Impact and torsion pendulums are applied in impulse coupling experiments of high-energy laser irradiation of space debris. It is difficult to achieve a multi-pulse experiment and thus hard to analyze the multi-pulse i...Impact and torsion pendulums are applied in impulse coupling experiments of high-energy laser irradiation of space debris. It is difficult to achieve a multi-pulse experiment and thus hard to analyze the multi-pulse impulse coupling effect. Here, we designed a new recoil impulse experimental measurement system of non-contact, multidegrees of freedom, and multi-pulse irradiation. The system used a low-pressure and low-temperature vacuum chamber to simulate the space environment, the pinning effect of magnetic levitation to achieve aluminum target suspension, and high-speed cameras to record the displacement over time to calculate the impulse of the target.Then the impulse coupling experiment of multi-pulse laser irradiation on the aluminum target was performed.The result shows that the multi-pulse impulse coupling effect is not the linear accumulation of coupling results by every single-pulse and multi-pulse coefficient that decreases with the increase of the number of pulses, and eventually stabilizes as the decrease gets smaller.展开更多
Aluminum (99.6% purity) was implanted with nitrogen ions to a total dose of 6×10 17 cm -2 at different temperatures (from 50 ℃ to 400 ℃) by plasma based ion implantation (PBII). The surface microstructure was i...Aluminum (99.6% purity) was implanted with nitrogen ions to a total dose of 6×10 17 cm -2 at different temperatures (from 50 ℃ to 400 ℃) by plasma based ion implantation (PBII). The surface microstructure was investigated by glancing angle X ray diffraction (GXRD), X ray photoelectron spectroscopy (XPS) and cross sectional transmission electron microscopy (XTEM). The results of GXRD and XTEM showed that there was an amorphous layer on the outer surface, and fine dispersion of AlN precipitates was found under the amorphous layer. The size of AlN precipitates strongly depended on the target temperature, with the increase of the target temperature, the size of AlN precipitates became larger. The excess nitrogen atoms can diffuse or migrate to the lower nitrogen concentration regions by radiation enhanced diffusion. The results of XPS further indicated that it was easier to form AlN precipitates at a higher target temperature, and the depth profile of nitrogen broadened.展开更多
The thick target neutron yields （TTNYs） of deuteron-induced reaction on AI and Cu isotopes are analyzed by combining the improved nuclear models and particle transport effects. The modified Glauber model is employed...The thick target neutron yields （TTNYs） of deuteron-induced reaction on AI and Cu isotopes are analyzed by combining the improved nuclear models and particle transport effects. The modified Glauber model is employed mainly to produce the peak of double differential cross section for the breakup process, and the exciton model and the Hauser-Feshbach theory are used for the statistical processes. The thin-layer accumulation method is used to calculate the TTNYs considering the neutron attenuation effects in the target. The calculated results are compared with the existing experimental data, and the analysis method can predict the TTNY data well at the deuteron energy of 40 MeV.展开更多
文摘Impact and torsion pendulums are applied in impulse coupling experiments of high-energy laser irradiation of space debris. It is difficult to achieve a multi-pulse experiment and thus hard to analyze the multi-pulse impulse coupling effect. Here, we designed a new recoil impulse experimental measurement system of non-contact, multidegrees of freedom, and multi-pulse irradiation. The system used a low-pressure and low-temperature vacuum chamber to simulate the space environment, the pinning effect of magnetic levitation to achieve aluminum target suspension, and high-speed cameras to record the displacement over time to calculate the impulse of the target.Then the impulse coupling experiment of multi-pulse laser irradiation on the aluminum target was performed.The result shows that the multi-pulse impulse coupling effect is not the linear accumulation of coupling results by every single-pulse and multi-pulse coefficient that decreases with the increase of the number of pulses, and eventually stabilizes as the decrease gets smaller.
文摘Aluminum (99.6% purity) was implanted with nitrogen ions to a total dose of 6×10 17 cm -2 at different temperatures (from 50 ℃ to 400 ℃) by plasma based ion implantation (PBII). The surface microstructure was investigated by glancing angle X ray diffraction (GXRD), X ray photoelectron spectroscopy (XPS) and cross sectional transmission electron microscopy (XTEM). The results of GXRD and XTEM showed that there was an amorphous layer on the outer surface, and fine dispersion of AlN precipitates was found under the amorphous layer. The size of AlN precipitates strongly depended on the target temperature, with the increase of the target temperature, the size of AlN precipitates became larger. The excess nitrogen atoms can diffuse or migrate to the lower nitrogen concentration regions by radiation enhanced diffusion. The results of XPS further indicated that it was easier to form AlN precipitates at a higher target temperature, and the depth profile of nitrogen broadened.
基金Supported by the Project of China Academy of Engineering Physics under Grant No 2013B0103015
文摘The thick target neutron yields （TTNYs） of deuteron-induced reaction on AI and Cu isotopes are analyzed by combining the improved nuclear models and particle transport effects. The modified Glauber model is employed mainly to produce the peak of double differential cross section for the breakup process, and the exciton model and the Hauser-Feshbach theory are used for the statistical processes. The thin-layer accumulation method is used to calculate the TTNYs considering the neutron attenuation effects in the target. The calculated results are compared with the existing experimental data, and the analysis method can predict the TTNY data well at the deuteron energy of 40 MeV.
