The pulse time of arrival （TOA） is a determining parameter for accurate timing and positioning in X-ray pulsar navigation. The pulse TOA can be calculated by comparing the measured arrival time with the predicted ar...The pulse time of arrival （TOA） is a determining parameter for accurate timing and positioning in X-ray pulsar navigation. The pulse TOA can be calculated by comparing the measured arrival time with the predicted arrival time of the X-ray pulse for pulsar. In this study, in order to research the measurement of pulse arrival time, an experimental system is set up. The experimental system comprises a simulator of the X-ray pulsar, an X-ray detector, a time-measurement system, and a data-processing system. An X-ray detector base is proposed on the basis of the micro-channel plate （MCP）, which is sensitive to soft X-ray in the 1–10 keV band. The MCP-based detector, the structure and principle of the experimental system, and results of the pulse profile are described in detail. In addition, a discussion of the effects of different X-ray pulse periods and the quantum efficiency of the detector on pulse-profile signal-to-noise ratio （SNR） is presented. Experimental results reveal that the SNR of the measured pulse profile becomes enhanced as the quantum efficiency of the detector increases. The SNR of the pulse profile is higher when the period of the pulse is smaller at the same integral.展开更多
Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission （PIXE） technique to analyze eight ancient glasses unearthed from the provinces of Henan,Hubei,and Jiangsu,which allowes for a good ch...Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission （PIXE） technique to analyze eight ancient glasses unearthed from the provinces of Henan,Hubei,and Jiangsu,which allowes for a good characterization of the glass matrix and chemical compositions,is carried out.The results indicate that all the eight glass samples could be typically divided into three systems： faience （sample No.SZWG-4）,PbO-BaO-SiO 2 （sample Nos.NYWKI-5-1,HNWKII-88,and HNWKII-84）,and Na 2 OCaO-SiO 2 （sample Nos.HBWKI-16,HBWKI-17,HBWKI-18,and SZWG-1）.Additional relationships between the Raman spectra and parameters,such as residues of raw materials and opacifying agent,are also discussed by respectively comparing them with similar glass samples excavated from other historical sites.展开更多
Through the use of time and space integrated kiloelectronvolt （keV） spectroscopy, we investigate the thermal emission of plasma, which produces strong line emission from the titanium K shell （He-a at 4.7 keV and H-...Through the use of time and space integrated kiloelectronvolt （keV） spectroscopy, we investigate the thermal emission of plasma, which produces strong line emission from the titanium K shell （He-a at 4.7 keV and H-α at 4.9 keV）, created by laser. In order to optimize the conversion efficiency enhancement on titanium foils, the experiment is conducted under a variety of laser-driven intensity conditions. The X-ray emission intensity at 4.7 keV is measured and compared with prediction. The experimental result demonstrates that the solid Ti target laser-produced plasma （LPP） source has X-ray emission at 4.7 keV, which are all generated from electronic transitions in Ti ions at pulse width of 2.1 ns or 30 ps, the crudely evaluated He-α X-ray intensity appears to slightly increase with laser intensity enhancement, and the pre- pulse effect increases the conversion efficiency of the He-α X-ray. In addition, a 90-μm-thick Ti foil as a filter is used to transmit He-α X-ray at near 4.7 keV, creating a quasi-monochromatic transmission and greatly reducing the lower- and higher-energy background.展开更多
K-shell X-ray emission from a Cu nanowire target irradiated by an ultraintense femtosecond laser pulse is studied using an elliptically bent quartz crystal and imaging plate. The designed bent crystal spectrometer has...K-shell X-ray emission from a Cu nanowire target irradiated by an ultraintense femtosecond laser pulse is studied using an elliptically bent quartz crystal and imaging plate. The designed bent crystal spectrometer has better spectral resolution, which is higher than 1000. The absolute Ka radiation photon yields are obtained from the experimental results and the Monte-Carlo model. The conversion efficiency of the Cu Ka line is estimated to be 0.019% from the interaction of 4 J, 50-fs laser pulse irradiated on a Cu nanowire target. The high vield of K shell X-ray has important applications in X-ray emission source.展开更多
By measuring the emission spectra and the fluorescence lifetime of the ^4I13/2 state of Er^3＋ ions in Gd2SiO5 crystal at different temperatures, the effects of temperature on the spectra and the lifetime of the ^4I13...By measuring the emission spectra and the fluorescence lifetime of the ^4I13/2 state of Er^3＋ ions in Gd2SiO5 crystal at different temperatures, the effects of temperature on the spectra and the lifetime of the ^4I13/2 state are investigated. When the temperature increases, the emission line width for the ^4I13/2 →^4I15/2 transition is broadened, and the main emission lines at 1 596, 1 609, and 1 644 nm shifte toward shorter wavelengths. The measured lifetime of the ^4I13/2 state decreases from 13.2 to 8.4 ms with temperature increase from 13 to 300 K, which is mainly due to the temperature dependence of multiphonon relaxation between the ^4I13/2 and ^4I15/2 states and the changing population distribution among the Stark levels within the ^4I13/2 state. The experimental results imply that low temperature condition is better for the -l.6μm laser output.展开更多
We investigate terahertz radiation （T-rays） from a pentacene organic diode at room temperature. The quantum chemistry calculation for frequency-related Huang Rhys factor of pentacene is also carried out. The results...We investigate terahertz radiation （T-rays） from a pentacene organic diode at room temperature. The quantum chemistry calculation for frequency-related Huang Rhys factor of pentacene is also carried out. The results demonstrate that the T-rays can come from a bending vibration of pentacene skeleton after the energy of pentacene exeiton transferring to the vibrational excited state via electron-phonon coupling. Frequency and natural bond orbital analytics of pentacene and its derivatives are performed in order to explain the result and develop new materials to get higher emission. This work provides a new way to produce T-rays with a simDle device at room temperature.展开更多
文摘The pulse time of arrival （TOA） is a determining parameter for accurate timing and positioning in X-ray pulsar navigation. The pulse TOA can be calculated by comparing the measured arrival time with the predicted arrival time of the X-ray pulse for pulsar. In this study, in order to research the measurement of pulse arrival time, an experimental system is set up. The experimental system comprises a simulator of the X-ray pulsar, an X-ray detector, a time-measurement system, and a data-processing system. An X-ray detector base is proposed on the basis of the micro-channel plate （MCP）, which is sensitive to soft X-ray in the 1–10 keV band. The MCP-based detector, the structure and principle of the experimental system, and results of the pulse profile are described in detail. In addition, a discussion of the effects of different X-ray pulse periods and the quantum efficiency of the detector on pulse-profile signal-to-noise ratio （SNR） is presented. Experimental results reveal that the SNR of the measured pulse profile becomes enhanced as the quantum efficiency of the detector increases. The SNR of the pulse profile is higher when the period of the pulse is smaller at the same integral.
基金supported by the National Natural Science Foundation of China under Grant No.51072206
文摘Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission （PIXE） technique to analyze eight ancient glasses unearthed from the provinces of Henan,Hubei,and Jiangsu,which allowes for a good characterization of the glass matrix and chemical compositions,is carried out.The results indicate that all the eight glass samples could be typically divided into three systems： faience （sample No.SZWG-4）,PbO-BaO-SiO 2 （sample Nos.NYWKI-5-1,HNWKII-88,and HNWKII-84）,and Na 2 OCaO-SiO 2 （sample Nos.HBWKI-16,HBWKI-17,HBWKI-18,and SZWG-1）.Additional relationships between the Raman spectra and parameters,such as residues of raw materials and opacifying agent,are also discussed by respectively comparing them with similar glass samples excavated from other historical sites.
基金supported by the National "863" Program of China under Grant No. 2006AA804312
文摘Through the use of time and space integrated kiloelectronvolt （keV） spectroscopy, we investigate the thermal emission of plasma, which produces strong line emission from the titanium K shell （He-a at 4.7 keV and H-α at 4.9 keV）, created by laser. In order to optimize the conversion efficiency enhancement on titanium foils, the experiment is conducted under a variety of laser-driven intensity conditions. The X-ray emission intensity at 4.7 keV is measured and compared with prediction. The experimental result demonstrates that the solid Ti target laser-produced plasma （LPP） source has X-ray emission at 4.7 keV, which are all generated from electronic transitions in Ti ions at pulse width of 2.1 ns or 30 ps, the crudely evaluated He-α X-ray intensity appears to slightly increase with laser intensity enhancement, and the pre- pulse effect increases the conversion efficiency of the He-α X-ray. In addition, a 90-μm-thick Ti foil as a filter is used to transmit He-α X-ray at near 4.7 keV, creating a quasi-monochromatic transmission and greatly reducing the lower- and higher-energy background.
基金supported by the National Basic Research Program of China(Nos.011CB808100and2010CB923203)the National Natural Science Foundation of China(Nos.10974214and60921004)+1 种基金the Shanghai Science and Technology Talent Project(No.12XD1405200)the State Key Laboratory Program of Chinese Ministry of Science and Technology
文摘K-shell X-ray emission from a Cu nanowire target irradiated by an ultraintense femtosecond laser pulse is studied using an elliptically bent quartz crystal and imaging plate. The designed bent crystal spectrometer has better spectral resolution, which is higher than 1000. The absolute Ka radiation photon yields are obtained from the experimental results and the Monte-Carlo model. The conversion efficiency of the Cu Ka line is estimated to be 0.019% from the interaction of 4 J, 50-fs laser pulse irradiated on a Cu nanowire target. The high vield of K shell X-ray has important applications in X-ray emission source.
基金supported by the National Natural Science Foundation of China under Grant No. 90922029
文摘By measuring the emission spectra and the fluorescence lifetime of the ^4I13/2 state of Er^3＋ ions in Gd2SiO5 crystal at different temperatures, the effects of temperature on the spectra and the lifetime of the ^4I13/2 state are investigated. When the temperature increases, the emission line width for the ^4I13/2 →^4I15/2 transition is broadened, and the main emission lines at 1 596, 1 609, and 1 644 nm shifte toward shorter wavelengths. The measured lifetime of the ^4I13/2 state decreases from 13.2 to 8.4 ms with temperature increase from 13 to 300 K, which is mainly due to the temperature dependence of multiphonon relaxation between the ^4I13/2 and ^4I15/2 states and the changing population distribution among the Stark levels within the ^4I13/2 state. The experimental results imply that low temperature condition is better for the -l.6μm laser output.
基金supported by the National Science Foundation of China(Nos.51103054 and 91233113)the Ministry of Science and Technology of China(No.2013CB834705)the PCSIRT(No.20921003)
文摘We investigate terahertz radiation （T-rays） from a pentacene organic diode at room temperature. The quantum chemistry calculation for frequency-related Huang Rhys factor of pentacene is also carried out. The results demonstrate that the T-rays can come from a bending vibration of pentacene skeleton after the energy of pentacene exeiton transferring to the vibrational excited state via electron-phonon coupling. Frequency and natural bond orbital analytics of pentacene and its derivatives are performed in order to explain the result and develop new materials to get higher emission. This work provides a new way to produce T-rays with a simDle device at room temperature.
