A novel energy analyzer with a simple structured Bessel box has been successfully developed and incorporated into ionization gauges and quadrupole mass spectrometers (QMS) to improve their measurement of the total and...A novel energy analyzer with a simple structured Bessel box has been successfully developed and incorporated into ionization gauges and quadrupole mass spectrometers (QMS) to improve their measurement of the total and partial pressures,respectively.We found that the energy analyzer may not only effectively separate the gas phase ions and electron stimulated desorption (ESD) ions produced in the ionizer,but also screen the ion collector from irradiation of the soft X rays and VUVphotons generated in the ionizer.The screening effects considerably better the trace impurity detection limit of the QMS down to a few tens ppb in the pressure range of 10 -3 Pa.The modified ionization gauge is capable of measuring pressure ranging from 10 -11 to 10 -6 Pa in the pulse counting mode and its upper limit may extends to 10 -3 Pa in DC ion current mode with typical sensitivities factor of(6.7±0.2)×10 -3 Pa -1 for N 2 and (2.3±0.2)×10 -3 Pa -1 for H 2,respectively.No ESD ions was observed in the simple looking spectrum obtained with the modified QMS.We also found that the energy spectra of fragment ions depend strongly on species of parent ions.展开更多
Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formati...Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formation mechanism of silver nanostructure was proposed. The results show that both the PVP and the light irradiation are the keys to in-situ growth of silver nanostructure on quartz glass substrates. The silver nanostructure of the substrates which finally grow up to 150 nm after 20 h irradiation exhibits irregular shape, and some of nanoparticles stack to form bilayer. A new broad band appears in the absorption spectra of the substrates due to the interparticle dipole?dipole coupling of surface plasmon resonance response of the triangular silver nanoplate particles, which red shifts 600?800 nm as the particles grow up. The substrates have an emission band centered at 400 nm on their fluorescence spectra, and the fluorescence intensity shrinks as the average size of the silver nanostructure increases. The strongest SERS signal of SERS-active substrate is fabricated after 16 h.展开更多
文摘A novel energy analyzer with a simple structured Bessel box has been successfully developed and incorporated into ionization gauges and quadrupole mass spectrometers (QMS) to improve their measurement of the total and partial pressures,respectively.We found that the energy analyzer may not only effectively separate the gas phase ions and electron stimulated desorption (ESD) ions produced in the ionizer,but also screen the ion collector from irradiation of the soft X rays and VUVphotons generated in the ionizer.The screening effects considerably better the trace impurity detection limit of the QMS down to a few tens ppb in the pressure range of 10 -3 Pa.The modified ionization gauge is capable of measuring pressure ranging from 10 -11 to 10 -6 Pa in the pulse counting mode and its upper limit may extends to 10 -3 Pa in DC ion current mode with typical sensitivities factor of(6.7±0.2)×10 -3 Pa -1 for N 2 and (2.3±0.2)×10 -3 Pa -1 for H 2,respectively.No ESD ions was observed in the simple looking spectrum obtained with the modified QMS.We also found that the energy spectra of fragment ions depend strongly on species of parent ions.
基金Projects(10804101,60908023)supported by the National Natural Science Foundation of ChinaProject(2007CB815102)supported by the National Basic Research Program of ChinaProject(2007B08007)supported by the Science and Technology Development Foundation of Chinese Academy of Engineering Physics
文摘Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formation mechanism of silver nanostructure was proposed. The results show that both the PVP and the light irradiation are the keys to in-situ growth of silver nanostructure on quartz glass substrates. The silver nanostructure of the substrates which finally grow up to 150 nm after 20 h irradiation exhibits irregular shape, and some of nanoparticles stack to form bilayer. A new broad band appears in the absorption spectra of the substrates due to the interparticle dipole?dipole coupling of surface plasmon resonance response of the triangular silver nanoplate particles, which red shifts 600?800 nm as the particles grow up. The substrates have an emission band centered at 400 nm on their fluorescence spectra, and the fluorescence intensity shrinks as the average size of the silver nanostructure increases. The strongest SERS signal of SERS-active substrate is fabricated after 16 h.
