The new HMI beamline MAGS an instrument for hard X ray diffraction at BESSY

The Hahn Meitner Institute Berlin is operating the new hard X ray diffraction beamline MAGS at the Berlin synchrotron radiation source BESSY. The beamline is intended to complement the existing neutron instrumentation at the Berlin Neutron Scattering Centre. The new beamline uses a 7 T multipole wiggler to produce photon fluxes in the 1011 1012 photons s 100 mA 0.1 bandwidth range at energies from 4 to 30 keV at the experiment. It has active bendable optics to provide flexible horizontal and vertical focusing and to compensate the large heat load from the wiggler source. The experimental endstation consists of a six circle Huber diffractometer which can be used with an additional polarization analyser and different sample environments. The beamline is intended for single crystal diffraction and resonant magnetic scattering experiments for the study of ordering phenomena, phase transitions and materials scienc

Ultra precise characterization of LCLS hard X ray focusing mirrors by high resolution slope measuring deflectometry

We present recent results on the inspection of a first diffractionlimited hard X ray Kirkpatrick Baez KB mirror pair for the Coherent Xray Imaging CXI instrument at the Linac Coherent Light Source LCLS . The full KB system mirrors and holders was under inspection by use of high resolution slope measuring deflectometry. The tests confirmed that KB mirrors of 350mm aperture length characterized by an outstanding residual figure error of lt;1 nm rms has been realized. This corresponds to the residual figure slope error of about 0.05 amp; 956;rad rms, unprecedented on such long elliptical mirrors. Additional measurements show the clamping of the mirrors to be a critical step for the final shape preserving installation of such outstanding optic

1 m long multilayer-coated deformable piezoelectric bimorph mirror for adjustable focusing of high-energy X-rays

The Diamond Light Source (DLS) beamline I15-1 measures atomic pair distribution functions (PDF) using scattering of 40-80 keV X-rays. A unique focusing element was needed to condense these X-rays from an initial large cross section (11.0 mm H × 4.2 mm V) into a required spot size of FWHM ≈680 μm (H) × 20 μm (V) at a variable position between the sample and the detector. The large numerical aperture is achieved by coating a silicon substrate over 1 m long with three multilayer stripes of Bragg angle 4.2 mrad. One stripe selects X-rays of each energy 40.0, 65.4, and 76.6 keV. Sixteen piezoelectric bimorph actuators attached to the sides of the mirror substrate adjusted the reflecting surface’s shape. Focal spots of vertical width < 15 μm were obtained at three positions over a 0.92 m range, with fast, easy switching from one focal position to another. Minimized root mean square slope errors were close to 0.5 μrad after subtraction of a uniform curvature. Reflectivity curves taken along each stripe showed consistent high peaks with generally small angular variation of peak positions. This is the first application of a 1 m long multilayercoated bimorph mirror at a synchrotron beamline. Data collected with its help on a slice of a lithium ion battery’s cathode are presented

Melting of tantalum at high pressure determined by angle dispersive x-ray diffraction in a double-sided laser-heated diamond-anvil cell

The high pressure and high temperature phase diagram of Ta has been studied in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements up to 52 GPa and 3800 K. The melting was observed at nine different pressures, being the melting temperature in good agreement with previous laser-heated DAC experiments, but in contradiction with several theoretical calculations and previous piston-cylinder apparatus experiments. A small slope for the melting curve of Ta is estimated (dTm/dP = 24 K/GPa at 1 bar) and a possible explanation for this behaviour is given. Finally, a P-V-T equation of states is obtained, being the temperature dependence of the thermal expansion coefficient and the bulk modulus estimated.Comment: 31 pages, 8 figures, to appear in J.Phys.:Cond.Matte

Sustainable polyethylene fabrics with engineered moisture transport for passive cooling

Polyethylene (PE) has emerged recently as a promising polymer for incorporation in wearable textiles owing to its high infrared transparency and tuneable visible opacity, which allows the human body to cool via thermal radiation, potentially saving energy on building refrigeration. Here, we show that single-material PE fabrics may offer a sustainable, high-performance alternative to conventional textiles, extending beyond radiative cooling. PE fabrics exhibit ultra-light weight, low material cost and recyclability. Industrial materials sustainability (Higg) index calculations predict a low environmental footprint for PE fabrics in the production phase. We engineered PE fibres, yarns and fabrics to achieve efficient water wicking and fast-drying performance which, combined with their excellent stain resistance, offer promise in reducing energy and water consumption as well as the environmental footprint of PE textiles in their use phase. Unlike previously explored nanoporous PE materials, the high-performance PE fabrics in this study are made from fibres melt spun and woven on standard equipment used by the textile industry worldwide and do not require any chemical coatings. We further demonstrate that these PE fibres can be dry coloured during fabrication, resulting in dramatic water savings without masking the PE molecular fingerprints scanned during the automated recycling process

High-pressure structural study of the scheelite tungstates CaWO4 and SrWO4

Angle-dispersive x-ray diffraction (ADXRD) and x-ray absorption near edge structure (XANES) measurements have been performed in the AWO4 tungstates CaWO4 and SrWO4 under high pressure up to approximately 20 GPa. Similar phase transitions and phase transition pressures have been observed for both tungstates using the two techniques in the studied pressure range. Both materials are found to undergo a pressure-induced scheelite-to-fergusonite phase transition under sufficiently hydrostatic conditions. Our results are compared to those found previously in the literature and supported by ab initio total energy calculations. From the total energy calculations we have also predicted a second phase transition from the fergusonite structure to a new structure identified as Cmca. Finally, a linear relationship between the charge density in the AO8 polyhedra of ABO4 scheelite-related structures and the bulk modulus is discussed and used to predict the bulk modulus of other materials, like zircon.Comment: 52 pages, 9 figure, 4 table

Association of kidney disease measures with risk of renal function worsening in patients with type 1 diabetes

Background: Albuminuria has been classically considered a marker of kidney damage progression in diabetic patients and it is routinely assessed to monitor kidney function. However, the role of a mild GFR reduction on the development of stage 653 CKD has been less explored in type 1 diabetes mellitus (T1DM) patients. Aim of the present study was to evaluate the prognostic role of kidney disease measures, namely albuminuria and reduced GFR, on the development of stage 653 CKD in a large cohort of patients affected by T1DM. Methods: A total of 4284 patients affected by T1DM followed-up at 76 diabetes centers participating to the Italian Association of Clinical Diabetologists (Associazione Medici Diabetologi, AMD) initiative constitutes the study population. Urinary albumin excretion (ACR) and estimated GFR (eGFR) were retrieved and analyzed. The incidence of stage 653 CKD (eGFR &lt; 60 mL/min/1.73 m2) or eGFR reduction &gt; 30% from baseline was evaluated. Results: The mean estimated GFR was 98 \ub1 17 mL/min/1.73m2 and the proportion of patients with albuminuria was 15.3% (n = 654) at baseline. About 8% (n = 337) of patients developed one of the two renal endpoints during the 4-year follow-up period. Age, albuminuria (micro or macro) and baseline eGFR &lt; 90 ml/min/m2 were independent risk factors for stage 653 CKD and renal function worsening. When compared to patients with eGFR &gt; 90 ml/min/1.73m2 and normoalbuminuria, those with albuminuria at baseline had a 1.69 greater risk of reaching stage 3 CKD, while patients with mild eGFR reduction (i.e. eGFR between 90 and 60 mL/min/1.73 m2) show a 3.81 greater risk that rose to 8.24 for those patients with albuminuria and mild eGFR reduction at baseline. Conclusions: Albuminuria and eGFR reduction represent independent risk factors for incident stage 653 CKD in T1DM patients. The simultaneous occurrence of reduced eGFR and albuminuria have a synergistic effect on renal function worsening

ESRF ID32, SEXAFS and Standing Waves Beamline: An Open Architecture Setup for Surface Studies

The optics of TD32, the SEXAFS and X-Ray Standing Waves (XSW) beamline of ESRF, consists in a main monochromator, a bimorph mirror, a high resolution postmonochromator and a polarization rotator. The experimental setup envisages two instruments: a general purpose UHV chamber fitted with the usual surface preparation and characterization tools and a four circle diffractometer that can host different sample environments (UHV chambers, liquid cells or controlled atmosphere reactors). Various detection schemes including fluorescence detectors, crystal analyzers and a two dimensional gas filled detector complete the beamline instrumentation