• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.530-531
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• 2013

3 MeV protonirradiated SrTiO3 (STO) single crystal exhibits a blue and green mixed luminescence. However, the same proton irradiated STO deposited with very thin Pt layer does not show any luminescence. This Pt layer involved in preventing the damage caused by arcingthat comes from tens of kV surface voltage build-up due to secondary electron induced charge up at the surface of insulator during ion beam irradiation. It implies that luminescence of ion irradiated STO originated from the modified STO surface layer caused by arcing rather than direct ion beam irradiation effect. Atmospheric pressure plasma, a simple and cost-effective method, treated STO also exhibits the same kind of blue and green mixed luminescence as the ion beam treated STO, because this plasma also creates a surface damage layer by arcing.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2419-2431
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• 2023

Experiments related to Boron Neutron Capture Therapy (BNCT) accomplished at the Institute of Nuclear Techniques (INT), Budapest University of Technology and Economics (TUB) are presented. Relevant investigations are required before designing BNCT for vivo applications. Samples of relevant boron compounds (H₃BO₃, BDTPA) usually employed in BNCT were investigated with neutron beam. Channel #5 in the research reactor (100 kW) of INT-TUB provides the neutron beam. Boron samples are mounted on a carrier for neutron irradiation. The particle attenuation of several carrier materials was investigated, and the one with the lowest attenuation was selected. The effects of boron compound type, mass, and compound phase state were also investigated. To detect the emitted charged particles, a traditional ZnS(Ag) detector was employed. The neutron beam's interaction with the detector-detecting layer is investigated. Graphite (as a moderator) was employed to change the neutron beam's characteristics. The fast neutron beam was also thermalized by placing a portable fast neutron source in a paraffin container and irradiating the H₃BO₃. The obtained results suggest that the direct measurement approach appears to be insufficiently sensitive for determining the radiation dose committed by the Alpha particles from the ¹⁰B (n,α) reaction. As a result, a new approach must be used.

• Korean Journal of Materials Research
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• v.3 no.1
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• pp.65-71
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• 1993

Abstract The effect of final heat treatment and welding on the irradiation growth of Zircaloy-4 was investigated. As a simulation for neurtron irradiation, accelerated proton beam with the energy of 3.5MeV was used up to the proton fluence of 9.8 ${\times}{10^{21}}$p/$m^2$ in the present study. It was found that irradiation growth of the annealed specimen was the highest and that of the ${\beta}$-quenched specimen was the samllest among the present specimens. The magnitude of irradiation growth of the present specimens decreased by welding. The difference in the magnitude of irradiation growth of the present specimens with different final heat treatment and the effect of welding on it were quantitatively analyzed in terms of crystallographic texture by using Kearns number, f, which was calculated from the x-ray diffraction data.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.119-125
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• 2021

⁸²Sr for ⁸²Rb generator was produced through the irradiation of the proton beam on the ^nat.RbCI target at the target irradiation facility installed at the end of the Rl-dedicated beamline of the 100 MeV proton linear accelerator of KOMAC (Korea Multi-purpose Accelerator Complex). The average current of the proton beam was 1.2 µA for irradiation time of 150 min. For the separation and purification of the ⁸²Sr from ^nat.RbCI irradiated, Chelex-100 resin was used. The activities of ⁸²Sr in the irradiated ^nat.RbCI target solution and after purification were 45.29 µCi and 43.4 µCi, respectively. The separation and purification yield was 95.8%. As an adsorbent to be filled in the generator for ⁸²Sr adsorption hydrous tin oxide was selected. The adsorption yield of ⁸²Sr into the generator adsorbent was > 99 %, and the total amount of ⁸²Sr adsorbed to the generator was 21.6 µCi as of the day of the ⁸²Rb elution experiment. When the elution amount was 22 mL, the maximum⁸²Rb elution yield was 93.3%, and the elution yield increased as the flow rate increased. After the eluted ⁸²Rb was filled in the correction phantom of the small PET for animals, a PET image was taken. The image scan time was set to 5 min, and the phantom PET image was successfully obtained. As results of impurity analysis on eluted ⁸²Rb using ICP-MS, ^nat.Rb stable isotopes that compete in vivo of ⁸²Rb were identified as undetected levels and were determined to be No-Carrier-Added (NCA).

• Radiation Oncology Journal
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• v.33 no.4
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• pp.337-343
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• 2015

Purpose: The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. Materials and Methods: The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and the other treatment room is equipped with a dedicated pencil beam scanning nozzle. The proton beam generator including the cyclotron and the energy selection system can lower the energy of protons down to 70 MeV from the maximum 230 MeV. Results: The multi-purpose nozzle can deliver both wobbling proton beam and active scanning proton beam, and a multi-leaf collimator has been installed in the downstream of the nozzle. The dedicated scanning nozzle can deliver active scanning proton beam with a helium gas filled pipe minimizing unnecessary interactions with the air in the beam path. The equipment was provided by Sumitomo Heavy Industries Ltd., RayStation from RaySearch Laboratories AB is the selected treatment planning system, and data management will be handled by the MOSAIQ system from Elekta AB. Conclusion: The SMC-PTS located in Seoul, Korea, is scheduled to begin treating cancer patients in 2015.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.1
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• pp.97-101
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• 2024

In this paper, we present the implementation of proton beam irradiation test logic and test results for Xilinx's RFSoC FPGA. In addition to the FPGA function, RFSoC is a chip that integrates CPU, ADC, and DAC and is attracting attention in the defense and space industries aimed at reducing the size of the chip. In order to use these chips in a space environment, an analysis of radiation effects was required and radiation mitigation measures were required. Through the proton irradiation test, the logic to measure the radiation effect of RFSoC was designed. Logic for comparing values stored in memory with normal values was implemented, and protons were irradiated to RFSoC to measure SEU generated in the block memory area. To alleviate the occurrence of SEU in other areas, TMR and SEM were applied and designed. Through the test results, we intend to verify this test configuration and establish an environment in which logic design for satellites can be verified in the future.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.507-513
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• 2012

This research was performed to evaluate the superparamagnetic iron oxide nanoparticles'(SPIONs) cell toxicity and to measure the radiation cell survival curve changes of SPIONs-uptake glioblastoma multiforme cells. The results could be practically used as the fundamental data to ameliorate proton beam cancer therapy, for example, providing necessary GBM treatment dose in the proton beam therapy when the therapy takes advantage of SPIONs. The assessment of the toxicological evaluation of synthesized SPIONs was accomplished by MTT assay as an in vitro experiment. The results showed no meaningful differences in the cell survival rate at the $1-100{\mu}g/ml$ SPIONs concentrations, but the cell toxicity was shown as the cell survival rate decreased up to 74.2% at the $200{\mu}g/ml$ SPIONs concentration. Then, we measured each radiation cell survival curve for U373MG cells and SPIONs-uptake U373MG cells with 0~5 Gy of proton beam irradiations. It is learned from the analysis of the experimental results that the SPION-uptake cells' radiation survival rate was more rapidly decreased as the irradiation dose increased. In conclusion we confirmed that SPIONs-uptake in U373MG cells induces cell death at the much less dose than the lethal dose of SPION-non-uptake cell. This research shows that the therapeutic efficacy of glioblastoma multiforme treatment in proton beam therapy can be improved by SPIONs targeting to the GBM cells.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1351-1358
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• 2017

In this work, we investigated radiation hardness of GaN-based transistors which are strong candidates for next-generation power electronics. Field effect transistors with three types of gate structures including metal Schottky gate, recessed gate, and p-AlGaN layer gate were fabricated on AlGaN/GaN heterostructure on Si substrate. The devices were irradiated with energetic protons and alpha-particles. The irradiated transistors exhibited the reduction of on-current and the shift of threshold voltage which were attributed to displacement damage by incident energetic particles at high fluence. However, FET operation was still maintained and leakage characteristics were not degraded, suggesting that GaN-based FETs possess high potential for radiation-hardened electronics.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.101-104
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• 2011

Cellobiose dehydrogenase(CDH) as a hemoflavoenzyme is secreted out of cell in the cellulose degradation. As CDH strongly bound to amorphous cellulose, it helps cellulose hydrolysis by cellulase. CDH may have an important role of saccharification process for bioethanol production. In this study, Phanerochaete chrysosporium ATCC 32629 was selected for the production of CDH among other strains tested. The optimal temperature and pH of CDH produced by P. chrysosporium ATCC 32629 were ${55^{\circ}C}$ and 4, respectively. To improve the activity of CDH, the mutation of P. chrysosporium was performed using proton beam that has high energy level partially. As a result, P. chrysosporium mutant with the high activity was selected at 1.2 kGy in a range of 99.9% lethal rate. The CDH and $\beta$-glucosidase activities of mutant were 1.4 fold and 20 fold higher than those of wild strain. Therefore, P. chrysosporium mutant with the high activities of CDH and $\beta$-glucosidase was obtained from mutation by proton beam irradiation.

• Journal of the Korean Vacuum Society
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• v.22 no.5
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• pp.250-256
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• 2013

It is described that the proton beam induces micro-size defects and electronic deep levels in luminescence Thin Film. Coincidence Doppler Broadening Positron Annihilation Spectroscopy (CDBPAS) and Positron lifetime Spectroscopy were applied to study of characteristics of a poly crystal samples. In this investigation the numerical analysis of the Doppler spectra was employed to the determination of the shape parameter, S-parameter value. The samples were exposed by 3.0 MeV proton beams with the intensities ranging between 0 to ${\sim}10^{14}$ particles. The S-parameter values decreased as increased the proton beam, that indicates the protons trapped in vacancies. Lifetime ${\tau}_1$ shows that positrons are trapped in mono vacancies. Lifetime ${\tau}_2$ is not changed according to proton irradiation that indicate the cluster vacancies of the grain structure.