Cold neutrons are converted to ultra-cold neutrons (UCN) by the excitation of a single phonon or multiphonons in superfluid helium. The dynamic scattering function S(q, ω) of the superfluid helium strongly depends on pressure, leading to a pressuredependent differential UCN production rate. A phenomenological expression for the multiphonon part of the scattering function s(λ) describing UCN pro...

The excitation of the isovector giant dipole resonance (GDR) by alpha scattering is investigated as a method of probing the neutron excess in exotic nuclei. DWBA calculations are presented for 28 O and 70 Ca and the interplay of Coulomb and nuclear excitation is discussed. Since the magnitude of the Coulomb excitation amplitude is strongly influenced by the Q–value, the neutron excess plays an ...

FLAC is a program to calculate the small-angle neutron scattering intensity of highly packed polydisperse systems of neutral or charged hard spheres within the Percus-Yevick and the Mean Spherical Approximation closures, respectively. The polydisperse system is defined by a size distribution function and the macro-particles have hard sphere radii which may differ from the size of their scatteri...

The distribution of divalent ions in semidilute solutions of high-molecular-mass DNA containing both sodium chloride and strontium chloride in near-physiological conditions is studied by small-angle x-ray scattering and by small-angle neutron scattering. Both small-angle neutron scattering and small-angle x-ray scattering reveal a continuous increase in the scattering intensity at low q with in...

We report polarized neutron scattering studies of spin-wave excitations and spin fluctuations in the S=5/2 kagomé lattice antiferromagnet KFe3(OH)6(SO4)2 (jarosite). Inelastic polarized neutron scattering measurements at 10 K on a single crystal sample reveal two spin gaps, associated with in-plane and out-of-plane excitations. The polarization analysis of quasi-elastic scattering at 67 K shows...

The recent developments of the neutron scattering instruments at the DR3 10 MW steady state reactor and other related facilities at Risø National Laboratory are described. The motivation for starting these developments is to optimise the available cold and thermal neutron flux as cost effective as possible. This has led to the implementation of the RITA neutron spectrometer and the germanium mo...

This article is concerned with the use of quasielastic neutron scattering as a technique for investigation of the dynamical properties of proton conducting oxides. Currently, the main interest in these materials comes from their promise as electrolytes in future electrochemical devices and particularly through their use as electrolytes in next-generation, intermediate-temperature, fuel cells. H...

We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering. In the last week of the course, students travel to a large-scale neutron scattering facility to perform ...

2014 The use of small angle neutron scattering (SANS) for the study of systems under non-equilibrium conditions is illustrated by three types of experiments in the field of polymer research : 2014 the relaxation of a system from an initial non-equilibrium state towards equilibrium, 2014 the cyclic or repetitive installation of a series of non-equilibrium states in a system, 2014 the steady non-...

The practical calibration rooms for neutron measuring devices are relatively small, where a large amount of room-reflected neutrons arise. Moreover the different structures of neutron irradiation apparatus influence the neutron spectrum and reference dose considerably. Therefore the influence of the neutron scattering was investigated in the three calibration rooms in different sizes and instal...