Search results for "neutron reflectometry"
showing 10 items of 12 documents
Cubic boron nitride: A new prospective material for ultracold neutron application
2009
Abstract At the ultracold neutron (UCN) source of the TRIGA research reactor in Mainz, we have measured for the first time the material optical wall-potential of cubic boron nitride. The measurements were performed with a time-of-flight (TOF) spectrometer. The samples investigated had a wall-potential of ( 305 ± 15 ) neV . This value is in good agreement with the result extracted from neutron reflectometry data and theoretical expectations. Because of its high critical velocity for UCN and its good dielectric characteristics, cubic boron nitride coatings (isotopically enriched) will be useful for a number of applications in UCN experiments.
Structural Characterization of Molecular Interface Layers Using Neutron and X-Ray Reflectivity Techniques
1992
Synthetic microstructures used in biological research today include a variety of different systems that serve very diverse purposes and require very different fabrication and characterization techniques. One class of microstructures that is at the boundary between life and materials sciences, and certainly has been associated closer to the latter in the past, is that of molecularly structured planar interface films. In fact, Langmuir-Blodgett (LB) films,1 i.e. molecularly layered films comprised of amphiphatic organic molecules on solid substrates, have been used for many years as model systems for the investigation of molecular interactions between chromophores or donor/ acceptor couples, …
Neutron Scattering in Nanomagnetism
2015
Abstract Polarized neutron reflectometry (PNR) has played an essential role for the exploration of nanomagnetic and spintronic materials, including exchange coupled magnetic superlattices, exchange bias systems between ferromagnetic and antiferromagnetic films, spin valves, exchange springs between soft and hard magnetic films, superconducting proximity effects, periodic lateral magnetic patterns, and magnetic nanoparticles. The main virtues of PNR are depth-resolved vector magnetometry in the film plane, high sensitivity to magnetic interfaces, and statistical analysis of magnetic domain fluctuations. Recently the capabilities of PNR have been carried over from steady state to dynamic inve…
Determination of the Composition of Mixed Hydrogenated and Fluorinated Micelles by Small Angle Neutron Scattering
1997
On the formation of inclusion complexes at the solid/liquid interface of anchored temperature-responsive PNIPAAM diblock copolymers with γ-cyclodextr…
2017
The thermal responsive behavior of adsorbed layers of diblock copolymers of poly(N-isopropylacrylamide) (PNIPAAM) and poly((3-acrylamidopropyl)trimethylammonium chloride) (PAMPTMA(+)) with γ-cyclodextrin (γ-CD) at the solid/liquid interface has been investigated using three in situ techniques: null ellipsometry, quartz–crystal microbalance with dissipation monitoring, and neutron reflectometry. The measurements provided information about the adsorbed amounts, the layer thickness, hydration and viscoelastic properties, and the interfacial structure and composition. The copolymers adsorb to silica with the cationic PAMPTMA(+) blocks sitting as anchors in a flat conformation and the PNIPAAM ch…
Neutron scattering study of melting ofHe3surface layers
1982
The melting of the incommensurate phase of $^{3}\mathrm{He}$ submonolayers adsorbed on Grafoil was investigated by elastic neutron scattering. The temperature dependence of the nearest-neighbor distance, the coherence length, and the peak intensity of the structure factor can be explained by a simple model assuming a melting transition which is driven by thermally created lattice defects.
A new method for data evaluation of small angle neutron scattering experiments and its application to amorphous polycarbonate
1981
The conformation of single chains in bulk polymer materials can be evaluated from coherent neutron scattering on mixtures of normal and deuterated polymers. It is shown that the single-chain structure factor can be also obtained from measurements of highly concentrated mixtures and the procedure of evaluation is described. The application to amorphous polycarbonate demonstrates the advantages of the method.
Mono- and Multi-Layers
2006
Thin films incorporating or consisting of calixarenes have been widely investigated. The capacity of such films to adsorb both ions and neutral species has engendered particular interest in their use in sensor devices. Semiconductors, non-linear optical and pyroelectric materials or switchable systems for data storage are further examples of their potential use [1]. Both monoand multi-layer films can be formed from calixarenes and resorcarenes, using a variety of techniques. This chapter deals with the fundamental basis of calixarene thin film applications, including film formation and characterisation as well as studies of selectivity in small molecule interactions. Real and potential appl…
Fractal approach in petrology: Combining ultra small angle (USANS), and small angle neutron scattering (SANS)
2000
Ultra small angle neutron scattering instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering instruments on one side and optical microscopy on the other side. Rocks showing fractal behavior in over two decades of momentum transfer and seven orders of magnitude of intensity are examined and fractal parameters are extracted from the combined USANS and SANS curves.
The Swelling Behavior of Polyelectrolyte Multilayers in Air of Different Relative Humidity and in Water
2002
The swelling properties of physisorbed polyelectrolyte multilayer self-assemblies with alternating polyion charge in humid air and in aqueous environment were investigated via X-ray and neutron reflectometry as well as optically, using surface plasmon spectroscopy. The sorption behavior was similar to that found for neutral polymers and was related to an internal screening of the charges of the adjacent layers owing to the high entanglement of the polyelectrolyte chains and the resulting low mobility of the polymer segments. The screening was found to be incomplete only in the top layer, resulting in a net charged surface.