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X-ray optics with good focusing ability and high spectral resolution are required in X-ray spectroscopy for the diagnosis of high temperature and density plasmas. In our study, a novel X-ray spectrometer is developed to provide the ability to record spectra with excellent focusing performance and high energy resolution. It is accomplished by using a continuously conical crystal (CCC) that is formed by circles with different curvatures. In this paper, we present the foundational work of the design and development of continuously conical crystal spectrometer (CCCS) along with initial results obtained with a titanium (Ti) target as the object source. First, the spectrometer based on such a continuously conical crystal is used to measure X-ray spectra on Ti target X-ray Tube device. The spectral resolution (λ/Δλ) is around 615 with the source size of 1 mm. Then, we test the capability of the spectrometer on Xingguang-III Laser Facility with Ti target. He-like and Li-like Ti lines are recorded based on which the spectrometer performance is evaluated. The experiment result shows that the spectrometer provides a high spectral resolving power up to 1000, while acquiring a one-dimensional image of the source. [ABSTRACT FROM AUTHOR]

We derive an analytical propagation expression of the finite energy Airy-Hermite-Gaussian beam propagating in a uniaxial crystal orthogonal to the optical axis, and calculate numerical examples to investigate the influences of the propagation distance and the ratio of the extraordinary refractive index to the ordinary refractive index on the beam profile. In addition, we also examine the intensity distribution of the beam propagating in the uniaxial crystals at different observation sections. Our research shows that the initial beam profile of the beam remains nearly invariant for a short propagation distance in the crystal. However, as propagation distance continues to increase, the beam width will gradually enlarge, where the diffusion velocities of the beam in theXandYdirections are different. Moreover, both the ratio of the extraordinary refractive index to the ordinary refractive index and the Hermite order number also strongly affect the beam profile in a uniaxial crystal. Our work may find some potential applications in optical trapping and nonlinear optics involving in the special beam profile. [ABSTRACT FROM AUTHOR]

The single-electrode readout method has been applied to a coplanar grid (CPG) array CdZnTe detector in order to halve the number of preamplifiers previously needed and to facilitate imaging applications of CPG detectors. A method of predetermining the width of the optimum collecting electrodes has also been proposed, using the calculated optimum relative gain factor G. Meanwhile, a detailed process for calculating the charge induction efficiency (CIE) is presented. To simplify the calculation process, the computational formula of the CIE was deduced through the integration of the weighting potential. For performance evaluation, a 2 × 2 CPG-array CdZnTe detector was elaborately designed and tested with 137Cs at 662 keV. Experimental results showed the capability of using the CPG-array CdZnTe detector with single collecting electrode readout for γ-ray imaging applications, with the same complexity of associated readout electronics as that of the pixelated CdZnTe detectors. [ABSTRACT FROM AUTHOR]

We have proposed a vertically aligned fast response liquid crystal display (LCD) with three-electrode driving (FIS-VA-3T LCD). Both fringe and in-plane electric fields are used to obtain a strong horizontal electric field causing a high transmittance of the bright state. The normalised transmittance of the FIS-VA-3T cell is 12% higher than that of the previous vertically aligned liquid crystal cell with three-electrode driving (VA-3T). During the turn-off process, a trigger pulse is applied on the top electrode to compel the LC molecules vertically aligned rapidly to show the dark state. The turn-off is very fast (∼0.25 ms); 10 times as fast as that given by the vertical alignment liquid crystal cell (FIS-VA) driven by fringe and in-plane electric fields (∼2.5 ms). Such a fast response and high transmittance device is promising for colour sequential displays and other applications. [ABSTRACT FROM PUBLISHER]

Abstract: It has been observed that pixellated CdZnTe detectors fabricated from crystals experience an extending of space charge region in the polarized state when exposed to a high flux of x-rays and a low flux of x-rays. In this case, in some areas of the CZT detector polarization occurs without high incident flux. Results from these studies reveal that at very high photon flux rates, a space charge region with high density develops and extends, consistent with the accumulation of positive space charge due to the trapping of free-carrier holes created by the x-ray irradiation. The extending of space charge region observed without high x-ray has a direct influence on the irradiation hardness and charge collection efficiency of the devices. [Copyright &y& Elsevier]

We developed a focusing imager with a toroidally bent crystal imager. The imager can be used in X-ray imaging of laser fusion experiments. This article discusses the focusing properties of toroidally bent crystal in Bragg geometry. Simulations of spatial resolution for toroidally bent crystals with different conditions including source size and detector position were done using the ray-tracing method. The applicable conditions for optimized two-dimensional (2D) imaging of X-ray source are proposed. Toroidally bent crystal of mica with curvature radius 290 mm in the meridional plane and 190 mm in the sagittal plane is used as imaging element in the experiments. The high-quality visible 2D X-ray image was obtained with the imaging plate due to the high collection efficiency of the bent crystal imaging system. It is demonstrated that the toroidally bent mica crystal could be used in X-ray imaging. By analyzing the image information of the sagittal direction, we find out that the toroidal crystal imager has spatial resolution about 34 μm. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 226-232, 2012 [ABSTRACT FROM AUTHOR]

Abstract: A novel X-ray backlight imaging system has been developed to obtain diagnostic information about implosion targets, wire-array Z-pinch implosions and ablative Rayleigh–Taylor instability. The key component of the imaging system is the spherically bent quartz (1010) crystal with a curvature radius of 143mm. The imaging system is capable of the two-dimensional, spatially resolved, monochromatic backlight imaging. A monochromatic X-ray backlight imaging experiment using the imaging system was performed for the first time on the “Yang” accelerator at the Chinese Academy of Engineering Physics. The plasma from implosion of aluminium wire arrays was used as the backlighting source. The X-ray film obtained the two-dimensional backlight mesh imaging of He-like aluminium ions. The experimental results show that the X-ray backlight imaging system provides an approximate 75μm spatial resolution at a 9mm×20mm field of view. The backlight imaging system is adequate for monochromatic X-ray backlighting imaging diagnosis on the “Yang” accelerator. [Copyright &y& Elsevier]

A dual-channel, focusing x-ray spectrograph with uniform dispersion (i.e., the linear dispersion of this spectrograph is a constant) is described for measuring the x-ray spectra emission from the hot, dense Al Z pinch plasmas. The spectrograph uses double uniform-dispersed crystals (e.g., a Quartz 1010 crystal and a Mica 002 crystal) as dispersion elements and a double-film box as detector to achieve the simultaneous recording of the time integrated spectrum covering a wide spectral range of ∼5-9 Å. Since this spectrograph disperse the x-rays on the detector plane with uniform spacing for every wavelength, it needs not the calibration of the wavelength with spatial coordinate, thereby own the advantages of easiness and veracity for spectra identification. The design of this spectrograph and the example of experiment on the 'Yang' accelerator are presented. [ABSTRACT FROM AUTHOR]

An in-chamber, mini x-ray imaging instrument employs a pinhole and a logarithmic spiral crystal has been developed for obtaining K-shell line images of the imploding aluminum wire array on the 'Yang' accelerator. The logarithmic spiral crystal acts as a monochromator and a non-dispersive mirror that reflects the pinhole image to a x-ray film detector with a very narrow photon energy bandwidth (<1 eV, mainly determined by the width of rocking curve of the crystal). Two imaging configurations with the use of Quartz ([formula]) crystal and Mica (002) crystal are designed, respectively, to image the Al Lyα2 line (1727.7 eV) emission and Al Heα intercombination line (1588.3 eV) emission. The primary experimental data corresponding to these two configurations are presented and discussed. [ABSTRACT FROM AUTHOR]

Based on the Bragg law and imaging principle of bent crystal, the imaging properties of the monochromic backlighting system with a toroidally bent crystal were studied via ray-tracing simulations and experiments. Comparison experiments with both toroidally and spherically bent crystals using a Cr line as the backlighter were performed, showing that using toroidally bent crystal, a 2D image with the same magnifications in meridional and sagittal directions can be obtained with higher spatial resolution. Experiments with laser-produced plasmas using Mica crystal were carried out on the Shenguang II laser facility. Five laser beams were focused onto a Ti planar target producing a line at 4.75 keV as the backlighter and an image of a metal grid with size of 200 μm  ×  200 μm was recorded with an x-ray image plate. A spatial resolution of 40 μm was demonstrated with a magnification of 3 due to the restriction of the target chamber size. 10 μm spatial resolution might be possible if the detector can be located outside the chamber to enlarge the magnification. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Massive efforts have been made to investigate the characteristics of the CdZnTe detector under different extreme conditions. In this paper, we experimented with different radiation sources to investigate the imaging screening effect of the pixelated CdZnTe detector under ultrahigh irradiance. A donut-shaped irradiation image was obtained due to the increase in the X-ray tube current or the tube voltage. Moreover, statistical data revealed that the total count of all pixels was not significantly different, while the event-count of irradiated area pixels decreased significantly. A consequence of the screening effect was that the event counts redistributed among pixels that are located in the irradiated area, while the inner electric field was distorted. This leads to the catastrophic performance degradation of the central pixels. According to the Poisson equation, we developed a theoretical model of the CdZnTe detector using the finite element software COMSOL to enable an in-depth investigation of carrier collection in the CdZnTe crystal. A comparison between the simulations and the test results showed that pixels in the central irradiated area are completely screened under the ultrahigh irradiance because of the emergence of the relatively higher potential region, which can distort the electron drift path. Furthermore, the photon-generated signal can be collected only partly at the edge of the irradiated area, which was relatively stable because the collection area in the CdZnTe volume was relatively limited. The imaging results deduced from the simulations are well consistent with the experimental data. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a new method to calibrate the absolute sensitivity of a soft X-ray streak camera (SXRSC). The calibrations are done in the static mode by using a small laser-produced X-ray source. A calibrated X-ray CCD is used as a secondary standard detector to monitor the X-ray source intensity. In addition, two sets of holographic flat-field grating spectrometers are chosen as the spectral discrimination systems of the SXRSC and the X-ray CCD. The absolute sensitivity of the SXRSC is obtained by comparing the signal counts of the SXRSC to the output counts of the X-ray CCD. Results show that the calibrated spectrum covers the range from 200 eV to 1040 eV. The change of the absolute sensitivity in the vicinity of the K-edge of the carbon can also be clearly seen. The experimental values agree with the calculated values to within 29% error. Compared with previous calibration methods, the proposed method has several advantages: a wide spectral range, high accuracy, and simple data processing. Our calibration results can be used to make quantitative X-ray flux measurements in laser fusion research.