N.I. Chkhalo

Structural Changes Study of Co/C and Ni/C Multilayers upon Annealing

A detailed study of structural changes occurring in films and on boundaries in multilayers upon annealing with EXAFS, WAXS, and SAXS methods was performed. The optimum temperature of annealing for the Ni/C and Co/C multilayers obtained by the pulsed laser evaporation method was found.

Study of the inner structure of Co/C and Ni/C multilayers prepared by pulsed laser evaporation method

In the present work we have used the EXAFS and SAXS methods to study the inner structure of “classical” Co/C and Ni/C multilayers. This enabled us to study in detail the structure of a multilayer as a function of the thickness of a metal layer within the multilayer. On the basis of these data a model for multilayer growth produced with pulsed laser evaporation technology is proposed.

Fabrication and performance characteristics of a NiC multilayer grating for hard X-rays

Abstract We have fabricated and tested a lamella multilayer grating for the hard X-ray range with a grating period of 0.97 μm and a Ni C multilayer period of 4.0 nm. To obtain large size gratings the fabrication process included holographic lithography and ion-beam etching. The reflectivity measurements obtained using a triple-axis diffractometer have shown that the diffraction efficiency and the relative intensities of the diffracted orders strongly depend on the incident angle. A very encouraging result is the possibility to direct practically all diffracted energy to any one first order with total suppression of the other orders.

X-ray performance of multilayer gratings: recent advances at SSRC

Abstract In this paper we present the main results at the fabrication, theoretical and experimental studies of X-ray multilayer gratings. The multilayer grating reflectivity measurements in both hard and soft X-rays were performed. The features observed in these experimental data are identified and interpreted by means of numerical simulation method of eigenvectors. The effects of diffuse X-ray scattering from Ni/C multilayer and Ni/C multilayer grating have been investigated. Novel aspects of polychromatic optics based on the application of the multilayer grating in hard X-rays are discussed.

The station for detector calibration in the soft X-ray range at the VEPP-2M storage ring

Abstract The experimental station for detector calibration with synchrotron radiation (SR) in the photon energy range of 0.1–1 keV has been designed and constructed at the storage ring VEPP-2M. SR from a positron beam is extracted from a bending magnet of the storage ring and monochromatized by a multilayer mirror. The first calibration procedures are to use the good calculability of the SR photon flux and the measured parameters of the multilayer monochromator when the calibration is performed in a monochromatic beam, or the reconstruction of a detector spectral sensitivity from detector signals measured in “white” SR beam through a set of calibrated absorbing filters and at different positron energies. A description of the station, the estimations of the calibration uncertainties and preliminary results of the monochromator testing are presented.

Multilayer TiBe interference structures for ultrasoft X-ray radiation prepared by pulsed laser sputtering

Abstract This paper is concerned with the properties of multilayer TiBe interference structures in the ultrasoft X-ray region. The structures were prepared by pulsed laser sputtering with a radiation power density at the target Q= 0.2−1 GW/cm2. It is shown that the angular dependences of the reflection coefficients measured at wavelengths λ = 114 A ( Be K α ) and λ = 1.54 A ( Cu K α ) are described well by the theoretical dependences calculated using the atomic scattering factors from ref. [2]. The value of the reflection coefficient reaches 40% at λ = 114 A .

Reflectometer for precision tests of optical components in the ultrasoft X-ray range

Abstract The design of a reflectometer for testing optical components within the range of 0.7–120 nm is described. The reflectometer covers all scanning regimes with a minimum step in θ of 9 angular seconds. The specimen can be moved across the X-ray beam within the limits of ±7.5 cm. The design of the apparatus envisages keeping the position of goniometer zeros after vacuum pumping. The reflectometer is designed for the study of diffraction gratings, and multilayer and grazing incident X-ray mirrors.

The application of the X-ray standing wave method to study NiC layered structures obtained by laser-assisted deposition

Abstract The X-ray standing wave method using fluorescence yield mode was applied to study the profile of the component-by-component distribution between Ni and C layers in Ni C layered structures produced by laser-assisted deposition. The method of recurrent relationships was used to calculate the standing wave electric field profile, and to reconstruct the Ni deep distribution. Best fitting was obtained if the intermixing thickness was equal to 3–4 A.

High resolution instruments based on X-ray multilayer gratings

Abstract New possibilities in the development of spectral instruments with high resolution and efficiency are opened up by the X-ray multilayer gratings. The main advantage of such gratings in the range of the soft X-ray radiation is their greater operating angles and high reflection coefficients. The high spectral resolution is provided by the large number of operating grooves with the same function as that for the conventional grating. In practice, for the multilayer grating there is no problem of higher orders of diffraction and it is not so sensitive for the surface contamination. In the work presented here there are calculation and experimental data on the diffraction efficiency of a number of gratings for various spectral lines. The scheme of a four-channel soft X-ray spectrometer with the resolution of Λ/δΛ ∼ 1000 is proposed. The spectral characteristics of W/Si multilayer gratings are given in comparison with the crystals and conventional grazing incident gratings.