[en] The monochromator according to the invention is characterized by a plane support that does not absorb neutrons, and on which are deposited layers of two different metals, such as germanium and manganese, the thickness of which permits to achieve desired neutron-diffusion densities with a view to focusing a narrow neutron beam onto a detector. Such a monochromator is suitable, in particular, for determining the arrangement of atoms in a complex lattice, e.g. of myoglobin, sciatic nerve fibers, or the like

[en] Removing the contamination of high order neutrons from the pyrolytic graphite (PG) monochromator is one of the most critical procedures to obtain reliable data on a thermal tripleaxis spectrometer (TAS). This is typically done by putting a PG filter after the sample in the fixed-Ef configuration, which results in many restrictions in the experiments. We have built the Bamboo thermal TAS at China Advanced Research Reactor (CARR), Beijng, China. By installing a neutron velocity selector before the PG monochromator, the incident neutrons are free of unwanted higher neutrons. It allows us to continuously fine tune the energy and momentum resolution in a simple manner. In addition, it provides much more choices in an experiment that may significantly improve the data quality.

No abstract available

[en] A simple technique is described for optical absorption measurements under various conditions, by converting a grating monochromator to a double-beam instrument

[en] Since the development of Laue Photographic Method, it became worthwhile to more quantitatively evaluate the neutron power diffracted on a film, and we thought to extend such calculation to the neutron power sent into samples by monochromators. This last problem is not very easy and some aspects, like the use of a correct expression for the extinction phenomena, the connection between extinction and collimation, the possible use of composite monochromators and the comparison between monochromator working in reflexion and in transmission, are studied

[en] Reflecting properties of a double-crystal (DC) monochromator consisting of two elastically bent perfect silicon crystals in the parallel non-dispersive (1,-1) setting were experimentally treated. Using an unconventional fully asymmetric geometry, the effective mosaicity may be significantly enhanced up to the value of about 10^-2 rad. Test experiments were performed on the 111 and 400 reflections for wavelengths of 0.2 nm and 0.157 nm, respectively. The experimental results obtained are found to be in good agreement with the theoretical predictions published in a previous paper. (orig.)

No abstract available

[en] Various focusing monochromators are compared and evaluated for use in an EXAFS spectrometer. For a line focus the Johann and Johansson case are found to be most suitable. Obtaining a point focus is more difficult, with the best case appearing to be a singly bent mirror used in conjunction with the Johann or Johansson crystals

No abstract available

[en] A curved neutron monochromator composed of 145 small Cu platelets is described. Focusing in the horizontal and vertical directions may be achieved. Compared with a flat monochromator an intensity gain of more than one order of magnitude is observed. A monochromator of this type is mainly used for diffuse scattering work. (author)