文章利用实验结果分析了 5 4 HC0 4的阈值电压在不同剂量率下随总剂量的变化关系 ,对若干种加速实验方法进行了比较 ,认为 1 0 ke V X射线源可以作为对 MOS器件进行快速的加速实验性能测试的辐照源。从环境安全考虑 ,1 0 ke V X射线源...文章利用实验结果分析了 5 4 HC0 4的阈值电压在不同剂量率下随总剂量的变化关系 ,对若干种加速实验方法进行了比较 ,认为 1 0 ke V X射线源可以作为对 MOS器件进行快速的加速实验性能测试的辐照源。从环境安全考虑 ,1 0 ke V X射线源易于屏蔽 ,可以用于硅片级的参数测试 ,且花费远远小于封装后的器件在60 Co源上的性能测试 。展开更多
The application of keV ion beam in life science started in China several decades ago. In 1986, researchers initially studied the mutagenic effect of ion beam, and successfully applied it to plant breeding. Nowadays, i...The application of keV ion beam in life science started in China several decades ago. In 1986, researchers initially studied the mutagenic effect of ion beam, and successfully applied it to plant breeding. Nowadays, ion beam implantation technique has been extensively applied to many biological fields. This paper mainly introduces one of its important applications: genetic transformation mediated by keV ion beam.展开更多
Several hundred keV fast neutron radiography(HKFNR)can be a complementary technique to common thermal neutron radiography(TNR)and several MeV fast neutron radiography(MFNR).We tested HKFNR on a 4.5 MV Van de Graaff ac...Several hundred keV fast neutron radiography(HKFNR)can be a complementary technique to common thermal neutron radiography(TNR)and several MeV fast neutron radiography(MFNR).We tested HKFNR on a 4.5 MV Van de Graaff accelerator,and the experimental results show that the spatial resolution of this technique is better than MFNR and close to TNR.Several hundred keV fast neutrons can penetrate some thermal neutron absorbers such as Cd,and it is feasible to investigate its use on some materials which are transparent to cold/thermal neutrons,such as aluminum,using this technique.展开更多
The K-shell ionization cross sections of Cr, Ni and Cu elements by 7.5-25 keV electron impact have been measured.The experimental data have also been compared with the theoretical predictions of the Hippler and Mayol-...The K-shell ionization cross sections of Cr, Ni and Cu elements by 7.5-25 keV electron impact have been measured.The experimental data have also been compared with the theoretical predictions of the Hippler and Mayol-Salvat models. In general, it seems that the Mayol-Salvat model can provide a better description to our experimental data.展开更多
We fabricate high-quality A1/A1Ox/A1 junctions using improved bridge and bridge-free techniques at 30-keV e-beam voltage,in which the length of undercut and the size of junction can be well controlled by the pre-expos...We fabricate high-quality A1/A1Ox/A1 junctions using improved bridge and bridge-free techniques at 30-keV e-beam voltage,in which the length of undercut and the size of junction can be well controlled by the pre-exposure technique.The dose window is 5 times as large as that used in the usual Dolan bridge technique,making this technique much more robust.Similar results,comparable with those achieved using a 100-keV e-beam writer,are obtained,which indicate that the 30-keV e-beam writer could be an economic choice for the superconducting qubit fabrication.展开更多
External filtered neutron beams have been developed at the horizontal radial channels No. 4 of Dalat research reactor. In the material composition of the neutron filters, the primary material components of Iron, Alumi...External filtered neutron beams have been developed at the horizontal radial channels No. 4 of Dalat research reactor. In the material composition of the neutron filters, the primary material components of Iron, Aluminum, Nickel and Vanadium are used to obtain the mono-energetic neutron beams of 24 and 59 keV, with low level of Gamma and slow neutron background. A computer code and Monte-Carlo simulation technique were applied to optimize the filter configurations and to deduce the neutron energy distributions in the filtered beams. A hydrogen-filled proton recoil detector and the activation method with Gold foils were used to measure the neutron energy spectrum and flux of each beam at sample position. The results of experimental neutron fluxes are 6.1 × 105 and 5.3 × 105 n/cm2/s for 24 and 59 keV beams, respectively.展开更多
We measure the multiple ionization cross-section ratios Rk1 of Ar impacted by Cw＋ （q= 1-3） ions in the energy range of 20-500 keV/u. The measured ratios Rkl increase with the projectile energy at lower energies, an...We measure the multiple ionization cross-section ratios Rk1 of Ar impacted by Cw＋ （q= 1-3） ions in the energy range of 20-500 keV/u. The measured ratios Rkl increase with the projectile energy at lower energies, and reach the maximum at energies of 50-150 keV/u, then decrease for higher energies, We also use the classical over barrier ionization model to calculate the ratios Rk1, and the calculation results are in good agreement with the data, which suggest that the multiple ionization process is described by the sequential over-barrier ionization process,展开更多
文摘The application of keV ion beam in life science started in China several decades ago. In 1986, researchers initially studied the mutagenic effect of ion beam, and successfully applied it to plant breeding. Nowadays, ion beam implantation technique has been extensively applied to many biological fields. This paper mainly introduces one of its important applications: genetic transformation mediated by keV ion beam.
基金Supported by the National Basic Research Program of China under Grant No 2010CB833106。
文摘Several hundred keV fast neutron radiography(HKFNR)can be a complementary technique to common thermal neutron radiography(TNR)and several MeV fast neutron radiography(MFNR).We tested HKFNR on a 4.5 MV Van de Graaff accelerator,and the experimental results show that the spatial resolution of this technique is better than MFNR and close to TNR.Several hundred keV fast neutrons can penetrate some thermal neutron absorbers such as Cd,and it is feasible to investigate its use on some materials which are transparent to cold/thermal neutrons,such as aluminum,using this technique.
基金Supported by the National Natural Science Foundation of China under Grant No.19874045。
文摘The K-shell ionization cross sections of Cr, Ni and Cu elements by 7.5-25 keV electron impact have been measured.The experimental data have also been compared with the theoretical predictions of the Hippler and Mayol-Salvat models. In general, it seems that the Mayol-Salvat model can provide a better description to our experimental data.
基金supported by the National Natural Science Foundation of China(Grant Nos.91321310,11274156,11474152,11474153,61521001,and 11504165)the State Key Basic Research Program of China(Grant Nos.2011CB922104 and 2011CBA00205)
文摘We fabricate high-quality A1/A1Ox/A1 junctions using improved bridge and bridge-free techniques at 30-keV e-beam voltage,in which the length of undercut and the size of junction can be well controlled by the pre-exposure technique.The dose window is 5 times as large as that used in the usual Dolan bridge technique,making this technique much more robust.Similar results,comparable with those achieved using a 100-keV e-beam writer,are obtained,which indicate that the 30-keV e-beam writer could be an economic choice for the superconducting qubit fabrication.
文摘External filtered neutron beams have been developed at the horizontal radial channels No. 4 of Dalat research reactor. In the material composition of the neutron filters, the primary material components of Iron, Aluminum, Nickel and Vanadium are used to obtain the mono-energetic neutron beams of 24 and 59 keV, with low level of Gamma and slow neutron background. A computer code and Monte-Carlo simulation technique were applied to optimize the filter configurations and to deduce the neutron energy distributions in the filtered beams. A hydrogen-filled proton recoil detector and the activation method with Gold foils were used to measure the neutron energy spectrum and flux of each beam at sample position. The results of experimental neutron fluxes are 6.1 × 105 and 5.3 × 105 n/cm2/s for 24 and 59 keV beams, respectively.
文摘We measure the multiple ionization cross-section ratios Rk1 of Ar impacted by Cw＋ （q= 1-3） ions in the energy range of 20-500 keV/u. The measured ratios Rkl increase with the projectile energy at lower energies, and reach the maximum at energies of 50-150 keV/u, then decrease for higher energies, We also use the classical over barrier ionization model to calculate the ratios Rk1, and the calculation results are in good agreement with the data, which suggest that the multiple ionization process is described by the sequential over-barrier ionization process,
