New cryogenic environment for beamline ID22 at the European Synchrotron Radiation Facility

A compact minicryostat has been well adapted on the hard x-ray microprobe ID22 of the European Synchrotron Radiation Facility. For variable low-temperature investigations, its special technical design provides precise scanning microscopy and allows easy access for multiple detection modes. Based on x-ray excited optical luminescence technique on the micrometer scale, details of the equipment, its temperature calibration, and typical results are described. Data collections from InAs quantum heterostructures support the excellent thermal performance of the novel cryogenic device.     

A high resolution and large solid angle x-ray Raman spectroscopy end-station at the Stanford Synchrotron Radiation Lightsource

We present a new x-ray Raman spectroscopy end-station recently developed, installed, and operated at the Stanford Synchrotron Radiation Lightsource. The end-station is located at wiggler beamline 6-2 equipped with two monochromators-Si(111) and Si(311) as well as collimating and focusing optics. It consists of two multi-crystal Johann type spectrometers arranged on intersecting Rowland circles of 1 m diameter. The first one, positioned at the forward scattering angles (low-q), consists of 40 spherically bent and diced Si(110) crystals with 100 mm diameters providing about 1.9% of 4π sr solid angle of detection. When operated in the (440) order in combination with the Si (311) monochromator, an overall energy resolution of 270 meV is obtained at 6462.20 eV. The second spectrometer, consisting of 14 spherically bent Si(110) crystal analyzers (not diced), is positioned at the backward scattering angles (high-q) enabling the study of non-dipole transitions. The solid angle of this spectrometer is about 0.9% of 4π sr, with a combined energy resolution of 600 meV using the Si (311) monochromator. These features exceed the specifications of currently existing relevant instrumentation, opening new opportunities for the routine application of this photon-in/photon-out hard x-ray technique to emerging research in multidisciplinary scientific fields, such as energy-related sciences, material sciences, physical chemistry, etc.     

A soft x-ray beamline capable of canceling the performance impairment due to power absorbed on its optical elements

We present an entrance slitless beamline design capable of maintaining its very high performance in terms of energy resolution (>10(4)) and spot size (4x4 microm2) at the sample position despite being exposed to more than 2.15 kW of undulator radiation and a maximum power density on the optics of more than 0.9 W/mm2. Ray tracing simulations of this beamline under the worst-case thermal deformations of the optical element surfaces verify that appropriate focusing corrections are able to cancel the deleterious effects of these deformations. One of the necessary conditions for this cancellation is to illuminate the optical elements with a larger solid angle than the undulator's central cone, which contains the usable photons but is considerably smaller than the angular power distribution.     

The μSR setup on the muon beam of the synchrocyclotron at the Konstantinov Institute of Nuclear Physics

The μSR setup for investigating the distribution of magnetic fields in solids using the muon spin rotation (μSR) method is described. The setup is characterized by a high degree of homogeneity of the magnetic field at the site of the sample under investigation, compensation of scattered magnetic fields to a level of ?10^?2 G, and a time resolution of 2.5 ns (the full width at half-maximum). The setup is suitable for μSR measurements on samples in the temperature range of 5–300 K with a precision of ±0.1 K.     

A new experimental setup designed for the investigation of irradiation of nanosystems in the gas phase: a high intensity mass-and-energy selected cluster beam

DIAM (Dispositif d'Irradiation d'Agre?gats Mole?culaires) is a new experimental setup devoted to investigate processes induced by irradiation at the nanoscale. The DIAM apparatus is based on a combination of techniques including a particle beam from high-energy physics, a cluster source from molecular and cluster physics, and mass spectrometry form analytical sciences. In this paper, we will describe the first part of the DIAM apparatus that consists of an ExB double spectrometer connected to a cluster ion source based on a continuous supersonic expansion in the presence of ionizing electrons. This setup produces high intensities of energy-and-mass selected molecular cluster ion beams (1000 s of counts s(-1)). The performance of the instrument will be shown through measurements of 6-8 keV beams of protonated water clusters, (H(2)O)(n)H(+) (n = 0-21) and mixed protonated (or deprotonated) water-pyridine cluster ions: PyrH(+)(H(2)O)(n) (n = 0-15), Pyr(2)H(+) (H(2)O)(n) (n = 0-9), and (Pyr-H)(+) (H(2)O).     

An X-ray Backlighting Technique Based on Using X-Pinch Radiation for Probing the Plasma of Multiwire Imploding Liners at the Angara-5-1 Facility

A method for determining the substance density distribution in the plasma produced by a current-driven implosion of multiwire tungsten liners at the Angara-5-1 facility is described. This method is based on the X-ray probing of plasma with radiation from a point source. As a source of this radiation, an X pinch is used. The time resolution (<2 ns) was determined by the X pinch. The probing of both the liner peripheral and near-axial regions is considered. The plasma-attenuated X-pinch radiation was detected using photographic film and p–i–n diodes in the first and second approach, respectively. The spatial resolutions (over the object) in both cases were determined by the sizes of the X pinch and p–i–n diodes and amounted to 4 and 44 m, respectively. The design of the X-pinch and the dependence of its radiation characteristics (the burst time moment and the radiation-pulse power and duration) on the electric and design parameters of the circuit and load are described. The experimental data on the X-pinch radiation spectrum in the range of photon energies of 1–20 keV and the results of studying the substance-density distribution inside liners during the current-driven implosion at the Angara-5-1 facility are presented.     

A new double-foil soft x-ray array to measure T(e) on the MST reversed field pinch

A soft x-ray (SXR) diagnostic to measure electron temperature on the Madison Symmetric Torus using two complementary methods is presented. Both methods are based on the double-foil technique, which calculates electron temperature via the ratio of SXR bremsstrahlung emission from the plasma in two different energy ranges. The tomographic emissivity method applies the double-foil technique to a tomographic reconstruction of SXR emissivity, creating a two-dimensional map of temperature throughout the plasma. In contrast, the direct brightness method applies the double-foil technique directly to the measured brightness and generates vertical and horizontal radial profiles. Extensive modeling demonstrates advantages and limitations in both techniques. For example, although the emissivity technique provides a two-dimensional mapping of temperature, its reliance on multiple tomographic inversions introduces some artifacts into the results. On the other hand, the more direct brightness technique avoids these artifacts but is only able to provide a radial profile of electron temperature.     

A development of simple analysis model on bumper barrier impact and new IIHS bumper impact using the dynamically equivalent beam approach

This paper presents a simple analysis model for bumper barrier impact and new IIHS (Insurance Institute for Highway Safety) bumper impact instead of a non-linear finite element impact analysis. A dynamically equivalent beam approach was introduced to simplify the non-linear dynamic bumper impact. For a bumper barrier impact, the equivalent curved-beam element was substituted for the bumper beam and the bumper foam. For a new IIHS bumper impact, a modified curved-beam element of bumper barrier impact considering the effect of contoured new IIHS impact barrier was used. The accuracy of this simple analysis model was tested by comparing its results with those of the non-linear finite element analysis. Tested bumper beam types were press type beam and roll forming beam used widely in the current car bumpers. The maximum displacement error between the two models did not exceed 1.95% for a barrier impact and 13.2% for a new IIHS bumper impact. This accuracy is good enough to be used in the early stage of bumper beam design process. This simple analysis model is expected to reduce the car development time and tests cost significantly.