M.N. Yakimenko

Peculiarities of photon transmission through capillary systems

Abstract In this paper a theoretical model for calculation of X-ray photons characteristics under passage through capillary systems is described. The model is based on a numerical solution of a wave equation. It is shown that recently discovered interference effect under multiple reflection of X-rays is a display of wave properties of X-rays. In this report an explanation of the observed phenomenon is given.

Investigation of sensitometric characteristics of X-ray photoemulsions in the spectral range of 15–80 Å

Abstract An investigation of the sensitometric characteristics of X-ray films RAR 2497, SB-2, 101-01 (Kodak), D-7 (Agfa-Gevaert) and UFSh-0 (GNIIKhFP) has been carried out. These films are widely used in scientific research with different types of X-ray sources. The investigation was realized with the aid of a transmission grating spectrograph. An S-60 electron accelerator (P.N. Lebedev Physical Institute) was used as the source of X-ray radiation. The characteristic curves for different wavelengths (within the mentioned range) are presented, as well as the spectral dependences of absolute sensitivity and contrast for the tested films.

Interference phenomenon under focusing of synchrotron radiation by a Kumakhov lens

Abstract Results of experimental and theoretical studies on focusing of synchrotron radiation by means of capillary lenses are presented. For the explanation of the interference effect observed the wave the channeling theory is applied.

Electronic properties of crystalline quartz excited by photons in the 5–25 eV range

Abstract The electronic excitation multiplication process and photoelectron emission in crystalline quartz were investigated and an estimation of the energy gap is presented.

Radiative transitions between anion and cation valence bands in CsBr and CsCl crystals

Abstract For CsBr and CsCl crystals excitation spectra of fast intrinsic luminescence due to radiative transitions between anion and cation valence bands were investigated under pulsed synchrotron radiation (10–30 eV) excitation.

Exciton and electron-hole mechanisms for electronic excitation multiplication in alkaline earth fluoride crystals

Abstract Electronic excitation multiplication processes in alkaline earth fluoride crystals were investigated and the methods for separating exciton and electron-hole multiplication mechanisms are discussed.

Investigations on the S-60 SR source of the Lebedev Physical Institute

Abstract Results of experiments on the luminescence of some crystals and glasses are presented. The materials investigated are promising scintillators for high energy physics experiments. The biological structure of some specimens was determined by measuring the time response of fluorescent probes or of natural fluorophosphors embedded in the examined structures. Capillary structures and results of calibrations of materials sensitive to soft X-ray radiation are also presented.

Intrinsic and impurity cross-luminescence in three-component barium-containing compounds

Abstract Time-resolved luminescence excitation spectra under synchrotron radiation (10–30 eV) excitation for the barium-containing compounds BaLn 2 F 8 (Ln = Y, Tm, Yb), (BaF 2 ) 1- x (NdF 3 ) x ( x = 0.005−0.3) and SrF 2 Ba 2+ (0.1–1%) were investigated. It was shown that BaY 2 F 8 crystals have fast cross-luminescence with an excitation threshold at hv = 19.3 eV and spectral characteristics similar to that of BaF 2 . By introducing in BaF 2 rare-earth elements with unfilled 4f-shells the long luminescence of self-trapped excitons is suppressed, but fast cross-luminescence is suppressed as well. The existence of impurity cross-luminescence in SrF 2 Ba (excitation threshold at about 18.5 eV) was confirmed. Investigations of impurity cross-luminescence give information about the band structure of crystals which do not have intrinsic cross-luminescence.

Determination of the number of fluorescence emitting molecules in heterogeneous biological objects by use of fluorescence decay function and synchrotron pulse excitation

Abstract A way has been suggested to determine the number of fluorescence emitting molecules in heterogenous biological objects. It is based on the measurement of the pre-exponential factor (amplitude) of fluorescence decay function. The method has been illustrated by three series of experiments on the SR beam station of the S-60 synchrotron of the Lebedev Physical Institute.

Investigation of synchrotron-radiation beam turning using a cylindrical surface

AbstractWe report theoretical and experimental investigations of the x-ray properties of concave cylindrical mirrors for the soft x-ray (SX) band. Elements of this type facilitate solutions of many problems in the control of synchtrotron-radiation (SR) beams. These include: operation of SR channels; production of a vertical SR beam; transmission of an SR beam to another horizontal plane (to the second story); effective filtering-out of short-wave radiations. We describe the main features of deflection of SX beams by concave surfaces. The angular and spatial distributions of the radiation intensity at the exit from a cylindrical mirror are analyzed by the tridiagonal method. Experimental results are presented on the rotation of an SR beam through 90° by a cylindrical mirror with a reflecting carbon coating. The efficiency of the SR transfer was investigated in wide range