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Here, we report on the conceptual design, the hardware realization, and the first experimental results of a novel and compact x-ray polarimeter capable of a single-pulse linear polarization angle detection in the extreme ultraviolet photon energy range. The polarimeter is tested by performing time resolved pump-probe experiments on a Ni80Fe20 Permalloy film at the M-2,M-3 Ni edge at an externally seeded free-electron laser source. Comparison with similar experiments reported in the literature shows the advantages of our approach also in view of future experiments.

X-ray computed micro-tomography (μCT) is one of the most advanced and common non-destructive techniques in the field of medical imaging and material science. It allows recreating virtual models (3D models), without destroying the original objects, by measuring three-dimensional X-ray attenuation coefficient maps of samples on the (sub) micrometer scale. The quality of the images obtained using μCT is strongly dependent on the performance of the associated X-ray detector i.e. to the acquisition of information of the X-ray beam traversing the patient/sample being precise and accurate. Detectors for μCT have to meet the requirements of the specific tomography procedure in which they are going to be used. In general, the key parameters are high spatial resolution, high dynamic range, uniformity of response, high contrast sensitivity, fast acquisition readout and support of high frame rates. At present the detection devices in commercial μCT scanners are dominated by charge-coupled devices (CCD), photodiode arrays, CMOS acquisition circuits and more recently by hybrid pixel detectors. Monolithic CMOS imaging sensors, which offer reduced pixel sizes and low electronic noise, are certainly excellent candidates for μCT and may be used for the development of novel high-resolution imaging applications. The uses of monolithic CMOS based detectors such as the PERCIVAL detector are being recently explored for synchrotron and FEL applications. PERCIVAL was developed to operate in synchrotron and FEL facilities in the soft X-ray regime from 250 eV to 1 keV and it could offer all the aforementioned technical requirements needed in μCT experiments. In order to adapt the system for a typical tomography application, a scintillator is required, to convert incoming X-ray radiation (∼ tens of KeV) into visible light which may be detected with high efficiency. Such a taper-based scintillator was developed and mounted in front of the sensitive area of the PERCIVAL imager. In this presentation we will report the setup of the detector system and preliminary results of first μCTs of reference objects, which were performed in the TomoLab at ELETTRA.

The SOLEIL synchrotron radiation source is regularly operated in special filling modes dedicated to pump–probe experiments. Among others, the low-α mode operation is characterized by shorter pulse duration and represents the natural bridge between 50 ps synchrotron pulses and femtosecond experiments. Here, the capabilities in low-α mode of the experimental set-ups developed at the TEMPO beamline to perform pump–probe experiments with soft X-rays based on photoelectron or photon detection are presented. A 282 kHz repetition-rate femtosecond laser is synchronized with the synchrotron radiation time structure to induce fast electronic and/or magnetic excitations. Detection is performed using a two-dimensional space resolution plus time resolution detector based on microchannel plates equipped with a delay line. Results of time-resolved photoelectron spectroscopy, circular dichroism and magnetic scattering experiments are reported, and their respective advantages and limitations in the framework of high-time-resolution pump–probe experiments compared and discussed. Fil: Silly, Mathieu G.. Synchrotron Soleil; Francia Fil: Ferte, Tom. Synchrotron Soleil; Francia Fil: Tordeux, Marie Agnes. Synchrotron Soleil; Francia Fil: Pierucci, Debora. Synchrotron Soleil; Francia Fil: Beaulieu, Nathan. Synchrotron Soleil; Francia Fil: Chauvet, Christian. Synchrotron Soleil; Francia Fil: Pressacco, Federico. Synchrotron Soleil; Francia Fil: Sirotti, Fausto. Synchrotron Soleil; Francia Fil: Popescu, Horia. Synchrotron Soleil; Francia Fil: Lopez Flores, Victor. Synchrotron Soleil; Francia Fil: Tortarolo, Marina del Carmen. Synchrotron Soleil; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sacchi, Maurizio. Universite de Paris Vi. Institut des Nanosciences de Paris; Francia Fil: Jaouen, Nicolas. Synchrotron Soleil; Francia Fil: Hollander, Philippe. Synchrotron Soleil; Francia Fil: Ricaud, Jean Paul. Synchrotron Soleil; Francia Fil: Bergeard, Nicolas. Synchrotron Soleil; Francia Fil: Boeglin, Christine. Synchrotron Soleil; Francia Fil: Tudu, Bharati. Synchrotron Soleil; Francia Fil: Delaunay, Renaud. Universite de Paris VI; Francia Fil: Luning, Jan. Universite de Paris VI; Francia Fil: Malinowski, Gregory. Synchrotron Soleil; Francia Fil: Hehn, Michel. Synchrotron Soleil; Francia Fil: Baumier, Cedric. Université Paris Sud; Francia Fil: Fortuna, Franck. Université Paris Sud; Francia Fil: Krizmancic, Damjan. Elettra - Synchrotron Light Laboratory; Italia Fil: Stebel, Luigi. Elettra - Synchrotron Light Laboratory; Italia Fil: Sergo, Rudi. Elettra - Synchrotron Light Laboratory; Italia Fil: Cautero, Giuseppe. Elettra - Synchrotron Light Laboratory; Italia

We report here an experimental setup to perform three-pulse pump-probe measurements over a wide wavelength and temperature range. By combining two pump pulses in the visible (650-900 nm) and mid-IR (5-20 $\mu$m) range, with a broadband supercontinuum white-light probe, our apparatus enables both the combined selective excitation of different material degrees of freedom and a full time-dependent reconstruction of the non-equilibrium dielectric function of the sample. We describe here the optical setup, the cryogenic sample environment and the custom-made acquisition electronics capable of referenced single-pulse detection of broadband spectra at the maximum repetition rate of 50 kHz, achieving a sensitivity of the order of 10$^{-4}$ over an integration time of 1 s. We demonstrate the performance of the setup by reporting data on mid-IR pump, optical push and broadband probe in a single-crystal of Bi$_2$Sr$_2$Y$_{0.08}$Ca$_{0.92}$Cu$_2$O$_{8+\delta}$ across the superconducting and pseudogap phases., Comment: 12 pages, 7 figures

FERMI@Elettra is a free electron-laser (FEL)-based user facility that, after two years of commissioning, started preliminary users' dedicated runs in 2011. At variance with other FEL user facilities, FERMI@Elettra has been designed to deliver improved spectral stability and longitudinal coherence. The adopted scheme, which uses an external laser to initiate the FEL process, has been demonstrated to be capable of generating FEL pulses close to the Fourier transform limit. We report on the first instance of FEL wavelength tuning, both in a narrow and in a large spectral range (fine- and coarse-tuning). We also report on two different experiments that have been performed exploiting such FEL tuning. We used fine-tuning to scan across the 1s–4p resonance in He atoms, at ≈23.74 eV (52.2 nm), detecting both UV–visible fluorescence (4p–2s, 400 nm) and EUV fluorescence (4p–1s, 52.2 nm). We used coarse-tuning to scan the M4,5 absorption edge of Ge (∼29.5 eV) in the wavelength region 30–60 nm, measured in transmission geometry with a thermopile positioned on the rear side of a Ge thin foil.

The instrument VOLPE (volume photoemission from solids) is an experimental setup dedicated to high energy photoemission (PE) experiments. The instrument is equipped with an electrostatic hemispherical spectrometer especially designed to analyze high energy electrons (up to 10 keV) with high resolving power. In order to attain an energy resolution of a few tens of millielectron volts, we designed and constructed a dedicated input lens system, high stability power supplies, and a low dark-count detector and readout electronics. The system has been tested and is now operational on the ID16 beamline at European Synchrotron Radiation Facility, where an optical layout has been developed to perform high energy, high resolution PE experiments. First results show an overall energy resolution (electron + photon) of 71+/-7 meV at 5934 eV. The effective attenuation length of the photoelectrons is estimated to be 5+/-0.5 nm at a kinetic energy of 5 keV. (C) 2005 American Institute of Physics.