X-ray framing camera (XFC) is usually used as the principal diagnostic tool in inertial confinement fusion research. The methods on how to precisely calibrate the temporal resolution are important topics for XFC with several picoseconds gate time. A method to measure the temporal resolution of XFCs is proposed based on a high-power subpicosecond ultraviolet laser facility called LLG-ultimate. In our method, series of duraluminium alloy stepped reflective surfaces are used to separate the incident laser beam into sequentially delayed beams with equal size, spacing, and time interval. The temporal resolution of XFC can be measured if the sequentially delayed beams irradiate a gold photocathode microstrip line while the high-voltage pulse transferring along the same area simultaneously. A Fabry–Perot etalon is placed in the light path, improving the probability of synchronization of the voltage pulse and laser pulse. The accuracy of this measurement method can be very high by reducing the time interval of the sequentially delayed beams.
In the field of target diagnostics for Initial Confinement Fusion experiment, high resolution X-ray imaging system is
seriously necessary to record the evolution details of target ablation-front disturbance at different energy points of backlight
conditions. Kirkpatrick-Baez mirror is a wide used imaging system to achieve a large efficient field of view with high
spatial resolution and energy transmitting capability. In this paper, we designed a novel type of reflective microscope based
on Kirkpatrick-Baez structure, and this system can achieve 5μm spatial resolution at 600μm field of view specific energy
point in one dimension.
A Kirkpatrick-Baez (KB) x-ray microscope has been developed for the diagnostics of inertial confinement fusion (ICF).
The KB microscope system works around 2.5keV with the magnification of 20. It consists of two spherical multilayer
mirrors. The grazing angle is 3.575° at 2.5keV. The influence of the slope error of optical components and the alignment
errors is simulated by SHADOW software. The mechanical structure which can perform fine tuning is designed.
Experiment result with Manson x-ray source shows that the spatial resolution of the system is about 3-4μm over a field
of view of 200μm.
A large-field high-resolution x-ray microscope was developed for multi-keV time-resolved x-ray imaging diagnostics of laser plasma at the Shenguang-III prototype facility. The microscope consists of Kirkpatrick–Baez amélioré (KBA) bimirrors and a KB single mirror corresponding to the imaging and temporal directions of a streak camera, respectively. KBA bimirrors coated with an Ir single layer were used to obtain high spatial resolutions within the millimeter-range field of view, and a KB mirror coated with Cr/C multilayers was used to obtain a specific spectral resolution around 4.3 keV. This study describes details of the microscope with regard to its optical design, mirror coatings, and assembly method. The experimental imaging results of the grid with 3 to 5 μm spatial resolution are also shown.
The radial structure of core temperature and density is very important to benchmark theory simulation codes in Inertial confinement fusion (ICF) studies. In this article, we gave a method to determinate the radial structure of core temperature and density by using the normalized intensity of core experimental x-ray image. The core emission model uses the average atom model (AA) and the radiation transport model assumes the local thermo dynamic equilibrium model (LTE). Calculated results show that: the full width at half maximum of core temperature is about 39.4μm which indicate that the hot spot diameter is such value and the full width at half maximum of core density is about 5μm. The hot spot convergence and the shell in-flight aspect ratio (IFAR) can be deduced approximately 7 and 7.5 respectively. The above assist us to better understand the implosion physics, and provide more information for benchmarking the simulation codes.
High speed X-ray scanning camera (XSC) is an extra precision temporal and spatial diagnostic instrument in the inertial
confinement fusion (ICF) experiment. In order to quantitatively analyze the measurement results, the spectral sensitivity
of XSC, which depends on the response of the transmission photocathode, is necessary to be absolutely calibrated. A
method of measuring the spectral response of Au and CsI transmission photocathodes of XSC is described. Based on
Beijing Synchrotron Radiation Facility (BSRF), Au and CsI transmission photocathodes with slits are calibrated in the
photon energy range of 60 eV-1500 eV and 2.1 keV-5.5 keV. Utilizing the quantum efficiency of the standard detector
AXUV-100, the calibrated quantum efficiency of Au and CsI photocathodes are derived. The calibration data agree well
with the photoelectric emission theory of Henke.
A micro-channel plate (MCP) transmissivity is calibrated using the 3B3 medium energy X-ray beamline (from 2.0 to 5.5keV) on Beijing Synchrotron Radiation Facility (BSRF). MCP transmissivity near the two ends of low-energy 2.0keV and high-energy 5.5keV is higher than the middle part. We calculate reflectivity and transmission in the pores array of MCP respectively, and take the experiment result into account synthetically. It uncovers that the grazing incident X-ray
in pores results in the total reflection, and the reflectivity rises as the X-ray energy decreases, which successfully explains the peculiar phenomena of the high transmissivity in low energy.