Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are...Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are realized in this experiment.The relative energy spectrum for ^(8)He was reconstructed with good statistics.The spectrum exhibits a structure of two resonant peaks,one at an excitation energy of about 3.0 and the other at about 4.14 MeV,respectively.Substantially larger cross section for the first resonance is observed in comparison to the results reported previously.展开更多
We report on the first observation of the neutron-rich nucleus^(131)Ag.This isotope was produced via fragmentation reactions of intense secondary radioactive ion beams,including 134,135Sn.The secondary beams were prod...We report on the first observation of the neutron-rich nucleus^(131)Ag.This isotope was produced via fragmentation reactions of intense secondary radioactive ion beams,including 134,135Sn.The secondary beams were produced from induced fission reactions from a stable 238U beam at 345 MeV/nucleon.Secondary reaction residues were selected by the ZeroDegree spectrometer and identified by measuring their magnetic rigidity,time of flight,energy loss,and total kinetic energy.展开更多
Ozone is one of the trace gases in atmosphere. Although it is very small in amount,it is of great importance to human being and biosphere because it absorbs effectively and cuts down the intensity of the solar ultravi...Ozone is one of the trace gases in atmosphere. Although it is very small in amount,it is of great importance to human being and biosphere because it absorbs effectively and cuts down the intensity of the solar ultraviolet radiation.In recent years, what the public are concerned of is the perturbation in the amount of O3 in the atmosphere resulted from human activities. The variation of ozone in atmosphere would affect photochemical reactions to a great extent. In addition, ozone acts as a thermal source in stratosphere. Con-展开更多
Microscopes in vacuum ultraviolet and soft X-ray regions using a normal incidence type of Schwarzschild objective are reviewed. The objective consists of a concave mirror and a convex mirror coated with a high reflect...Microscopes in vacuum ultraviolet and soft X-ray regions using a normal incidence type of Schwarzschild objective are reviewed. The objective consists of a concave mirror and a convex mirror coated with a high reflectance multilayer,having a large numerical aperture comparing with other objectives. The microscopes have been used to diagnose inertia-confinement-fusion plasmas,and to investigate small samples or microstructures of in- organic and organic materials by imaging them using laboratory light sources. Synchrotron radiation has been also used to obtain a microbeam for a photoelectron scanning microscope with a spatial resolution of 0.1 μm. The struc- ture and performance of two laboratory microscopes developed at Tohoku University are demonstrated. One of them is a soft X-ray emission imaging microscope. An image of an artificial pattern made of W and SiO2 on Si wafer by focusing Si L emission was presented. The other is an ultraviolet photoelectron scanning microscope using a He (he- lium) gas discharge lamp. The valence band spectra of a microcrystal of FeWO4 were presented. Furthermore other applications such as demagnifying optics for lithography and optics to gather fluorescence for emission spectroscopy are introduced.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11035001,10975006 and J1103206the National Basic Research Program of China under Grant No 2007CB815002.
文摘Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are realized in this experiment.The relative energy spectrum for ^(8)He was reconstructed with good statistics.The spectrum exhibits a structure of two resonant peaks,one at an excitation energy of about 3.0 and the other at about 4.14 MeV,respectively.Substantially larger cross section for the first resonance is observed in comparison to the results reported previously.
基金the National Basic Research Program of China under Grant No 2013CB834402the National Natural Science Foundation of China under Grant Nos 11035001 and 11275011.
文摘We report on the first observation of the neutron-rich nucleus^(131)Ag.This isotope was produced via fragmentation reactions of intense secondary radioactive ion beams,including 134,135Sn.The secondary beams were produced from induced fission reactions from a stable 238U beam at 345 MeV/nucleon.Secondary reaction residues were selected by the ZeroDegree spectrometer and identified by measuring their magnetic rigidity,time of flight,energy loss,and total kinetic energy.
文摘Ozone is one of the trace gases in atmosphere. Although it is very small in amount,it is of great importance to human being and biosphere because it absorbs effectively and cuts down the intensity of the solar ultraviolet radiation.In recent years, what the public are concerned of is the perturbation in the amount of O3 in the atmosphere resulted from human activities. The variation of ozone in atmosphere would affect photochemical reactions to a great extent. In addition, ozone acts as a thermal source in stratosphere. Con-
文摘Microscopes in vacuum ultraviolet and soft X-ray regions using a normal incidence type of Schwarzschild objective are reviewed. The objective consists of a concave mirror and a convex mirror coated with a high reflectance multilayer,having a large numerical aperture comparing with other objectives. The microscopes have been used to diagnose inertia-confinement-fusion plasmas,and to investigate small samples or microstructures of in- organic and organic materials by imaging them using laboratory light sources. Synchrotron radiation has been also used to obtain a microbeam for a photoelectron scanning microscope with a spatial resolution of 0.1 μm. The struc- ture and performance of two laboratory microscopes developed at Tohoku University are demonstrated. One of them is a soft X-ray emission imaging microscope. An image of an artificial pattern made of W and SiO2 on Si wafer by focusing Si L emission was presented. The other is an ultraviolet photoelectron scanning microscope using a He (he- lium) gas discharge lamp. The valence band spectra of a microcrystal of FeWO4 were presented. Furthermore other applications such as demagnifying optics for lithography and optics to gather fluorescence for emission spectroscopy are introduced.
