Design,fabrication and characterization of the X-ray supermirrors

With the development of the multiplayer technology, the multilayer mirrors have been widely used in many fields, such as the soft X-ray astronomical telescope, soft X-ray microscopy, extreme ultraviolet lithography, applications of synchrotron radiation, plasma diagnosis, and so on. However, in the hard X-ray region, especially for the wavelength shorter than 0.1 nm, the optical elements based on the traditional multilayers or the single high-Z metal coatings cannot accommodate the advancemen…     

Time-resolved multispectral X-ray imaging with multi-channel Kirkpatrick-Baez microscope for plasma diagnostics at Shenguang-II laser facility

A time-resolved multispectral X-ray imaging approach with new version of multi-channel Kirkpatrick- Baez （KB） microscope is developed for laser plasma diagnostics at the kilo joule-class Shenguang-II laser facility （SG-II）. The microscope uses a total external reflection mirror in the sagittal direction and an array of multilayer mirrors in the tangential direction to obtain multiple individual high-resolution, high- throughput, and quasi-monochromatic X-ray images. The time evolution of the imploded target in multiple X-ray energy bands can be acquired when coupled with an X-ray streak camera. The experimental result of the time-resolved 2.5 and 3.0 keV dual-spectral self-emission imaging of the undoped CH shell target on SG-II is given.     

Negative Dispersion Mirrors in Ta2O5／SiO2 for Femtosecond Ti：Sapphire Lasers by Using Gires-Tournois Interferometers

We design and experimentally demonstrate some negative dispersion mirrors with optimized Gires-Zournois interferometers. The mirror structure is composed of 38 alternating Ta2 O5 and SiO2 layers and could be regarded as two sections: high-reflectivity section consisting of a series of quarter-wavelength optical thickness stacks and negative-dispersion section consisting of only 13 layers. The designed mirrors exhibit the expected performance.These mirrors were fabricated by using ion beam sputtering. By adopting such mirrors, dispersion of a modelocked femtosecond Ti:sapphire laser has been compensated for mostly. With two series of the mirrors, 32 fs and 15 fs pulses have been obtained respectively.     

Fabrication and characterization of sliced multilayer transmission grating for X-ray region

To develop high quality dispersion optics in the X-ray region, the sliced multilayer transmission grating is examined. Dynamical diffraction theory is used to calculate the diffraction property of this volume grating. A WSi 2 /Si multilayer with a d-spacing of 14.3 nm and bi-layer number of 300 is deposited on a superpolished silicon substrate by direct current magnetron sputtering technology. To make the transmission grating, the multilayer is sliced and thinned in the cross-section direction to a depth of 23-25 μm. The diffraction efficiency of the grating is measured at E = 8.05 keV, and the 1st-order efficiency is 19%. The sliced multilayer grating with large aspect ratio and nanometer period can be used for high efficiency and high dispersion optics in the X-ray region.     

Study of X-ray Kirkpatrick-Baez imaging with single layer

The X-ray Kirkpatrick-Baez （KB） imaging experiment with single layer is implemented. Based on the astigmatism aberration and residual geometric aberration of a single mirror, a KB system with 16^x mean magnification and approximately 0.45°grazing incidence angle is designed. The mirrors are deposited with an Ir layer of 20-am thickness. Au grids backlit by X-ray tube of 8 keV are imaged via the KB system on scintillator charge-coupled device （CCD）. In the ±80 #m field, resolutions of less than 5 #m are measured. The result is in good agreement with the simulated imaging.     

The simulation of soft X-ray optics by ray-tracing

The ray tracing program for soft X-ray optics simulation is presented. This program can be used to study X-ray imaging property, energy transportation and concentration of X-ray beams by various X-ray optics. As an example, the results of the simulation about imaging characteristics of the toroidal mirror are given.     

Energy spectrum of multi-radiation of X-rays in a low energy Mather-type plasma focus device

The multi-radiation of X-rays was investigated with special attention to their energy spectrum in a Mather-type plasma focus device （operated with argon gas）. The analysis is based on the effect of anomalous resistances. To study the energy spectrum, a four-channel diode X-ray spectrometer was used along with a special set of filters. The filters were suitable for detection of medium range X-rays as well as hard X-rays with energy exceeding 30 keV. The results indicate that the anomalous resistivity effect during the post pinch phase may cause multi-radiation of X-rays with a total duration of 300 ± 50 ns. The significant contribution of Cu-Kα was due to the medium range X-rays, nonetheless, hard X-rays with energies greater than 15 keV also participate in the process. The total emitted X-ray energy in the forms of Cu-K and Cu-K/3 was around 0.14 ± 0.02 （J/Sr） and 0.04 ±0.01 （J/Sr）, respectively. The total energy of the emitted hard X-ray （〉 15 keV） was around 0.12± 0.02 （J/Sr）.     

The Medium Energy X-ray telescope (ME) onboard the Insight-HXMT astronomy satellite

The Medium Energy X-ray telescope(ME) is one of the three main telescopes on board the Insight hard X-ray modulation telescope(Insight-HXMT) astronomy satellite. ME contains 1728 pixels of Si-PIN detectors sensitive in 5-30 ke V with a total geometrical area of 952 cm~2. The application specific integrated circuit(ASIC) chip, VA32TA6, is used to achieve low power consumption and low readout noise. The collimators define three kinds of field of views(FOVs) for the telescope, 1°×4°, 4°×4°,and blocked ones. Combination of such FOVs can be used to estimate the in-orbit X-ray and particle background components.The energy resolution of ME is ～3 ke V at 17.8 ke V(FWHM) and the time resolution is 255 μs. In this paper, we introduce the design and performance of ME.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics(MCAO)can offer a possibility of widening field of view(FOV)charac- terized by the isoplanatic angle.and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle.Considering the application of lidar,the isoplanatic angle's expressions of two deformable mirrors(DMs)MCAO for uplink and downlink are deduced.The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed,and the isoplanatic angles are further analyzed.The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude.Moreover,the optimal conjugate height changes with the propagation distance.     

A slope-based decoupling algorithm to simultaneously control dual deformable mirrors in a woofer–tweeter adaptive optics system

We propose a slope-based decoupling algorithm to simultaneously control the dual deformable mirrors(DMs) in a woofer–tweeter adaptive optics system. This algorithm can directly use the woofer's response matrix measured from a Shack–Hartmann wave-front sensor to construct a slope-based orthogonal basis, and then selectively distribute the largeamplitude low-order aberration to woofer DM and the remaining aberration to tweeter DM through the slope-based orthogonal basis. At the same moment, in order to avoid the two DMs generating opposite compensation, a constraint matrix used to reset tweeter control vector is convenient to be calculated with the slope-based orthogonal basis. Numeral simulation demonstrates that this algorithm has a good performance to control the adaptive optics system with dual DMs simultaneously. Compared with the typical decoupling algorithm, this algorithm can take full use of the compensation ability of woofer DM and release the stroke of tweeter DM to compensate high-order aberration. More importantly, it does not need to measure the accurate shape of tweeter's influence function and keeps better performance of restraining the coupling error with the continuous-dynamic aberration.