Study on Characteristics of the Light-Initiated High Explosive-Based Pulse Laser Initiation.

The silver acetylene silver nitrate loading technology of the light initiated high explosive, as one of important means to simulate the structural response of powerful pulsed X-ray, adopts the pulse laser initiation. It has advantages of improvement of practical control, heterogenous loading realization and simultaneous loading timeliness. In this paper, the physical and mathematical models of hot spot initiation and photochemical initiation of energetic materials under the action of laser are firstly established, and then the laser initiation mechanism of the light initiated high explosive is specifically analyzed, and the laser initiation experiment is conducted based on the optical adsorption property of the light initiated high explosive. From this study, the laser initiation thresholds of 193 nm, 266 nm, 532 nm, 1064 nm wavelengths are given, and they are 5.07 mJ/mm2, 6.77 mJ/mm2, 7.21 mJ/mm2 and 10.61 mJ/mm2, respectively, and the complete detonation process is verified by detonation velocity. This work technically supports the study of pulse laser initiation process, mechanism and explosion loading rule as well as the loading technology of the light initiated high explosive to simulate the structural response of X ray.

The Characterization of Silicone-Tungsten-Based Composites as Flexible Gamma-Ray Shields.

Robots are very essential for modern nuclear power plants to monitor equipment conditions and eliminate accidents, allowing one to reduce the radiations on personnel. As a novel robot, a soft robot with the advantages of more degrees of freedom and abilities of continuously bending and twisting has been proposed and developed for applications in nuclear power industry. Considering the radiation and high-temperature environment, the overall performance improvement of the flexible materials used in the soft nuclear robot, such as the tensile property and gamma-ray shielding property, is an important issue, which should be paid attention. Here, a flexible gamma-ray shielding material silicone-W-based composites were initially doped with nano titanium oxide and prepared, with the composition of 20 silicone-(80-x) W-(x) TiO2, where x varied from 0.1 to 2.0 wt.%. Structural investigations on SEM and EDS were performed to confirm the structure of the prepared composites and prove that all the chemicals were included in the compositions. Moreover, the tensile property of the composites at 25, 100, and 150 °C were investigated to study the effect of working temperature on the flexibility of the compositions. The attenuation characteristics including the linear attenuation coefficients and mass attenuation coefficients of the prepared silicone-W or silicone-W-TiO2-based composites with respect to gamma ray were investigated. The stability of the silicone-tungsten-TiO2-based composite at high temperature was studied for the first time. In addition, the influence of nano TiO2 additive on the property's variation of silicone-W-based composites was initially studied. The comparison of the properties such as the tensile elongation, thermal stability, and gamma-ray shielding of the synthesized silicone-W and silicone-W-TiO2 composites showed that the addition of nano TiO2 powders could be useful to develop novel gamma-ray-shielding materials for radiation protection of soft robots or other applications for which soft gamma-ray-shielding materials are needed.

The Blow-Off Impulse Equivalence of Typical Missile Homogeneous Al-Alloy under Multienergy Composite Spectrum Electron Beam and Powerful Pulsed X-ray.

The electron beam, one of the most effective approaches to simulate the irradiation effects of powerful pulsed X-ray in the laboratory, plays an important role in simulating the thermodynamic effects of powerful pulsed X-ray. This paper studies the thermodynamics equivalence between multienergy composite spectrum electron beam and blackbody spectrum X-ray, which is helpful to quickly determine the experimental parameters in the simulation experiment. The experimental data of electron beam are extrapolated by numerical calculation, to increase the range of energy flux. Through calculating the blow-off impulse of blackbody spectrum X-ray irradiation, we obtained the curve of X-ray blow-off impulse varying with energy flux, and then found two categories of equivalent relations-equal-energy flux and equal-impulse-by analyzing the calculation results of electron beam and X-ray blow-off impulse. Based on such relations, we could directly or indirectly obtain the results of blackbody spectrum X-ray irradiation blow-off impulse via electron beam experiment.

Study on X-ray Induced Two-Dimensional Thermal Shock Waves in Carbon/Phenolic.

Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code "RAMA" to simulate a two-dimensional thermal shock wave induced by X-ray. Then, we compare the numerical simulation results with the thermal shock wave stress generated by the same strong current electron beam via experiment to verify the correctness of the numerical simulation. Subsequently, we discuss and analyze the rules of thermal shock wave propagation in C/P material by further numerical simulation. The results reveal that the thermal shock wave represents different shapes and mechanisms by the radiation of 1 keV and 3 keV X-rays. The vaporization recoil phenomenon appears as a compression wave under 1 keV X-ray irradiation, and X-ray penetration is caused by thermal deformation under 3 keV X-ray irradiation. The thermal shock wave propagation exhibits two-dimensional characteristics, the energy deposition of 1 keV and 3 keV both decays exponentially, the energy deposition of 1 keV-peak soft X-ray is high, and the deposition depth is shallow, while the energy deposition of 3 keV-peak hard X-ray is low, and the deposition depth is deep. RAMA can successfully realize two-dimensional orthotropic elastoplastic constitutive relation, the corresponding program was designed and checked, and the calculation results for inspection are consistent with the theory. This study has great significance in the evaluation of anisotropic material protection under the radiation of intense X-rays.

The Activation of Ti-Zr-V-Hf Non-Evaporable Getter Films with Open-Cell Copper Metal Foam Substrates.

Secondary electron emission (SEE) inhibition and vacuum instability are two important issues in accelerators that may induce multiple effects in accelerators, such as power loss and beam lifetime reduction. In order to mitigate SEE and maintain high vacuum simultaneously, open-cell copper metal foam (OCMF) substrates with Ti-Zr-V-Hf non-evaporable getter (NEG) coatings are first proposed, and the properties of surface morphology, surface chemistry and secondary electron yield (SEY) were analyzed for the first time. According to the experimental results tested at 25 °C, the maximum SEY (δmax) of OCMF before and after Ti-Zr-V-Hf NEG film deposition were 1.25 and 1.22, respectively. The XPS spectra indicated chemical state changes of the metal elements (Ti, Zr, V and Hf) of the Ti-Zr-V-Hf NEG films after heating, suggesting that the NEG films can be activated after heating and used as getter pumps.