Journal of Neutron Research - Volume 3, issue 2

Authors: Sears, V.F.

Article Type: Research Article

Abstract: The scattering of thermal neutrons in non-magnetic materials is due almost entirely to the strong (i.e. nuclear) interaction between the neutrons and the nuclei, and the primary role of electromagnetic interactions is in magnetic materials, where the magnetic dipole interaction between the neutrons and the magnetic electrons gives a contribution to the scattering that is normally comparable in magnitude to that from the nuclear interaction. Nevertheless, even in a non-magnetic material, there exist other kinds of electromagnetic interactions between the neutrons and the atoms which give a small (typically 1%) contribution to the effective bound coherent scattering length. This contribution …is, however, wave-vector dependent and is often one or two orders of magnitude larger than the current experimental uncertainty in the nuclear part of the scattering length. The purpose of this article is to call attention to the existence of these other electromagnetic interactions, to demonstrate that they are important in many kinds of scattering experiments and should be taken into account in the analysis of the data, and to describe two simple ways to correct for them, either of which should be adequate for most purposes. Show more

DOI: 10.1080/10238169608200191

Citation: Journal of Neutron Research, vol. 3, no. 2, pp. 53-62, 1996

Authors: de Haan, V.-0. | van Well, A.A.

Article Type: Research Article

Abstract: A comparison is made between a time-of-flight neutron reflectometer and a monochromatic neutron reflectometer, both installed at the same continuous neutron source. It is shown that the measuring times, to obtain similar results, are approximately the same.

DOI: 10.1080/10238169608200192

Citation: Journal of Neutron Research, vol. 3, no. 2, pp. 63-68, 1996

Authors: Hagen, M. | Steigenberger, U. | Petrillo, C. | Sacchetti, F.

Article Type: Research Article

Abstract: The triple axis spectrometer (TAS) has long been the mainstay for measuring excitations in single crystal samples. In a recent paper Dorner has claimed that the TAS would be the instrument of choice for such measurements at any future high flux spallation neutron source. However, a comparison of the operational characteristics of a TAS and those of direct and indirect geometry time of flight spectrometers for this type of measurement at a pulsed source shows that the TAS would not in fact be a particularly competitive instrument for this purpose.

DOI: 10.1080/10238169608200193

Citation: Journal of Neutron Research, vol. 3, no. 2, pp. 69-92, 1996

Authors: Petrillo, C. | Sacchetti, F. | Steigenberger, U. | Hagen, M.

Article Type: Research Article

Abstract: The results of test measurements carried out at the ISIS spallation source on a prototype double-crystal analyser system are reported. Based upon the results of these test measurements, a multi-double-crystal analyser system has been designed for use on the PRISMA spectrometer and is under construction at the Istituto di Struttura della Materia del Consiglio Nazionale delle Ricerche, Frascati, Italy. This new analyser system will allow experiments to be carried out on PRISMA with low analysing energies (Ef,min = 2.25meV).

DOI: 10.1080/10238169608200194

Citation: Journal of Neutron Research, vol. 3, no. 2, pp. 93-103, 1996

Authors: Por, P.T. | Rekveldt, M.TH. | Fredrikze, H.

Article Type: Research Article

Abstract: A general formulation of the three polariser – two shim method, using the spin density formalism, is described. Using this method, the polarising power of neutron polarisers or polarising samples can be separated from the depolarisation in the set-up composed of three neutron polarisers. The applications and limitations of this method are discussed in the field of polarised neutron scattering, polarised neutron reflectometry and neutron depolarisation.

DOI: 10.1080/10238169608200195

Citation: Journal of Neutron Research, vol. 3, no. 2, pp. 105-124, 1996