[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] 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

[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)

No abstract available

[en] A pseudo-curved neutron monochromator with a continuously variable curvature was constructed with four flat pieces of oriented pyrolytic graphite (OPG). Curvatures which yield maximum diffracted intensities were determined for neutrons of wavelengths 1 A and 2.4 A. The increase of the intensity relatively to that of a flat monochromator is by a factor of 2 and 1.5, for 1 A and 2.4 A, respectively. The neutron flux at three positions along the neutron path was determined by gold foils activation and compared with the flux from flat monochromators of OPG and copper

[en] We have fabricated and tested water jet cooled silicon (111) and (220) monochromators specially tailored for extended wiggler beam and concentrated undulator beam power loadings. The tests were made at the X25 27 pole, 1.1 T hybrid wiggler beam line¹ at the National Synchrotron Light Source (NSLS). The wiggler-like line-type loading was produced by the direct, unfocused wiggler white beam, in which 300 W of total power in a 60-mm-wide by 5-mm-high [full width at half maximum (FWHM)] cross section were available in the experimental hutch; this represents a typical power density at existing insertion device beam lines. The undulator-like point-type loading was produced by the focused wiggler white beam, generated via reflection of a portion of the direct white beam from a toroidal platinum-coated silicon mirror, resulting in 75 W of total power in a 0.8-mm-wide (FWHM) by 0.45-mm-high (FWHM) cross section in the hutch. This will be a typical power density at next-generation insertion device beam lines