摘要
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.19890300
in part by the Foundation for Ph.D.Education Programs from the National Education Commission of China under Grant No.96042208.
