditions for extended periods of time prior to acquisition of the INS spectrum. In addition to ex situ studies, a cell is described which negates the need for a sample transfer stage between reaction testing and INS measurement. This cell can operate up to temperatures of 823 K and pressures up to 20 bar. The apparatus is also amenable to adsorption experiments at the gas-solid interface.

A flow-through quartz gas cell, together with a gas flow control and monitoring system, has been designed and constructed at ISIS. This equipment allows neutron powder diffraction data to be collected on samples at temperatures up to around 1300 K when exposed to user chosen mixtures of O2, Ar, CO2, and CO. By exploiting the sensitivity of neutrons to the presence of light atoms such as oxygen, it is possible to probe the crystal structure of oxide materials as a function of oxygen partial pressures down to log 10p(O2) of about -20. The resultant structural information can then be correlated with the bulk properties of the materials, whose research and technological interests lie in fields such as energy production, storage materials, catalysis, and earth science.

An in situ cell that allows the electrical resistance of a sample pellet to be measured while performing neutron diffraction experiments has been developed at the ISIS pulsed neutron source. The sample is held between two spring loaded platinum electrodes embedded in a boron nitride clamp assembly with the resistance measured using the four-probe method. An outer quartz glass jacket allows the atmosphere within the sample enclosure to be controlled, and the entire device can be accommodated within a standard ISIS neutron furnace for measurements at temperatures up to 1270 K. The operation of this cell is illustrated using data for the structural, magnetic, and electrical properties of chalcopyrite CuFeS(2) collected over the temperature range of 398-873 K on the Polaris powder diffractometer at ISIS.