Qingguo Yang

X-ray backlighting of imploding aluminium liners on PTS facility

The x-ray backlighting systems, including a 1.865 keV (Si Heα line) spherically bent crystal imaging system and an ∼8.3 keV (Cu Heα line) point-projection imaging system, newly fielded on the Primary Test Stand facility are introduced and its preliminary experimental results in radiography of the aluminium (Al) liners with seeded sinusoidal perturbations are presented. The x-ray backlighter source is created using a 1 TW, 1 kJ Nd: glass high power laser, kilo-joule laser system, recently constructed at China Academy of Engineering Physics. The ablation melt and instability of the imploding Al liner outer edge under the driving current of ∼7.5 MA are successfully observed using these two backlighting systems, respectively.

Graphical method for analyzing wide-angle x-ray diffraction

Wide-angle X-ray diffraction on large-scale laser facility is a well-established experimental method, which is used to study the shock response of single crystal materials by recording X-rays diffracted from numerous lattice planes. We present a three-dimensional graphical method for extracting physical understanding from the raw diffraction data in shocked experiments. This method advances beyond the previous iterative process by turning abstract diffraction theories in shock physics into mathematic issues, providing three-dimensional visualization and quick extraction of data characteristics. The capability and versatility of the method are exhibited by identifying lattice planes for single crystal samples with different orientations and quantitatively measuring the lattice compression and rotation under dynamic loading.

PPPS-2013: Optical and x-ray diagnostics time-resolved K-shell line spectra measu rement of the imploding al wire array

Summary form only given. A device that integrates a Johann-type spectrometer with the x-ray PIN diodes, positioned accurately on the rowland circle of the cylindrical bent crystal with different Bragg angles to aim at different spectral lines, has been developed for measuring th e time-resolved K-shell line emissions of the imploding Al wire array. Four typical channels respectively keyed to the Al ion hydrogen-like (H_α, 0.7171 nm and H_β, 0.6052 nm) and helium-like (He_α, 0.7757 nm and H_β, 0.6634 nm) resonance lines are designed and the signal ratios of the H_α line to the He_α line has been used to retrieve the time-dependent electron temperature. The designing principle of the spectrometer is described and the preliminary experimental results on the YANG and PTS accelerator are presented and analyzed.

Research on a logarithmically bent Laue crystal analyzer for X-ray monochromatic backlight imaging

A new logarithmically bent Laue imaging crystal analyzer (LBLICA) was proposed to obtain the monochromatic image of plasmas and exhibited a great potential for application in the Inertial Confinement Fusion experiment over a large field of view (FOV) and with a high spatial resolution. The imaging geometry of the LBLICA has been discussed. According to the Bragg condition and the equation of the logarithmic spiral, the key image parameters of the crystal analyzer, including the system magnification, the spatial resolution, and the FOV, have been analyzed theoretically. An experiment has been performed with a Cu target X-ray tube as a backlighter to backlight a mesh grid consisting of 50-μm Cu wires, and the monochromatic image of the grid has been obtained with a spatial resolution of approximately 30 μm.

Transient x-ray diffraction to measure the dynamic response of shocked lithium fluoride single crystal

Transient x-ray diffraction, also called time-resolved x-ray diffraction and dynamic x-ray diffraction, is one novel diagnostic technique for probing shocked solids. It can provide direct information about microscopic mechanisms governing shock-induced deformation and structural changes at atomistic scales with nanosecond and picoseconds resolution, and lately, it has become possible to measure the structure of transients with sub-picoseconds and sub–Angstrom resolution with the development of ultrafast lasers which can produce femtosecond electron and x-ray pulses in the form of characteristics emission lines as well as x-ray continua in the keV range. In this paper, we detect and measure directly the dynamic response of lithium fluoride single crystal shocked compressed by laser irradiation in SHENGUANG II. In our experiments, high-intensity lasers irradiated a thin Cu foil to generate helium-like rays as x-ray source. Film (IP--image plate) recorded x rays diffracted from multiple lattice planes both perpendicular and oblique angles to the shock loading direction [100]. We gained the diffraction signals of the lattice planes (200) shocked and unshocked, what’s more, other lattices (113), (1-13). The positions of the diffraction lines associated with the (200) lattice plane indicated compression of the lattice along [100] direction by 13%. In the experiment, a large-angle detector consists of two films-one rectangular in shape,one triangular in shape that are positioned to record x rays diffracted from a shocked single crystal nearly within a full π steradian. The experiment shows that transient x-ray diffraction can diagnose the dynamical response of solid with higher resolution.

Application of focusing x-ray spectrograph with spatial resolution and uniform dispersion in Z-pinch plasmas measurement

Application of focusing x-ray spectrograph with spatial resolution and uniform dispersion in measurement of the imploding Al wire array z-pinch plasma is reported. Uniform dispersion (i.e., the linear dispersion is a constant, or in other words, the x-rays are dispersed on the detector with uniform spacing for every wavelength) is realized by bending the crystal of a spectrograph into a special shape. Since the spatial coordinate of the spectrum obtained by this spectrograph varies linearly with x-ray wavelength, it is very convenient for identification and processing of the experimental spectrum. The experimental results show that this spectrograph has high luminosity, high spectral and spatial resolution and is very suitable for the routine spectrum measurement on the Z-pinch facility or other high-energy-density-physics (HEDP) facilities.