High-resolution X-ray flash radiography of Ti characteristic lines with a multilayer Kirkpatrick–Baez microscope was developed on the Shenguang-II (SG-II) Update laser facility. The microscope uses an optimized multilayer design of Co/C and W/C stacks to obtain a high reflection efficiency of the Ti characteristic lines while meeting the precise alignment requirement at the Cu Kα line. The alignment method based on dual simulated balls was proposed herein, which simultaneously realizes an accurate indication of the center field of view and the backlighter position. The optical design, multilayer coatings, and alignment method of the microscope and the experimental result of Ti flash radiography of the Au-coned CH shell target on the SG-II Update are described.

The I13 transmission X-ray microscope at Diamond Light Source (DLS) has been designed to cover a broad range of energies and field of views. The beamline operates on an undulator source, and a multilayer monochromator can be used to work at a larger bandwidth to enable faster acquisitions. The experimental design includes large working distances for the optics to allow installing in situ sample environments. This paper presents the current state of the experimental system and shows some of the latest results.

We present a deterministic approach to the ptychographic retrieval of the wave at the exit surface of a specimen of condensed matter illuminated by X-rays. The method is based on the solution of an overdetermined set of linear equations, and is robust to measurement noise. The set of linear equations is efficiently solved using the conjugate gradient least-squares method implemented using fast Fourier transforms. The method is demonstrated using a data set obtained from a gold–chromium nanostructured test object. It is shown that the transmission function retrieved by this linear method is quantitatively comparable with established methods of ptychography, with a large decrease in computational time, and is thus a good candidate for real-time reconstruction.

The recent developments of phase-contrast synchrotron imaging techniques have been of great interest for paleontologists, providing three-dimensional (3D) tomographic images of anatomical structures, thereby leading to new paleobiological insights and the discovery of new species. However, until now, it has not been used on features smaller than 5–7 μm voxel size in fossil bones. Because much information is contained within the 3D histological architecture of bone, including an ontogenetic record, crucial for understanding the paleobiology of fossil species, the application of phase-contrast synchrotron tomography to bone at higher resolutions is potentially of great interest. Here we use this technique to provide new 3D insights into the submicron-scale histology of fossil and recent bones, based on the development of new pink-beam configurations, data acquisition strategies, and improved processing tools. Not only do the scans reveal by nondestructive means all of the major features of the histology at a resolution comparable to that of optical microscopy, they provide 3D information that cannot be obtained by any other method.

In pediatric radiology, radiological protection isof vital importance due to the great radio-sensitivity of body tissuesin childhood, which can come to present stochastic effects as childrenhave a longer life expectancy. The objective of this research isto establish diagnostic reference levels in chest exam pediatricpatients. The study, carried out in one of the largest pediatriccenters of the city of Medellin, the capital of the Department ofAntioquia, consisted of the calculation of the Entrance Skin Dose(ESD) for a sample of 814 chest radiographic studies in the anteroposterior(AP) and left lateral (L LAT) projections, and it was compared withthe doses obtained with the computational program PCXMC 2.0. Forthe estimate of the Entrance Skin Dose, data were collected from theexams, including the size of the radiation field, mAs and kVp. TheESD in chest exams for 5-year-old children was the only one thatexceeded the international reference levels, giving evidence ofthe need to optimize the techniques used in this type of study inthe institution under evaluation.

To diagnose the implosion of a laser-driven-fusion target such as the symmetry, the hydrodynamic instability at the interface, a high-resolution, large field-of-view kilo-electron-volt X-ray imaging is required. A Kirkpatrick-Baez (K-B) microscope is commonly used, but its field of view is limited to a few hundred microns as the resolution decreases rapidly with the increase of the field of view. A higher resolution could be realized by using a Fresnel zone plate (FZP) for imaging. Presented in this work is a numerical study on the imaging properties of an FZP at Ti-Kα wavelength of 0.275 nm, and a comparison to a K-B imager. It is found that the FZP can realize not only a resolution better than 1 µm, but also a field-of-view larger than 20 mm when the FZP is illuminated by X-rays of spectral bandwidth less than 1.75%. These results indicate the feasibility of applying the FZP in high-resolution, large field-of-view X-ray imaging.

A detector that looks promising for advanced imaging modalities—such as X-ray absorption contrast imaging, X-ray fluorescence imaging, and diffraction-enhanced imaging—is the controlled-drift detector (CDD). The CDD is a novel two-dimensional X-ray imager with energy resolving capability of spectroscopic quality. It is built on a fully depleted silicon wafer and features fast readout while being operated at or near room temperature. The use of CDDs in the aforementioned applications allows translating these techniques from synchrotron-based experiments to laboratory-size experiments using polychromatic X-ray generators. We have built a dedicated and versatile detection module based on a 36 mm2 CDD chip featuring pixels of 180 × 180 μm2, and we evaluated the system performance in different X-ray imaging applications both with synchrotron-based experiments and in the laboratory environment.

We describe here the present status of the Advanced Laser Light Source (ALLS) facility, a state-of-the-art multi-beam Ti:sapphire laser system presently under construction in Canada. ALLS is a national user facility to be commissioned in 2005 at the INRS campus near Montreal. The 25 fs ALLS multi-beam laser system has three components, each with different repetition rate and output energy. These multiple laser beams will be used to generate a “rainbow” of femtosecond pulses from the far infrared to hard X-rays, which can be combined to perform unique experiments, such as dynamic molecular imaging. In this paper, we describe two examples of experiments that are planned by our group with the ALLS facility. The first is the highly efficient generation of high-order harmonics using ablation medium. We demonstrate the generation of up to the 53rd harmonics (λ = 15 nm) of a Ti:sapphire laser pulse (150 fs, 10 mJ), using pre-pulse (210 ps, 24 mJ) produced boron ablation as the nonlinear medium. The second example is the demonstration of in-line phase-contrast imaging with an ultrafast (300 fs) laser-based hard X-ray source (Mo K-α line). Images of biological samples have shown great enhancement of contrast due to this technique, distinguishing details that are barely observable or even undetectable in absorption images.

Imploding indirect-drive double shell targets may provide an alternative, non-cryogenic path to ignition at the National Ignition Facility (NIF). Experiments are being pursued at OMEGA to understand the hydrodynamics of these implosions and the possibility of scaling it to the NIF design. We have used 40 beams from the OMEGA laser to directly drive the capsules, and we have used the remaining 20 beams to backlight the imploding shells from two different directions at multiple times. We will review the recent experiments to measure the hydrodynamics of the targets using two-view X-ray radiography of the capsules. We will present data on measured yields from the targets. We will present a measured time history of the hydrodynamics of the implosion. Experiments were pursued using direct drive in which the M-band effect (experienced in the indirect drive experiments) could be eliminated or controlled. It was learned in the direct drive experiments that the best performing capsules were those that had a thin outer layer of gold. This effectively causes M-band pre-heat effects giving implosion hydrodynamics and performance closer to the indirect drive case. We will review the methods used to radiograph the targets and the techniques used to extract useful information to compare with calculations. The effect of imperfections in the target construction will be shown to be minimal during the initial stage of implosion. The yields from the targets were observed to be uniformly low compared to indirect-drive.

Ray-tracing simulations of an optical X-ray system based on a spherically bent crystal operating in Bragg configuration for monochromatic projection imaging of thin samples are presented, obtained using a code developed for that purpose. The code is particularly suited for characterizing experimental arrangements routinely used with laser-produced plasma X-ray sources. In particular, the spatial resolution of the imaging system was investigated and a careful study of the complex pattern of the X-ray backlighting beam was performed.

New easy spectrally tunable backlighting schemes based on a spherically bent crystal are considered. Contrary to traditional backlighting scheme, in which the investigated objects should be placed between the backlighter and the crystal, for the considered schemes an object is placed downstream of the crystal, before the tangential or after the sagittal focus and an image of the object is recorded at the distance from the object corresponding to the needed magnification. The magnification is defined by the ratio of the distances from the sagittal focus to the detector and from the object to the sagittal focus. A ray-tracing modeling and experimental images of test meshes, obtained at incidence angles of the backlighter radiation of 10° and 22°, are presented. It is demonstrated that a simple linear transformation of the obtained astigmatic images allows reconstructing them as a stigmatic with an accuracy of 5–15%. For the spectral range around 9 Å a spatial resolution about 10 μm in a field of view of some square millimeters is achieved experimentally and confirmed by ray-tracing simulations.