Siberian Synchrotron Research Articles

Development of a silicon microstrip detector prototype for ultra-fast imaging at a synchrotron radiation beam

A method of imaging of ultra-fast processes, like explosion or fast combustion, at a synchrotron radiation beam is being developed at the Siberian Synchrotron and Teraherz Radiation Center (SSTRC) . Two stations are operating at beam line 0 at the VEPP-3 storage ring and at beam line 8 at the VEPP-4M storage ring. Both stations are equipped with the detector for imaging of explosions DIMEX, based on high pressure ionization chamber, and allowing to record up to 100 one dimensional images with the frame rate of 8 MHz. However the maximum flux that DIMEX can detect is limited as well as spatial resolution and frame rate because of gas technology used. In view of significant increase of SR flux at the VEPP-4M beam line due to the new 9-pole 2 T wiggler, a new detector is being developed for this beam line, based on Si microstrip sensor. The first Si microstrip detector prototype has been mounted with new specially developed front-end ASIC that allows to record data with the rate of 50 MFrames/s. The first measurements with this prototype demonstrated significant improvement of all critical parameters of the detector compared to the gaseous version.

Operation of a silicon microstrip detector prototype for ultra-fast imaging at a synchrotron radiation beam

A method of imaging of ultra-fast processes, like explosions or fast combustion, at a synchrotron radiation beam is being developed at the Siberian Synchrotron and Terahertz Radiation Center (SSTRC). Two stations are equipped with the detector for imaging of explosions, DIMEX, based on high pressure ionization chamber, and allowing to record up to 100 one dimensional images with a frame rate of 8 MHz. However the maximum flux that DIMEX can detect is limited as well as the spatial resolution and the frame rate because of the gas technology used. In view of the significant increase of SR flux at the VEPP-4M beam line due to the new 9-pole 2 T wiggler, a new detector is being developed for this beam line, based on Si microstrip sensor. The first Si microstrip detector prototype has been mounted with a new specially developed front-end ASIC that allows to record data with a rate up to 40 MFrames/s. The first measurements with this prototype demonstrated significant improvement of all critical parameters of the detector compared to the gaseous version. The maximum detected photon rate before saturation is increased to 20000 photons/(channel x bunch) compared to 1500 photons/(channel x bunch). The spatial resolution is improved from 240μm to 130μm (FWHM) and the frame rate is increased by a factor 5.

Searching for Annually Stratified Bottom Sediments in Altai Mountain Lakes by Means of XRF Microanalysis Using Synchrotron Radiation

Bottom sediments from Lake Kucherlinskoe that contain finely-laminated layers are studied using micro-XRF on synchrotron radiation beams from the VEPP-3 storage ring. Samples with visible layers are prepared as solid specimens impregnated with epoxy. The procedure for preparing the samples preserves the original structure and composition of the sediment. Scanning X-ray fluorescence microanalysis of the samples is performed on an experimental setup at the joint usage center of the Institute of Nuclear Physics, Siberian Synchrotron and Terahertz Radiation Center. Scan profiles with increments of 100 and 200 µm are obtained that contain data on the distribution of over 20 rock-forming and microelements. The experimental material is used to confirm the annual nature of the observed layering of sediments, estimate the rate of sedimentation, and construct a lithological and geochemical model of the sedimentation process.

The SRXFA Station on the VEPP-4M Storage Ring

A description is given of the SRXFA synchrotron radiation station on the VEPP-4M storage ring at the Siberian Synchrotron and Terahertz Radiation Center. The station is intended to develop and implement SRXFA technology in the hard X-ray photon (40–120 keV) range. The main parameters of the station are given, along with its layout, its monochromatic system, and its detector. The X-ray fluorescence spectrum obtained at the SRXFA station on the VEPP-4M storage ring at an excitation energy of 112 keV is presented. Results obtained at the station on the minimum detection limits for rare-earth elements are presented.

Constructing Lithological/Geochemical Time Series in the Cross Sections of Bottom Sediments of Lake Karakel Using Data from Micro-XRF Scanning with a Beam of Synchrotron Radiation on the VEPP-3 Storage Ring

Cores of bottom sediments of Lake Karakel (Northern Caucasus) were obtained in 2010 and 2014 to perform geochemical studies for reconstructing the regional paleoclimate of the late Holocene. Solid samples of bottom sediments were scanned via micro-XRF with a step of 1 mm at the shared resource center of the Siberian Synchrotron and Terahertz Radiation Center. The contents of more than 20 elements were determined. The scan profiles are used to construct a single reference section with correction for a sediment layer dated via radiocarbon analysis, and to create a sediment core age–depth model.

Indicators of Oxic and Anoxic Conditions in the System of the Current Sedimentation of Saline Lake Shira (Khakassia), According to High-Resolution SR XRF Data on Bottom Sediments Frozen In Situ

Frozen upper layers of the bottom sediment of Lake Shira are selected using special sampling equipment. Frozen samples and solid samples prepared from the upper layers of a sediment core are examined by means of X-ray fluorescence at the Local and Scanning X-Ray Fluorescence Elemental Analysis Station of the Siberian Synchrotron and Terahertz Radiation Center’s Shared Resource Center. Analytical data on the initial frozen and processed solid samples demonstrate the good repeatability of the results. Quantitative estimates of the sedimentation regimes are obtained, and geochemical indicators of the change in redox conditions are determined from the analysis data. Lithological and geochemical records are synchronized with regional seasonal and annual variations in weather and climate, and with the hydrological regime of the lake for the last 50 years.

Investigations of fast processes by X-ray diffraction methods at the Siberian Synchrotron and Terahertz Radiation Center

A unique instrumentation complex that includes wigglers, X-ray position sensitive detectors, diffractometers, and explosion chambers and enables a 73 ps X-ray diffraction time resolution (exposure time) has been developed at the Siberian Synchrotron and Terahertz Radiation Center, a research collaboration operating at the Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences. A number of techniques have been developed and implemented with which nanosecond-resolution investigations of the nucleation and growth dynamics became possible for the first time for diamond and metal nanoparticles under explosion and shock wave conditions. Studies with millisecond resolution of the structural transformation dynamics of chemical reactions, investigations of the kinetics of self-propagating high-temperature synthesis, and obtaining information on the state of catalysts are also among the new possibilities developed.

Lattices for a 4th-Generation Synchrotron Light Source

Inspired by light source upgrades, such as ESRF-EBS (Extremely Brilliant Source) and APS-U, I present some modern lattices for a medium-sized 4th-generation synchrotron radiation source. They incorporate new elements, such as anti-bend magnets. The composed lattices are optimized using a simple double-objective algorithm. Its goal is to minimize the natural emittance and absolute chromaticities simultaneously. Then, the lattices are analyzed and compared to a version of the ESRF-EBS lattice scaled down in size. The design is performed to meet the needs of the user community of the Siberian Synchrotron and Terahertz Radiation Centre under the umbrella of the Budker Institute of Nuclear Physics.

On the Search and Localization of Platinum-Group Microelements in Samples of the Chromite Horizon in the Bushveld Complex

The search for microinclusions of light platinoids (Ru and Pd) in samples of the Bushveld intrusion complex (South Africa) and corresponding examination are performed by scanning X-ray fluorescence analysis at the SR XRF experimental station with the help of the VEPP-3 storage ring at the Collective-Use Center “Siberian Synchrotron and Terahertz Radiation Center” based at the Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences. The samples are prepared as plane parallel ground plates 2 mm in thickness. First, one-dimensional scanning with a wide beam (1 × 20 mm) of monochromatic radiation with an excitation energy of 20 and 30 keV is performed. Then, the region with higher contents of light platinoids is two-dimensionally scanned with a beam (30 × 45 μm) which is focused with a polycapillary lens. Sample surface mapping enables identification of a few individual particles 50–100 μm in size with a high Pd content. The potential for micro-XAFS investigation of an individual particle is demonstrated.

Mercury in archeological hair samples from Xiongnu burials (Noin‐Ula, Mongolia): SR XRF and CXRM analysis

A technique has been developed for determining mercury content in the concentration range of 1–1000 μg/g in hair samples by X‐ray fluorescence analysis using synchrotron radiation (synchrotron radiation X‐ray fluorescence, Siberian Synchrotron and Terahertz Radiation Center, Budker Institute of Nuclear Physics SB RAS). The mercury content was identified in archeological hair samples from an ancient burial of Xiongnu nobility (Mongolia, mound 22, 1st century BC–1st century AD); the content values were elevated (up to 1100 μg/g) in all the samples (n = 41). An X‐ray microanalysis using polycapillary lenses in a confocal scheme (confocal X‐ray microscopy station) was developed at the Synchrotron radiation X‐ray fluorescence to establish mercury distribution in a cross section of hair shaft with a spatial resolution of 5 μm. The findings of the study make it possible to assume exogenous income of mercury (from the burial environment) to the hair.

Research on fast solid-state chemical reactions at the Siberian Synchrotron and Terahertz Radiation Center

The potent equipment of the shared-use center “Siberian Synchrotron and Terahertz Radiation Center” at Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (BINP SB RAS) enables conduction of time-resolved X-ray diffraction experiments using synchrotron radiation of the VEPP-3/VEPP-4 storage rings. These experiments are performed mostly for institutions of the Siberian Branch of the Russian Academy of Sciences (SB RAS). The experiments yielded novel techniques, which have been implemented for investigation into the dynamics of the nucleation and formation of nanoparticles under explosion and shock wave impact with a nanosecond-scale time resolution (the X-ray exposure time is 73 ps), dynamics of structural transformations in chemical reactions, and kinetics of chemical reactions during gasless combustion (SHS) with a millisecond-scale time resolution, obtaining structural information about the state of catalysts and so on.

The modified experimental X-ray powder diffraction station on the SR beamline no. 2 of VEPP-3 storage ring

Modernization of the experimental station mounted on the beamline No. 2 of VEPP-3 synchrotron radiation electron storage ring at Siberian Synchrotron and Terahertz Radiation Center and intended for X-ray diffraction studies of the structure and phase composition of functional materials with high angular resolution and the possibility of using the effect of resonance scattering has been done. In operating mode the diffractometer of the beamline is equipped with a perfect flat analyzer crystal Ge(111), located in front of the detector. XRD patterns can be obtained in the range of photon energies from 7 keV to 18 keV (or wavelength range ~0.18÷0.07 nm). The angular range of the X-ray registration is limited to 2θ = 140°. The work was performed using a complex VEPP-3/VEPP-4.

Synchrotron Radiation Applications in the Siberian Synchrotron and Terahertz Radiation Center

The Siberian Synchrotron and Terahertz Radiation Center (SSTRC, Budker Institute of Nuclear Physics (INP), Novosibirsk, Russian Federation) is one of the oldest and main Russian centers for synchrotron radiation applications. The center combines research efforts of numerous scientific groups, mostly from institutes and universities of the Novosibirsk Scientific Center (Siberian Branch of the Russian Academy of Sciences) as well as researchers from all over Russia. The center provides access to the most popular synchrotron radiation applications and research techniques including the unique ones in the world. The synchrotron radiation (SR) is produced by VEPP-3 and VEPP-4M storage rings of the INP. Most of the activities of SSTRC is devoted to developing original approaches for synchrotron radiation usage. The report covers activity on synchrotron radiation applications at the Siberian Synchrotron and Terahertz Radiation Center as well as some bright results of recent research.

Manufacturing of Self-bearing Microstructures of the Pseudo-metallic Type for Diffraction Experiments in the Terahertz Range

Specific features of the LIGA-technology methods elaborated at the Siberian Synchrotron and Terahertz Radiation Centre (SSTRC, BINP SB RAS) and fabrication of terahertz filters and optical elements based on high-aspect self-bearing microstructures of the pseudo-metallic type are described. The essence of the method consists in deep X-ray lithographic patterning of an organic glass (PMMA) substrate followed by covering its entire surface with a thin layer of metal (silver). The structures produced are using in the experiments at the Novosibirsk free electron laser.

Multifunctional X-ray Lithography Station at VEPP-3

The multifunctional X-ray lithography “LIGA” station on beamline 0 at the VEPP-3 synchrotron source is part of the shared-use center “Siberian Synchrotron and Terahertz Radiation Center” (SSTRC) in Budker Institute of Nuclear Physics (BINP, Novosibirsk, Russia). The station is intended to exposure of resist layers on substrates of different shape and lateral dimensions of 1 to 10cm. The development of process and re-equipment of the station goes forward, continuously. In this work we consider the current capabilities of the station; examples of microstructures fabricated are presented.

SR-XRFA in Biogeochemical Studies: Elemental Composition of Larch Tissues (Larix cajanderi Mayr.) of the Kuranakh Gold ore Field (Russia, Yakutia)

Technogenic impact on the elemental composition of larch (Larix cajanderi Mayr.) in the Kuranakh Gold ore field (Russia, Yakutia) is considered. Elemental composition of the larch tissues was determined by means of X-ray fluorescence measurements with synchrotron radiation at the “Siberian Synchrotron and Terahertz Radiation Center” based on VEPP-3 of the Budker Institute of Nuclear Physics SB RAS. Comprehensive possibilities of the X-ray fluorescence measurements along with the simple preparation of biological samples, allowed us to carry out valuable biogeochemical studies. New data on the accumulation of macroelements K, Ca, Mn, Fe, biophilic microelements Cu, Zn, chalcophilous Mo, Pb, Ag, As, Sb, Ga, Cd, Tl, rare lithophilous Rb, Sr, Zr, Y, Nb, in the tissues of larch (Larix cajanderi Mayr.) of the natural taiga landscape and the tailing dump in the Kuranakh Gold ore field were obtained. The results allow us to assess both natural and technogenic biogeochemical anomalous aureole of gold mining areas.

Technogenic Fallout of Uranium and Thorium in the Vicinity of Novosibirsk (Russia, West Siberia)

Evaluation of the contribution of definite pollution sources among many others is rather complicated scientific challenge, but its solution may become decisive for the realization of measures aimed at ecological remediation of the territories. Element composition of aerosol particles accumulated during winter in the snow cover of Novosibirsk was determined by means of X-ray fluorescence measurements with synchrotron radiation at the “Siberian Synchrotron and Terahertz Radiation Center” based on VEPP-3 of the Budker Institute of Nuclear Physics SB RAS. Means of ICP-MS and scanning electron microscopy were used additionally. These studies allowed revealing the contribution of separate industrial enterprises into the general technogenic pollution of the megapolis with uranium and thorium.

Application of Synchrotron Radiation for In Situ XRD Investigation of Zirconium Hydrides Formation at Gas-phase Hydrogenation

The zirconium alloy (Zr1%Nb) samples with a micron-thick nickel layer were investigated for hydrogen sorption ability. Hydrogenation was carried out by gas phase method at temperatures of 350, 450 and 550° C. Hydrogen pressure in chamber was 1 atm. Hydrogen sorption curves were obtained on the automated complex Gas Reaction Controller. In situ X-ray diffraction measurements of the process of hydrogen saturation of samples were carried out at the station “Precision diffractometry» at Siberian Synchrotron and Terahertz Radiation Center of the Budker Institute of Nuclear Physics. Hydrogen absorption rate by Zr1%Nb alloy increases by order of magnitude with increasing temperature. The phase transitions significantly affect the rate of hydrogen absorption at constant temperature. Measurements were performed using SR from the VEPP-3 storage ring.

Upgrade of the Detector for Imaging of Explosions

Methods of dynamic imaging of explosions at a synchrotron radiation (SR) beam and small-angle X-ray scattering experiments with exploding samples are being developed in the Siberian Synchrotron Radiation Center (SSRC) at the Budker Institute of Nuclear Physics for more than fifteen years. The detector for imaging of explosions (DIMEX) was developed for these purposes and successfully operating at the beam line 0 at the VEPP-3 storage ring and at the beam line 8 at the VEPP-4M storage ring. The DIMEX is based on gas technology and allow to measure SR flux as a function of position and time with spatial resolution of ∼200 μm (FWHM), maximum frame rate of 2MHz and time resolution of ∼80ns. Maximum value of the SR flux that can be measured by the present detector corresponds to ∼5000 photons/(channel*bunch) (20 keV average energy, channel area 0.1x0.5 mm2, bunch revolution frequency 4MHz). Maximum number of frames that can be stored in the present detector is 32 and the number of channels with 0.1mm width is 512. In order to significantly improve the precision of data obtained by the DIMEX an upgrade of the detector has been started. The electronics of the gaseous version of the detector has been changed such that the new detector is able to operate with frame rate of 8MHz and store data in up to 100 frames. A new ASIC was developed for this purpose called DMXG64A that includes 64 channels with low noise integrator and 100 analogue memory cells in each channel. Input charge can be stored to and read out from analogue cells with maximum frequency 10MHz. This new version of the detector is called the DIMEX-G and is planned to be used at the VEPP-3 storage ring and for SAXS studies at the VEPP-4M storage ring. For imaging of explosions at the beam line 8 at the VEPP-4M storage ring, where SR flux is expected to be about 10-100 times higher than at the VEPP-3, a new detector based on Si micro-strip technology is being developed. Si micro-strip sensors with special design have been manufactured by Hamamatsu Photonics company. Each sensor contains 1024 30mm long strips with 50μm pitch. The sensor thickness is 320μm and it will be positioned at an angle of 1.7 degrees with respect to the SR beam plane in order to get effective Si thickness along the beam close to 10mm. The new detector called DIMEX-Si will have spatial resolution of 50μm (FWHM) and time resolution close to 10ns. The new ASIC is under development for this project that will allow to operate with the frame rate of 50MHz and record maximum charge that corresponds to the flux close to 106 photons/(chan*bunch), i.e. about 100 times higher than with present detector.

EXAFS Study of a Model Flotation System - Xanthate/Zinc Sulphate: Structural Determination of Interaction Forms Existing in Aqueous Solution and Deposition

This work presents first results of an EXAFS study of a model flotation system – the xanthate/zinc sulphate in aqueous solution, initial solutions of zinc sulphate and reference bulk samples. All EXAFS spectra (Zn-K edge) of the samples studied (both in solution and deposition) were recorded at EXAFS station of Siberian Synchrotron Terahertz Radiation Center (SSTRC, Novosibirsk) based on VEPP-3 storage ring. Some differences of local structure of initial solution of zinc sulfate (∼10-2 mol/l) compared to the bulk reference sample were found. The presence of different Zn-O forms were proposed. For the model flotation system - xanthate/zinc sulphate in aqueous solution, the Zn-S forms were predominantly found. The structural determination of interaction forms existing in aqueous solution and deposition were carried out in comparison with the initial bulk and reference samples. All possible structural models were discussed. A preliminary structural analysis has done. Perspectives of the used approach are shown.