Transmission energy spectra of 530 keV H^(+) ion penetrating 140μm thick seed coat of maize and fruit peel of grape with thickness of 100μm were measured.The result indicates that these thick biological targets,as s...Transmission energy spectra of 530 keV H^(+) ion penetrating 140μm thick seed coat of maize and fruit peel of grape with thickness of 100μm were measured.The result indicates that these thick biological targets,as seen by the penetrating ions,are inhomogeneous,and there are open“channel like”paths along which the incidentions can transmit the targets easily.While most of the incident ions are stopped in the targets,some of the transmitting ions only lose a small fraction of their initial incident energy.The transmission energy spectra show a pure electronic stopping feature.Transmission electron microscope(TEM)micrographes taken from the samples of seed coat of maize and fruit peel of tomato with thickness of 60μm indicate that 150keV electron beam from the TEM can penetrate the thick samples to give very good images with clear contrasts.展开更多
Experimental evidence of abnormally deep penetration in some botanical targets by low-energy ion beams is presented.The energy spectra of 818 keV He^(+)ions penetrating a 70μm thick seed coat of maize,fruit peel of g...Experimental evidence of abnormally deep penetration in some botanical targets by low-energy ion beams is presented.The energy spectra of 818 keV He^(+)ions penetrating a 70μm thick seed coat of maize,fruit peel of grape and of tomato all have a common feature.The leading edges of these broad spectra indicate that some of the penetrating ions pass through the thick targets easily and only lose a small fraction of their initial incident energy.Rutherford backscattering spectrometry and electron microprobe measurements are used to determine the argon concentration in multilayer samples of the seed coat of maize implanted by 200 keV Ar^(+)ions.The results show that about 10%of the Ar^(+)ions can penetrate deeper than~100μm in these samples.展开更多
The optical waveguide was formed on an LiNbO_(3) substrate by 2.6 MeV nickel ions implantation to the dose of 9×10^(14) ions/cm^(2).Five dark modes were observed by the prism coupling technique.The refractive ind...The optical waveguide was formed on an LiNbO_(3) substrate by 2.6 MeV nickel ions implantation to the dose of 9×10^(14) ions/cm^(2).Five dark modes were observed by the prism coupling technique.The refractive index profile was obtained by using the reflectivity calculation method.A large index decrease was found in the guiding region and in the optical barrier,which is somewhat different from that of the LiNbO_(3) waveguide formed by the MeV He+ions.The position of the optical barrier is deeper than that of the damage peak calculated by TRIM'90(Transport of Ions in Matter)code.The crystal lattice damage in the guiding region caused by the Ni+ion implantation was analysed by the Rutherford backscattering/channelling technique.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.19890300in part by the Foundation for Ph.D.Education Programs from the National Education Commission of China under Grant No.96042208.
文摘Transmission energy spectra of 530 keV H^(+) ion penetrating 140μm thick seed coat of maize and fruit peel of grape with thickness of 100μm were measured.The result indicates that these thick biological targets,as seen by the penetrating ions,are inhomogeneous,and there are open“channel like”paths along which the incidentions can transmit the targets easily.While most of the incident ions are stopped in the targets,some of the transmitting ions only lose a small fraction of their initial incident energy.The transmission energy spectra show a pure electronic stopping feature.Transmission electron microscope(TEM)micrographes taken from the samples of seed coat of maize and fruit peel of tomato with thickness of 60μm indicate that 150keV electron beam from the TEM can penetrate the thick samples to give very good images with clear contrasts.
基金Supported by the National Natural Science Foundation of China under Grant No.19890300by the Foundation for Doctoral Education Programs from the Education Ministry of China under Grant No.96042208.
文摘Experimental evidence of abnormally deep penetration in some botanical targets by low-energy ion beams is presented.The energy spectra of 818 keV He^(+)ions penetrating a 70μm thick seed coat of maize,fruit peel of grape and of tomato all have a common feature.The leading edges of these broad spectra indicate that some of the penetrating ions pass through the thick targets easily and only lose a small fraction of their initial incident energy.Rutherford backscattering spectrometry and electron microprobe measurements are used to determine the argon concentration in multilayer samples of the seed coat of maize implanted by 200 keV Ar^(+)ions.The results show that about 10%of the Ar^(+)ions can penetrate deeper than~100μm in these samples.
基金Supported by the National Natural Science Foundation of China under grant No.19875032Natural Science Foundation of Shandong Province.
文摘The optical waveguide was formed on an LiNbO_(3) substrate by 2.6 MeV nickel ions implantation to the dose of 9×10^(14) ions/cm^(2).Five dark modes were observed by the prism coupling technique.The refractive index profile was obtained by using the reflectivity calculation method.A large index decrease was found in the guiding region and in the optical barrier,which is somewhat different from that of the LiNbO_(3) waveguide formed by the MeV He+ions.The position of the optical barrier is deeper than that of the damage peak calculated by TRIM'90(Transport of Ions in Matter)code.The crystal lattice damage in the guiding region caused by the Ni+ion implantation was analysed by the Rutherford backscattering/channelling technique.
