The effect of molecular nitrogen exposure on the surfaces of InP(100)modified by potassium overlayers is investigated by core-level and valence-band photoemission spectroscopy using Synchrotron radiation.In comparison...The effect of molecular nitrogen exposure on the surfaces of InP(100)modified by potassium overlayers is investigated by core-level and valence-band photoemission spectroscopy using Synchrotron radiation.In comparison with InP(110)surface,we found the promotion is much stronger for InP(100)surface due to the central role of surface defects in the promotion;furthermore,in contrast with K-promoted oxidation of InP(100)where the bonding is observed between indium and oxygen,indium atoms did not react directly with nitrogen atoms during the K-promoted nitridation of InP(100).展开更多
A higher-harmonic cavity will be used to increase the beam lifetime and suppress coupled-bunch instabilities for Hefei Light Source-II. In this paper, results simulated by the particle-tracking model confirm that tuni...A higher-harmonic cavity will be used to increase the beam lifetime and suppress coupled-bunch instabilities for Hefei Light Source-II. In this paper, results simulated by the particle-tracking model confirm that tuning in the harmonic cavity may suppress the parasitic coupled-bunch instabilities. The factors calculated for lifetime improvement are larger than 2.5. The 3rd and 4th harmonic cavities have been designed. In particular, the absorbers and antenna couplers are applied in harmonic cavities to damp the higher order modes. Finally, the 4th harmonic cavity similar to the Duke＇s RF cavity will be used for HLS-II.展开更多
Methods The method of longitudinal injection to an ultra-low emittance storage ring by a sine wave kicker is investigated in this paper.Beam dynamics of the injected and stored beams are both studied.With a third-harm...Methods The method of longitudinal injection to an ultra-low emittance storage ring by a sine wave kicker is investigated in this paper.Beam dynamics of the injected and stored beams are both studied.With a third-harmonic kicker,the emittance and the orbit of the stored beam can be well preserved and the injection efficiency can reach 100%.展开更多
基金Supported by the National Natutal Science Foundation of Chinaby Hefei National Synchrotron Radiation Laboratory.
文摘The effect of molecular nitrogen exposure on the surfaces of InP(100)modified by potassium overlayers is investigated by core-level and valence-band photoemission spectroscopy using Synchrotron radiation.In comparison with InP(110)surface,we found the promotion is much stronger for InP(100)surface due to the central role of surface defects in the promotion;furthermore,in contrast with K-promoted oxidation of InP(100)where the bonding is observed between indium and oxygen,indium atoms did not react directly with nitrogen atoms during the K-promoted nitridation of InP(100).
基金Supported by National Natural Science Foundation of China (10675116)Major State Basic Research Development Programme of China(2011CB808301)
文摘A higher-harmonic cavity will be used to increase the beam lifetime and suppress coupled-bunch instabilities for Hefei Light Source-II. In this paper, results simulated by the particle-tracking model confirm that tuning in the harmonic cavity may suppress the parasitic coupled-bunch instabilities. The factors calculated for lifetime improvement are larger than 2.5. The 3rd and 4th harmonic cavities have been designed. In particular, the absorbers and antenna couplers are applied in harmonic cavities to damp the higher order modes. Finally, the 4th harmonic cavity similar to the Duke＇s RF cavity will be used for HLS-II.
基金This work was supported by National Key Research and Development Program of China(2016YFA0402001).
文摘Methods The method of longitudinal injection to an ultra-low emittance storage ring by a sine wave kicker is investigated in this paper.Beam dynamics of the injected and stored beams are both studied.With a third-harmonic kicker,the emittance and the orbit of the stored beam can be well preserved and the injection efficiency can reach 100%.
