The results of Monte Carlo simulation and test reflectometry experiments on the "Gorizont" neutron reflectometer (on the IN-06 pulsed neutron source at INR RAS) after its upgrade with a two-dimensional detector with a positioning system are presented. The two-dimensional detector makes it possible to use the instrument not only for neutron reflectometry, but also for small angle neutron scattering. Estimates of the instrument resolution and the spectra of the neutron beam at different collimations have been obtained using Monte Carlo simulation. Test reflectometry experiments have been performed on mirrors with known characteristics. The characteristics match the manufacturer's data with an error of 5%, obtained from the simulation.

Fenghuang has been upgraded to be the first neutron powder diffractometer at the China Mianyang Research Reactor (CMRR) dedicated to research on the microstructure of materials. It was firstly built in 2005 at the Swimming Pool Research Reactor-300 (SPRR-300) in Mianyang, and then moved to CMRR in 2013. Through the combination of a horizontally focusing neutron guide and a vertically focusing monochromator, the neutron flux at the sample position is up to 2.84 × 106 n s−1cm−2. The resolution of the diffractometer can be adjusted by a horizontal slit for different sample. The superposition scan mode enables each detector to measure the complete diffraction pattern and simplifies the correction of the efficiency of the counting channels. This diffractometer is equipped with temperature and pressure devices, and can be used for research at ambient and extreme conditions.

Requirements on the field uniformity in neutron polarizers are analyzed in view of the fact that neutron polarizing coatings have been improved during the past decade. The design of magnetic systems that meet new requirements is optimized by numerical simulations. Magnetic systems for wide-aperture multichannel polarizers and analyzers are represented, including (a) the polarizer to be built at channel 4-4′ of the reactor PIK (Gatchina, Russia) for high-flux experiments with a 100×150mm2 beam of polarized cold neutrons; (b) the fan analyzer covering a 150×100mm2 window of the detector at the Magnetism Reflectometer (SNS, ORNL, USA); (c) the polarizer and (d) the fan analyzer covering a 220×110mm2 window of the detector at the reflectometer NERO, which is transferred to PNPI (Russia) from HZG (Germany). Deviations of the field from the vertical did not exceed 2°. The polarizing efficiency of the analyzer at the Magnetism Reflectometer reached 99%, a record level for wide-aperture supermirror analyzers.

We describe here a new type of wide-angle supermirror-based multichannel analyzer configured in the fan orientation. The increased channel width allows for reflections only from one of the channel's walls, so that the overlap of beams propagating through neighboring channels is avoided. However the straight beam, which is unavoidably propagating through the channels with the increased width, is blocked by an absorbing mask at the entrance of the analyzer. The neutron transmission of such analyzer is 22% higher and the number of the supermirrors needed to cover the same beam cross section is 16% less in comparison with a conventional fan analyzer. Results of the calculations and first tests of the analyzer at the Magnetism Reflectometer at Oak Ridge National Laboratory, USA, are presented.

The basic characteristics of the upgraded DIN-2PI spectrometer are reported. Based on experimental data and numerical calculation results, it is concluded that a supermirror neutron concentrator, with which the DIN-2PI spectrometer is equipped, raises the density of the cold neutron flux at the sample almost by an order of magnitude. The use of a grooved moderator in channel no. 2 and upgrading of the core of the IBR-2M reactor increases the neutron flux density on the sample by about 40% more.

Magnetization reversal of the exchange-coupled granulated ferromagnetic (GF) CoCu and ferromagnetic (F) Co nanolayers is studied by polarized neutron reflectometry. The main parameters that specify the structure and saturation magnetization of the GF and F layers are determined for Si(substrate)/Co0.5Cu0.5(5nm)/Co(x)/Si(3nm) samples with a thickness x varying from 6 to 20 nm. Neutron data allow some suggestions to be made about the features of the GF/F bilayer magnetization reversal. For small x the main mechanism of the magnetization reversal is the domain wall motion hindered by the exchange interaction between GF and F. As a consequence, the magnetization of the Co layer contacting with numerous granules is reversed in fields exceeding its own coercivity by an order of magnitude. For large x the magnetization reversal undergoes several stages conditioned by interaction of GF and F nanolayers. These stages may be characterized by three fields. For an oppositely magnetized sample, when the field approaches H1, there appear regions with flipped moments coupled to non-flipped moments in neighboring regions ("lateral magnetic springs") in the F layer. The field H1 sets off the overturn of magnetic moments of the granules, which is accompanied by the pinning of the regions with reversed magnetization in the F layer. The fields H2 and H3 tag the completion of the overturn of the F layer magnetization and the granule moments, respectively. When the applied field reaches H3, any further change of the magnetic state is due to a reversible rotation of the granule moments and the F layer magnetization. The reversibility of magnetic states persists with fields both increasing above H3 and decreasing down to 0 and further to -H1.

Neutron reflectometry is found to be quite sensitive to oxidation of very thin layers of Ti. Preliminary results of the study of oxidation of thin Ti films in air are represented. The thickness of the oxide layers formed in air at room temperature on Ti films of thickness 20, 10 and 5 nm (as sputtered) is found to be 2.9 +/- 0.3, 3.6 +/- 0.3 and 6.1 +/- 0.3 nm, respectively. The annealing at temperatures in the range 100-300 degrees C leads to the growth in the oxide layer thickness and in roughness of both (air/oxide and oxide/metal) interfaces. The study of the oxidation of thin Ti films is of interest for improvement of polarizing neutron mirrors and supermirrors.

A wide-aperture fan neutron supermirror analyzer of polarization is presented in the paper. The analyzer has been made in PNPI (Gatchina, Russia) for the neutron reflectometer NeRo in GKSS (Geesthacht, Germany). The analyzer is installed in front of the two coordinate position-sensitive detector with sensitive area 250×250mm2. The neutron wavelength is 4.35Å. The analyzer consists of 90 channels, and its entrance cross-section is 90×160mm2. In the paper, the results of tests of the analyzer are presented.

A new large-scale research center for nano diagnostics and neutron and X-Ray studies of nanomaterials is briefly described. This center at the Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS) is based on three specially designed spallation neutron sources driven by primary proton beams. Similar research centers on the basis of the high flux spallation neutron sources are created in the USA, Japan, Great Britain, Switzerland and will be build in China and the EU (Sweden). We discuss neutron and X-Ray instrumentation at the INR RAS and the corresponding domains of research of various materials including nano-systems.

The Gorizont time-of-flight neutron reflectometer—small-angle spectrometer has been designed, manufactured, and assembled to operate with the IN-0 6 pulsed neutron source. The instrument has a vertical neutron scattering plane enabling research on liquid surfaces and interfaces. Model calculations of neutron spectra, beam profiles, and spectrometer resolutions have been performed via the Monte Carlo method. The spectrometer operates at wavelengths from 1.5 to 9 Å and ensures measurements in the momentum-transfer range of 0.003—1.5 Å-1.

A new method for improving polarizing neutron coatings has been verified experimentally. This method is based on the use of Ti interlayers with a negative potential (“antibarrier layers”) at interfacial layers of a polarizing coating for suppressing reflections of neutrons with the undesired spin. It can be expected that the further development of the method will lead to the creation of polarizing neutron supermirrors and multilayer monochromators of a new generation with flipping ratios up to 103. The neutron optics based on these superpolarizing coatings not only will improve the performance and thus extend the range of applications of polarizing devices but also can be the basis for the design of novel neutron instrumentation.

. At the IBR-2 pulsed reactor in Dubna a new neutron Fourier diffractometer FSD is under construction. FSD continues the development of neutron Fourier diffractometry at long-pulse neutron sources, which was started several years ago with the high-resolution Fourier diffractometer HRFD at the IBR-2. Whereas HRFD is mainly used for precise structural refinement, FSD is optimised for internal stress measurements in bulk materials. The FSD design satisfies the requirements of high luminosity, high resolution, a specific sample environment, a wide range of d hkl , and fixed scattering angles 2θ=±90°. It consists of a mirror neutron guide, a fast Fourier chopper for the neutron-beam intensity modulation, a ±90° MultiCon ZnS(Ag) 6 Li-loaded detector system with both geometrical and electronic focusing, a five-axis goniometer ‘Huber’ and loading machines, and VME-based RTOF analysers for data acquisition. Examples of the first experimental results obtained with FSD are presented.

At the IBR-2 pulsed reactor (FLNP, JINR, Dubna), a specialized time-of-flight instrument, the Fourier-Stress-Diffractometer (FSD), is under construction. This instrument is intended for the measurement of internal stresses in bulk samples by using high-resolution neutron diffraction. One of the main components of the diffractometer is a new-type of detector with combined electronic-geometric focusing, uniting a large solid angle and a small geometric contribution to the instrumental resolution. The first two modules of the detector, based on ZnS(Ag)/ 6 LiF scintillation screen with wavelength shifting fiber readout have been developed and tested. In this paper, the design of the detector and associated electronics are described. The method of time focusing surface approximation using the screen flexibility is proposed. Characteristics of tested modules in comparison with a detector of previous generation are presented and advantages of the new detector design for high-resolution diffractometry are discussed.

A few years ago a high-pressure neutron spectrometer DN-12 was created at the IBR-2 pulsed reactor. Neutron diffraction and inelastic incoherent neutron scattering (with samples having large incoherent neutron scattering cross section) experiments at pressures up to 5GPa can be performed with the DN-12 using sapphire anvil cells. After first successful experiments, the development of the DN-12 spectrometer was done during last year. The new parameters and recent experiments performed with the DN-12 both before and after modernization are reviewed.

A new high resolution powder diffractometer has been installed in the site G4.2 of the hall guide of the ORPHEE reactor. The diffractometer is devoted to both crystallographic and magnetic structure determination and refinement. The availability of the three wavelengths (1.8, 2.3, 2.8 Angstrom) makes the diffractometer easily adaptable to the problem to be solved. The peculiarity of this diffractometer is that there are seven independent sections each with ten detectors so that all detectors can pass by the same scattering angle. Such an operating mode simplifies the detectors' efficiency and relative positions.

The first neutron Fourier diffractometer at the pulsed neutron source, the High Resolution Fourier Diffractometer (HRFD), is described. The HRFD combines both high neutron flux at the sample position, ∼107n/cm2/s, provided by the IBR-2 high flux pulsed reactor, and high resolution, very close to 0.001, over a wide range of d-spacings. The paper deals with the basic principles of HRFD, its design, and performance. Examples of structural experiments are also given.