Fast, multi-band photon detectors based on quantum well devices for beam-monitoring in new generation light sources

In order to monitor the photon-beam position for both diagnostics and calibration purposes, we have investigated the possibility to use InGaAs/InAlAs Quantum Well (QW) devices as position-sensitive photon detectors for Free-Electron Laser (FEL) or Synchrotron Radiation (SR). Owing to their direct, low-energy band gap and high electron mobility, such QW devices may be used also at Room Temperature (RT) as fast multi-band sensors for photons ranging from visible light to hard X-rays. Moreover, internal charge-amplification mechanism can be applied for very low signal levels, while the high carrier mobility allows the design of very fast photon detectors with sub-nanosecond response times. Segmented QW sensors have been preliminary tested with 100-fs-wide 400 nm laser pulses and X-ray SR. The reported results indicate that these devices respond with 100 ps rise-times to such ultra-fast laser pulses. Besides, linear scan on the back-pixelated device has shown that these detectors are sensitive to the position of each ultrashort beam bunch

temporary implementation and testing of a confocal sr μxrf system for bone analysis at the x ray fluorescence beamline at elettra

Abstract The confocal μ XRF spectrometer of Atominstitut (ATI) was transported and set up at the X-ray Fluorescence beamline at Elettra - Sincrotrone Trieste. It was successfully adjusted to the incoming beam (9.2 keV). Test measurements on a free-standing Cu wire were performed to determine the size of the focused micro-beam (non-confocal mode, 56 × 35 μ m 2 ) and the size of the confocal volume (confocal mode, 41 × 24 × 34 μ m 2 ) for the Cu–K α emission. In order to test the setup's capabilities, two areas on different human bone samples were measured in confocal scanning mode. For one of the samples the comparison with a previous μ XRF measurement, obtained with a low power X-ray tube in the lab, is presented

A multipurpose experimental facility for advanced X-ray Spectrometry applications

Ponencia presentada en la European Conference on X-Ray Spectrometry (EXRS). 2014Motivation, Ultra High Vacuum Chamber (UHVC) project: To support/enhance the training of scientists/engineers from developing countries in the operation of synchrotron radiation instrumentation; To provide beam time access for R&D projects and hands-on training in SR-XRS based techniques; To promote networking and knowledge sharing; To increase the quality and the competitiveness of the developing countries to apply beam time proposals at SR facilities; To contribute in the further development of XRS techniques in applications with socioeconomicalrelevance (characterization of energy storage/conversion materials, environmental, biological and biomedical applications)Fil: Leani, Juan José. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Leani, Juan José. Nuclear Science and Instrumentation Laboratory, IAEA Laboratories; Austria.Física Atómica, Molecular y Química (física de átomos y moléculas incluyendo colisión, interacción con radiación, resonancia magnética, Moessbauer Efecto.

Bidimensional focusing of x rays by refraction in an edge

10.1364/OL.39.001250Optics Letters3951250-1253OPLE

On the use of clessidra prism arrays in long-focal-length X-ray focusing

Clessidra (hour-glass) X-ray lenses have an overall shape of an old hour glass, in which two opposing larger triangular prisms are formed of smaller identical prisms or prism-like objects. In these lenses, absorbing and otherwise optically inactive material was removed with a material-removal strategy similar to that used by Fresnel in the lighthouse lens construction. It is verified that when the single prism rows are incoherently illuminated they can be operated as independent micro-lenses with coinciding image positions for efficient X-ray beam concentration. Experimental data for the line width and the refraction efficiency in one-dimensional focusing are consistent with the expectations. Imperfections in the structures produced by state-of-the-art deep X-ray lithography directed only 35% of the incident intensity away from the image and widened it by just 10% to 125 m. An array of micro-lenses with easily feasible prism sizes is proposed as an efficient retrofit for the refocusing optics in an existing beamline, where it would provide seven-fold flux enhancement

Surface temperature and distortion of optical elements exposed to high power synchrotron radiation beams (invited)

Mirrors made of various materials have been investigated under surface power densities of approximately 1–2 W/mm2 emitted by a powerful hybrid wiggler installed in the 5.3‐GeV DORIS storage ring. Thermal inhomogeneities and deformations at surfaces with a height resolution of 50 nm have been determined quantitatively. The only material withstanding these power levels without a significant deformation is SiC. Conventional cooling geometries are found to be useless for a reduction of the surface distortion

Diffraction of partially coherent X-ray waves by Clessidra lenses

When small triangular prisms are arranged in arrays which have an overall appearance like an hourglass (in Italian: clessidra) they can focus X-rays owing to a combined action of diffraction and refraction. From the optical point of view these objects can be regarded as a Fresnel variant of concave transmission lenses. Consequently they can provide larger apertures than purely refractive lenses. However, one has to recognize that clessidra lenses will strongly diffract as the lens structure is periodic in the direction perpendicular to the incident beam. In experiments the diffraction is reduced because it is difficult to illuminate the large apertures with a full spatially coherent wavefront. So the illumination is at best partially coherent. In order to interpret available experimental data for this condition, diffraction theory has been applied appropriately to the clessidra structure, taking into account the limited spatial coherence. The agreement between the theoretical simulations and experimental data is very good, keeping the lens properties at their projected values and allowing for only two free model parameters. The first is the lateral spatial coherence; the second is a lens defect, a rounding of all edges and tips in the structure. Both values obtained from the simulations have been found to be in agreement with expectations