General topics of interest center around investigation of the structure, dynamics (vibrational and diffusive), and composition (speciation) of molecules at interfaces and in other confining geometries (layers and porous media). Length and time scales of interest are typically probed by neutron scattering techniques such as quasielastic neutron scattering, inelastic neutron scattering, SANS, and...

We report the first measurement of the low-energy neutron-(3)He incoherent scattering length using neutron interferometry: b_{i};{'} = (-2.512 +/- 0.012 stat +/- 0.014 syst) fm. This is in good agreement with a recent calculation using the AV18 + 3N potential. The neutron-(3)He scattering lengths are important for testing and developing nuclear potential models that include three-nucleon forces...

Neutron scattering is a powerful and direct means for investigating the vibrational, magnetic, and structural properties of materials. In this paper, I will present a brief introduction to neutron scattering. I will discuss why neutrons are important, how and where you get neutrons, and types of neutron scattering. This paper is meant as brief introduction into an interesting field of science t...

For neutron scattering research that is performed under extreme conditions, such as high static pressures, high-strength metals that are transparent to the neutron beam are required. The diffraction of the neutron beam by the metal, which follows Bragg’s law, can be completely removed by alloying two metallic elements that have coherent scattering lengths with opposite signs. An alloy of Ti and...

The Gaerttner LINAC Center at RPI uses a 60 MeV electron linear accelerator to produce short pulses of neutrons with duration of 5-5000 ns. The main research thrust at the Center is nuclear data for nuclear reactors and criticality safety applications. The Center includes several setups for time-of-flight measurements including neutron transmission, capture and scattering detectors, and a lead ...

In the theory of resonant scattering, the double differential cross section involves the computation of a multifold integral of a 4-point correlation function, which generalizes the traditional 2-point correlation function of Van-Hove for potential scattering. In the case of a neutron-crystal interaction, the numerical computation of these multifold integrals is cumbersome. In this paper, a new...

The large spin dependence of the absorption cross section for neutrons by He gas provides a method to polarize neutron beams. For certain applications, such polarized He-based neutron ”spin filters” have advantages over conventional neutron optical polarizing methods. Spin filters operate at all neutron wavelengths, can cover a large angular range and/or a large energy range, and decouple neutr...

We report on the construction of an apparatus to allow neutron scattering measurements on fluids undergoing shear. The apparatus has been used with the cold neutron small-angle-neutron-scattering (SANS) spectrometer at the NIST research reactor and will be made available to users as a permanent part of the NIST facility.

Two types of ultra high energy resolution neutron scattering instruments, the backscattering spectrometer and the spin echo spectrometer, are described. Examples of the types of research which can be done with these instruments are given and plans for a cold neutron backscattering spectrometer which will be built in the NIST Cold Neutron Research Facility (CNRF) are discussed. It is hoped that ...

Unlike x-ray generators, neutron sources have inherently low bri ghtness, and care must be exerted in the design of neutron scattering instruments and their coupling to the source to ensure optimal use of the beam. We present a general, versatile Monte Carlo tool for the computer simulation of neutron optics and neutro n scattering instruments that allows a user to produce computer models of an...