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Upgrade of the imaging X-ray crystal spectrometers continues in order to fulfill the high-performance diagnostics requirements on EAST. For the tangential spectrometer, a new large pixelated two-dimensional detector was deployed on tokamaks for time-resolved X-ray imaging. This vacuum-compatible detector has an area of 83.8 × 325.3 mm(2), a framing rate over 150 Hz, and water-cooling capability for long-pulse discharges. To effectively extend the temperature limit, a double-crystal assembly was designed to replace the previous single crystals for He-like argon line measurement. The tangential spectrometer employed two crystal slices attached to a common substrate and part of He- and H-like Ar spectra could be recorded on the same detector when crystals were chosen to have similar Bragg angles. This setup cannot only extend the measurable Te up to 10 keV in the core region, but also extend the spatial coverage since He-like argon ions will be present in the outer plasma region. Similarly, crystal slices for He-like iron and argon spectra were adopted on the poloidal spectrometer. Wavelength calibration for absolute rotation velocity measurement will be studied using cadmium characteristic L-shell X-ray lines excited by plasma radiation. A Cd foil is placed before the crystal and can be inserted and retracted for in situ wavelength calibration. The Geant4 code was used to estimate X-ray fluorescence yield and optimize the thickness of the foil.

This paper develops a set of digital volume correlation (DVC) algorithms to address 3-D deformation measurements of soft gels with the aid of laser-scanning confocal microscopy. As an extension of the well-developed digital image correlation (DIC) method, the present DVC approach adopts a three-dimensional zero-normalized cross-correlation criterion (3-D ZNCC) to perform volume correlation calculations. Based on a 3-D sum-table scheme and the fast Fourier transform technique, a fast algorithm is first proposed to accelerate the integer-voxel correlation computations. Subsequently, two kinds of sub-voxel registration algorithms, i.e., 3-D gradient-based algorithm and 3-D Newton–Raphson algorithm, are presented to obtain the sub-voxel displacement and strain fields of volume images before and after deformation. Both a series of computer-simulated digital volume images and an actual agarose gel sample randomly embedded with fluorescent particles are employed to verify the 3-D deformation measurement capability of the proposed DVC algorithms, which indicates that they are competent to acquire 3-D displacement and strain fields of soft gels.

A large single crystal of 0.95Na0.5Bi0.5TiO3–0.05BaTiO3 (0.95NBT–0.05BT) with dimensions of 35 mm diameter × 10 mm length was grown by the top-seeded-solution growth method (TSSG). X-ray powder diffraction results indicate that the as-grown 0.95NBT–0.05BT crystal is of a perovskite structure and belongs to the rhombohedral system. The dielectric, ferroelectric and piezoelectric properties were investigated in detail. The room temperature dielectric constants for unpoled ⟨0 0 1⟩, ⟨1 1 0⟩ and ⟨1 1 1⟩ oriented crystal samples are 1450, 1650 and 1750 at 1 kHz and decrease to 1050, 800 and 480 after poling. The remanent polarizations Pr of ⟨0 0 1⟩, ⟨1 1 0⟩ and ⟨1 1 1⟩ oriented crystal samples are 16.44 µC cm−2, 23.69 µC cm−2 and 27.63 µC cm−2 with the coercive fields Ec of 32.72 kV cm−1, 31.20 kV cm−1 and 28.15 kV cm−1, respectively. Interestingly, the piezoelectric constant d33 of the 0.95NBT–0.05BT crystal shows apparent anisotropy along its pseudocubic ⟨0 0 1⟩, ⟨1 1 0⟩ and ⟨1 1 1⟩ directions. The ⟨0 0 1⟩ poled 0.95NBT–0.05BT crystals show excellent piezoelectric properties with d33 = 280 pC N−1. However, the d33 values of the ⟨1 1 1⟩ oriented 0.95NBT–0.05BT crystal are only 90 pC N−1. The origin of apparent anisotropy in piezoelectric properties has been discussed in detail.

The pyroelectric properties of (1−x)Pb(Mg1∕3Nb2∕3)O3–xPbTiO3 (PMN–xPT) single crystals have been investigated over a broad composition range of 0.13⩽x⩽0.40. The best pyroelectric performances are achieved in ⟨111⟩-oriented PMN–0.26PT single crystal. At room temperature, the figures of merit for voltage responsivity and detectivity reach up to 0.11m2∕C and 15.3×10−5Pa−1∕2, respectively. These properties are superior to those of conventional pyroelectric ceramics that have been widely used in device applications. PMN–0.26PT single crystal also possesses a relative high Curie temperature (∼120°C) and a low thermal diffusivity (∼4.4×10−7m2∕s). Furthermore, the pyroelectric properties of PMN–xPT (x⩾0.26) single crystals are weak dependent on temperature and nearly independent of frequency in the experimental temperature range of 20–55°C and frequency range of 50–10000Hz. The superior pyroelectric performances of the single crystal make it a promising candidate for high-performance uncooled infrared detectors and thermal imagers.

Due to computational complexity of correlation searching, the digital image correlation (DIC) method is often extremely time consuming in image processing and optical measurement, which has limited its further applications to a great extent. This paper develops a fast recursive scheme to mathematically reduce the computational burden of the traditional DIC technique and therefore improve its efficiency in deformation calculation. A global sum-table approach is proposed to simplify the computations of all double sums arising in the zero-normalized cross-correlation coefficient (ZNCC). A fast recursive algorithm is established to accelerate the calculation of the cross-correlation term in the ZNCC. Both theoretical analysis and actual displacement acquisition are carried out to validate the performance of the new DIC algorithm, which indicates that the fast recursive scheme can improve computational efficiency of integer-pixel correlation searching by about 10 to 50 times in comparison with the classic DIC algorithm, on the condition of keeping the measurement accuracy.