• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.461-463
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• 2004

We investigate the role of secondary electrons in galaxy clusters and in ultra-luminous infrared galaxies (ULIGs). The radio emission in galaxy clusters and ULIGs is believed to be produced by the synchrotron radiation of relativistic electrons. Nonetheless, the sources of these relativistic electrons are still unclear. Relativistic secondary electrons can be produced from the hadronic interactions of cosmic-ray nuclei with the intra-cluster media (ICM) of galaxy clusters and the dense molecular clouds of ULIGs. We estimate the contribution of the secondary electrons in galaxy clusters and ULIGs by comparing observational results with theoretical calculations for the radio emission in these sources. We find that the radio halos of galaxy clusters can not be produced from the secondary electrons; on the other hand, at least for some ULIGs, the radio emission can be dominated by the synchrotron emission of the secondary electrons.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.177-181
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• 2001

The conversion efficiency of a cesium iodine coated micro-channel plate is studied. We use the EGS4 code to transport photons and generated electrons until their energies become less than 1keV and 10keV respectively. Among the generated electrons, the emission from the secondary electrons located within the escape depth of 56nm from the photo-converter boundary is estimated by integrating the product of the secondary electrons with a probability depending only on their geometric locations. The secondary electron emission from the generated electrons of energy higher than 100eV is estimated by the 'universal yield curve'. The sum of these provides an estimate for the secondary electron yield and we show that results of applying this algorithm agree with known experimental results. Using this algorithm, we computed secondary electron emissions from a micro-channel plate used in a gas electron multiplier detector that is currently being developed at Korea Atomic Energy Research Institute.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.4
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• pp.15-21
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• 2008

Secondary electron detectors used in scanning electron microscope accept secondary electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. In order to acquire images with good qualities, as many secondary electrons as possible should be reached to the detector. To realize this it is very important to select an appropriate mounting position and angle of the detector inside the chamber of scanning electron microscope. In this paper, a number of numerical simulations are performed to explore the relationships between detection rates of secondary electrons and the values of some parameters, such as distances between the detector and sample, relative mounting positions of scintillator positioned inside the detector with respect to detector cover, two types of mounting angles of the detector. The relationships between detection rates and applied voltages to corona ring and faraday cage, and energies of secondary electrons are investigated as well.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.953-956
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• 2008

Using the theoretical model of Auger electron emission, effects of MgO properties which include band gap energy, escape probability, gas ion, and doping elements on the yield of secondary electron emission were examined. The results indicated that the band gap of MgO must be decreased and escape probability must be enhanced in order to increase the yield of secondary electrons from Xe ions and that may proved to be a critical for achieving high luminance efficacy in ac-PDPs.

• Applied Microscopy
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• v.51
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• pp.15.1-15.2
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• 2021

Puccinia miscanthi teliospores were observed on the leaf surface of Miscanthus sinensis using a field emission scanning electron microscope. Details of teliospore mucilage could be visualized through the axial imaging of secondary electrons for a better understanding of pathogen behavior in rust diseases.

• Applied Microscopy
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• v.45 no.4
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• pp.214-217
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• 2015

This study introduces metal coating as an effective sample preparation method to remove charge-up caused by the shadow effect during field emission scanning electron microscope (FE-SEM) analysis of dynamic structured samples. During a FE-SEM analysis, charge-up occurs when the primary electrons (input electrons) that scan the specimens are not equal to the output electrons (secondary electrons, backscattered electrons, auger electrons, etc.) generated from the specimens. To remove charge-up, a metal layer of Pt, Au or Pd is applied on the surface of the sample. However, in some cases, charge-up still occurs due to the shadow effect. This study developed a coating method that effectively removes charge-up. By creating a converted sample stage capable of simultaneous tilt and rotation, the shadow effect was successfully removed, and image data without charge-up were obtained.

• Journal of radiological science and technology
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• v.1 no.1
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• pp.31-35
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• 1978

X-rays contribute to electron emission from material surfaces primarily through photoelectric interaction. A simple model is described for predicting the yield and energy spectrum of photon and Auger electrons emitted from materials exposed to X-ray with low energy. In this paper, We have calculated the yield of primary, Auger, and secondary, electrons. The results of the photoelectric yield model developed here suggests that. I) The angular distribution of emitted electrons(Per unit angle) is proportional to $sin{\theta}\;cos{\theta}$ for all electron energies and all components(Primary, Auger, or Secondary) II) The shape of the energy spectrum of the photoelectric yield is independent of angle. III) For this targets the forward and backward photoelectric yields are indentical.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.927-930
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• 2004

We report on a new type of a flat and thin display with a secondary emission electron source. In this display device electrons are multiplied between two secondary emission plates under a high frequency electric field. This principle has a few important advantages over a field emission display: the emission comes from flat plates, which reduces the life-time problems of ion bombardment of field emitter tips. Furthermore, the electron emission is space charge limited which gives a uniform electron distribution. The electrons are extracted from the source and accelerated to a phosphor screen to generate light. Gray levels are made by pulse width modulation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.513-517
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• 2004

The nature of the signals collected by an SEM(Scanning Electron Microscope) in order to form images are all dependent on the detector used to collect them, and the quality of an acquired image is strongly influenced by detector performance. Therefore, the development of detector with high performance is very important in pulling up the resolution of SEM. In this article, electron beam-specimen interactions, the detection principle of secondary electrons and backscattered electrons, and the structure of a conventional detector are described. The structure of an experimental apparatus for the future study on our hopeful novel electron detector is presented as well.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.923-928
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• 1997

An MCP (Microchannel Plate) is a secondary electron multiplier to detect and amplify electrons. An MCP has many rnicrochannels whose diameters range from 10 to 100pm and whose lengths range from 40 to 100times of the diameter. Each microchannel of the MCP amplifies electrons over IOOOtimes by the secondary electron emission. Even though MCPs have high performance for electron amplification, the application of MCPs is limited to high performance electronic equipments because of their high fabricating cost and the limit of increasing their size due to the conventional fabrication process. Therefore, in this work, microchannels of the MCP are manufactured by micro-drilling to reduce the cost of the MCP and to increase their size. Alumina green body with epoxy binder was machined for fabricating microchannels using a high speed air turbine spindle and micro-drills with diamond grinding abrasives. Then alumina MCP was fabricated through the sintering of the machined alumina green body.