Mesure et correction de surfaces d'onde dans les rayons X

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Off-axis aberration compensation of focusing with spherical mirrors using deformable mirrors

International audienceWe studied the possibility of focusing an ultra-intense laser beam with a spherical mirror instead of a parabolic mirror. To correct the induced wavefront aberrations, we used a deformable mirror in a closed-loop configuration with a Shack–Hartmann Wavefront Sensor (SHWS). We demonstrate in this paper that we were able to correct the aberrations induced by spherical mirrors down to an f-number equal to 3.3

Automatic alignment of a Kirkpatrick-Baez active optic by use of a soft-x-ray Hartmann wavefront sensor

International audienceWe present what we believe to be the first automatic alignment of a synchrotron beamline by the Hartmann technique. Experiments were performed, in the soft-x-ray range (E=3 keV, lambda=0.414 nm), by using a four-actuator Kirkpatrick-Baez (KB) active optic. A system imaging the KB focal spot and a soft-x-ray Hartmann wavefront sensor were used alternatively to control the KB optic. The beam corrected with the help of the imaging system was used to calibrate the wavefront sensor. With both closed loops, we focused the beam into a 6.8 µm×9 µm FWHM focal spot

Synchrotron X-ray footprinting – Mass-spectrometry to probe structure of proteins in interactions

National audienceThe meeting provides an invaluable forum for the synchrotron radiation user community, presenting an important opportunity to obtain the latest information on beamline performance at SOLEIL, to hear about the latest and most exciting results obtained at SOLEIL and to share scientific, technical and practical issues about the synchrotron radiation use

Synchrotron X-ray footprinting – Mass-spectrometry to probe structure of proteins in interactions

National audienceThe meeting provides an invaluable forum for the synchrotron radiation user community, presenting an important opportunity to obtain the latest information on beamline performance at SOLEIL, to hear about the latest and most exciting results obtained at SOLEIL and to share scientific, technical and practical issues about the synchrotron radiation use

Superoxide Production under Soft X-ray Irradiation of Liquid Water

International audienc

A microfluidic dosimetry cell to irradiate solutions with poorly penetrating radiations: a step towards online dosimetry for synchrotron beamlines

International audienceSynchrotron radiation can induce sample damage, whether intended or not. In the case of sensitive samples, such as biological ones, modifications can be significant. To understand and predict the effects due to exposure, it is necessary to know the ionizing radiation dose deposited in the sample. In the case of aqueous samples, deleterious effects are mostly induced by the production of reactive oxygen species via water radiolysis. These species are therefore good indicators of the dose. Here the application of a microfluidic cell specifically optimized for low penetrating soft X-ray radiation is reported. Sodium benzoate was used as a fluorescent dosimeter thanks to its specific detection of hydroxyl radicals, a radiolytic product of water. Measurements at 1.28 keV led to the determination of a hydroxyl production yield, G (HO . ), of 0.025 ± 0.004 µmol J −1 . This result is in agreement with the literature and confirms the high linear energy transfer behavior of soft X-rays. An analysis of the important parameters of the microfluidic dosimetry cell, as well as their influences over dosimetry, is also reported