• Proceedings of the KIPE Conference
• /
• 2003.07b
• /
• pp.942-948
• /
• 2003

This paper about the small electron beam irradiator for solar cell's efficiency. Many things are studied by method to increase conversion efficiency of solar cell. We selected electron beam by method for conversion efficiency of solar cell. Energy bands of this electron beam irradiator is 80keV(max.). And, solar cells that apply in this paper are crystal Si. Average efficiency of solar cell that applies in this experiment is 10$\%$. This system manufactured low energy electron beam irradiator. And, electron beam irradiation to solar cell in vacuum chamber of this irradiator. Irradiation area is 20*20 [mm2] by 40[keV].

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.487-487
• /
• 2011

Recently graphene has emerged as a fascinating 2D system in condensed-matter physics as well as a new material for the development of nanotechnology. The unusual electronic band structure of graphene allows it to exhibit a strong ambipolar electric field effect with high mobility. These properties lead to the possibility of its application in high-performance transparent conducting films (TCFs). Compared to indium tin oxide (ITO) electrodes, which have a typical sheet resistance of ${\sim}60{\Omega}$/sq and ~85 % transmittance in the visible range (400?900 nm), the CVD-grown graphene electrodes have a higher/flatter transmittance in the visible to IR region and are more robust under bending. Nevertheless, the lowest sheet resistance of the currently available CVD graphene electrodes is higher than that of ITO. Here, we report an ingenious strategy, irradiation of MeV electron beam (e-beam) at room temperature under ambient condition, for obtaining size-homogeneous gold nanoparticle decorated on graphene. The nano-particlization promoted by MeV e-beam irradiation was investigated by transmission electron microscopy, electron energy loss spectroscopy elemental mapping, and energy dispersive X-ray spectroscopy. These results clearly revealed that gold nanoparticle with 10 ~ 15 nm in mean size were decorated along the surface of the graphene after 1.5 MeV-e-beam irradiation. A chemical transformation and charge transfer for the metal gold nanoparticle were systematically explored by X-ray photoelectron spectroscopy and Raman spectroscopy. This approach advances the numerous applications of graphene films as transparent conducting electrodes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.268-269
• /
• 2008

Charging of spacecraft occurs in plasma and radiation environment. Especially, we focused on an accident caused by internal charging in a glass material that was used as the cover plate of solar panel array, and tried to measure the charge distribution in glass materials under electron beam irradiation by using a PEA (Pulsed Electro-Acoustic method) system. In the case of a quartz glass (pure $SiO_2$), no charge accumulation was observed either during or after the electron beam irradiation. On the contrary, positive charge accumulation was observed in glass samples containing metal-oxide components. It is found that the polarity of the observed charges depends on the contents of the impurities. To identify which impurity dominates the polarity of the accumulated charge, we measured charge distributions in several glass materials containing various metal-oxide components and calculated the trap energy depths from the charge decay characteristics of all glass samples.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.93-97
• /
• 2001

A new compact, low-energy electron beam irradiator has been developed. The core-loss of silicon steels can be reduced by magnetic-domain refinement method. The irradiator was developed for the application of core-loss reduction using the method. The beam energy of the irradiator can be varied from 35 to 80 keV and the maximum current is 3mA. The irradiation area is designed to be $30\times30mm2$ now and will be upgraded to $30\times150mm2$ using a scanning magnet and scanning cone. The electron beam generated from 3 mm diameter LaB6 is extracted to the air for the irradiation of the silicon steels in the air. A special irradiation port was developed for this low-energy irradiator. A havar foil with $4.08{\mu}m$ thickness were used for the window and a cold air-cooling system keeps the foil structure by removing heat at the window. The irradiator system and its operation characteristics will be discussed.

• Progress in Medical Physics
• /
• v.34 no.3
• /
• pp.33-39
• /
• 2023

Purpose: FLASH radiotherapy (RT) using ultra-high dose rate (>40 Gy/s) radiation is being studied worldwide. However, experimental studies such as preclinical studies using small animals are difficult to perform due to the limited availability of irradiation devices and methods for generating a FLASH beam. In this paper, we report the initial dosimetry results of a prototype electron linear accelerator (LINAC)-based irradiation system to perform ultra-high dose rate (UHDR) preclinical experiments. Methods: The present study used the prototype electron LINAC developed by the Research Center of Dongnam Institute of Radiological and Medical Sciences (DIRAMS) in Korea. We investigated the beam current dependence of the depth dose to determine the optimal beam current for preclinical experiments. The dose rate in the UHDR region was measured by film dosimetry. Results: Depth dose measurements showed that the optimal beam current for preclinical experiments was approximately 33 mA, corresponding to a mean energy of 4.4 MeV. Additionally, the average dose rates of 80.4 Gy/s and 162.0 Gy/s at a source-to-phantom surface distance of 30 cm were obtained at pulse repetition frequencies of 100 Hz and 200 Hz, respectively. The dose per pulse and instantaneous dose rate were estimated to be approximately 0.80 Gy and 3.8×10⁵ Gy/s, respectively. Conclusions: Film dosimetry verified the appropriate dose rates to perform FLASH RT preclinical studies using the developed electron-beam irradiator. However, further research on the development of innovative beam monitoring systems and stabilization of the accelerator beam is required.

• Journal of radiological science and technology
• /
• v.33 no.4
• /
• pp.387-394
• /
• 2010

In the field of healthcare, the conventional sterilization treatments have been replaced by irradiation methods which are in accordance with internationally well established quality standards. The quality control in radiation sterilization assures that the absorbed dose of the irradiated material is in agreement with its requirements and standards. The electron beam irradiation requires technical assessments of more process parameters than gamma irradiation does. Korea has witnessed wide uses of electron accelerators since early 2000 but there hasn't been research experiences relating to quality system in accordance with international standards. The new large scale e-beam irradiation system with the specification of 10 MeV, 8 kW was installed and operated in 2008 by Seoul Radiology Services Co. It consists of the electron accelerator, product handling system, safety, documentation and control subsystems into an integrated system to meet the requirement of the Good Manufacturing Practice such as process quality assurance and management of product tracking records. To implement the international standard such as EN ISO11137, it is necessary to understand the purposes aimed in the standard and carry out the tests following the procedures required. This study presented the specification of the e-beam facility and showed what its design requirements and features are. The test results on a variety of process parameters were presented and validated it they are within the required limits.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.42 no.6
• /
• pp.49-56
• /
• 2005

An electron microbeam system has been developed to investigate the biological effect of cells by irradiating cell-nuclei with low-energy and low-flux electrons. It is essential to discern the cell nucleus from its cytoplasm and the culture medium and to locateit exactly onto the beam exit. The irradiation speed at more than 10,000 cells per hour is another requisite for the observations on cellular response to have good statistics. Long-time labor with patience and high concentration is needed since the frames of $320{\times}240{\mu}m^2$ should be moved more than 500 times for irradiating more than 10,000 cells per an hour. This paper describes the electron microbeam system with a focus on the user interfaces concerning the process of automatically recognizing the cell nuclei and injecting electron beam into the target cell nuclei at the irradiation speed of more than 10,000 cell nuclei per hour.

• Journal of Radiation Industry
• /
• v.5 no.2
• /
• pp.159-164
• /
• 2011

A variety of natural polymers have been used as tissue engineering scaffolds, drug delivery system, and cosmetic materials due to their higher biocompatibility and water uptake. As a major component of extracellular matrix, hyaluronic acid consisting of D-glucuronic acid and N-acetylglucosamine has been popularly used as a hydrogel material. Even though it has good properties to be used in the tissue engineering and cosmetic industry, its higher viscosity has limited a potential use in a variety of applications; only low content should be applied in preparing above products. In the present study, we investigated the effect of electron beam irradiation on the properties of hyaluronic acid. Hyaluronic acid paste containing low contents of water changed to solution after electron beam irradiation ranging from 1 to 10 kGy, which didn't exhibit any alteration of surface properties and morphological change after freeze-drying. However, its viscosity was significantly decreased as absorbed dose increased, which was approximately one by hundred in comparison with the viscosity of original hyaluronic acid solution with same concentration. In addition, it can still interact with positive charged chitosan generating polyelectrolyte complex. Therefore, only viscosity was decreased after electron beam irradiation, whereas other properties of hyaluronic acid maintained. Consequently, these hyaluronic acids with lower viscosities can be used in a variety of applications in tissue engineering, drug delivery, and cosmetic industry.

• Proceedings of the KIPE Conference
• /
• 2001.07a
• /
• pp.109-113
• /
• 2001

Exhaustion and environmental problem are big problem of 21th century is flint energy and the importance of energy to alternate flint energy as being risen is embossed more. Photovoltaic system is occupying big flow along with wind force development among is many substitute energy has shortcoming that energy conversion efficiency falls behind than another thing substitute energy, This research investigates electron beam to specification energy to Module that was generalized and schematized difference of curved line after existing V-I efficiency characteristic curve and irradiation. And will analyze cause of Module's efficiency addition and subtraction by electron beam investigation.

• Applied Microscopy
• /
• v.52
• /
• pp.4.1-4.11
• /
• 2022

Field emission scanning electron microscopy (FESEM) is an essential tool for observing surface details of specimens in a high vacuum. A series of specimen procedures precludes the observations of living organisms, resulting in artifacts. To overcome these problems, Takahiko Hariyama and his colleagues proposed the concept of the "nanosuit" later referred to as "NanoSuit", describing a thin polymer layer placed on organisms to protect them in a high vacuum in 2013. The NanoSuit is formed rapidly by (i) electron beam irradiation, (ii) plasma irradiation, (iii) Tween 20 solution immersion, and (iv) surface shield enhancer (SSE) solution immersion. Without chemical fixation and metal coating, the NanoSuit-formed specimens allowed structural preservation and accurate element detection of insulating, wet specimens at high spatial resolution. NanoSuit-formed larvae were able to resume normal growth following FESEM observation. The method has been employed to observe unfixed and uncoated bacteria, multicellular organisms, and paraffin sections. These results suggest that the NanoSuit can be applied to prolong life in vacuo and overcome the limit of dead imaging of electron microscopy.