Design Study and Fabrication of the Target/Ion Source to Generate a Li-8 Beam

Jeong-Jeung Dang 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.8

The Korea Multi-purpose Accelerator Complex (KOMAC) has developed a target/ion source (TIS) to generate a Li-8 radioactive isotope beam. The basic concept of the TIS is that the Li isotope is produced at a beryllium-oxide target irradiated by a 100-MeV proton beam, and Li atoms are ionized at a surface ionization ion source (SIS). Various numerical studies were conducted to design the TIS. The FLUKA code was utilized to estimate the Li-8 production rate and to find an optimum target thickness. Also, a simple Monte Carlo code was developed to estimate the ionization eciency of the SIS. In addition, a zero-dimensional power balance model of the TIS was developed, and a three-dimensional finite-element method was applied to obtain detailed thermal analysis results. On the basis of the thermal analysis, the related design and operation parameters were determined. The TIS designed by using various numerical studies was fabricated and tested. The TIS will be irradiated by a proton beam and generate Li-8 beam for fi-NMR facility.

A simple spectroscopic method to determine the degree of dissociation in hydrogen plasmas with wide-range spectrometer

Dang, Jeong-Jeung,Chung, Kyoung-Jae,Hwang, Y. S. American Institute of Physics 2016 Review of scientific instruments Vol.87 No.5

Development of the integrated application for the RF phase scan and the TOF analysis

Cho SungYun,Dang Jeong-Jeung,Song Young-Gi,Kim Jae-Ha,Lee Seung-Ho 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.8

The degree of the energy gain at each DTL tank has been measured using the Beam Position Monitors (BPMs) signals that are installed on the front and rear ends of the downstream tank. The proton beams are accelerated to the design energy with the phase setting synchronized condition into the DTL tank. To fnd an optimized setting through the energy calculation, an automatic scan algorithm is needed to measure the BPMs’ signals. Data processing was also needed including that calculate the optimized point compared to the PARMILA calculation. In KOMAC, RF phase scanning and Time-of-Flight (TOF) analysis programs were previously developed on diferent operating system platforms. The RF Phase Scan Tool (RPST) focused on automatic scanning and measured data collection based on Linux Centos7. The scan speed of the RPST was fxed at 1 Hz of the polling method, and the overall scan performance was not efcient. To develop a TOF Analysis Tool (TOFAT), a window-based Matlab with high utilization in data processing was adopted. As data sharing was necessary to transfer from RPST to TOFAT for data analysis, a fle was created with the same format. In this study, application which can be called the KOMAC RF Phase Scan Application (KRPSA) has been newly developed to solve diferent platform problems and low performance. The KRPSA is developed by Python-based mathematical functions, customized discriminant, and Experimental Physics and Industrial Control System (EPICS) software platforms. We introduce the development of the KRPSA including reliability validation compared with the TOFAT.

Upgrade Plan of the KOMAC Proton Linac for the Atmospheric Radiation Test on Semiconductor Devices

Kim Han-Sung,권혁중,Lee Seung-Hyun,Dang Jeong-Jeung,이필수,Yoon Sang-Pil,Cho Yong-Sub 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.5

At the Korea Multi-purpose Accelerator Complex (KOMAC), a 100-MeV high-power proton linac has been used for proton-beam irradiation services for various applications and research programs, including material science, bio-medical science, semiconductor applications, as well as nuclear physics and basic science, since commissioning of the machine in 2013. Recently, demands for fast neutrons from users in the semiconductor industries are increasing to test the semiconductor device SER (soft error rate) or SEE (single event effect). At present, we provide pilot services to users with pulsed white-spectrum neutrons (max. neutron energy ~100 MeV) generated at the beam dump, which is made of copper. However, the neutron energy should be increased at least to 200 MeV to meet international standards such as ISO26262 or JEDEC89A. For the upgrade of the linac energy to 200 MeV, we conducted a preliminary design study, including superconducting radio-frequency (SRF) based linac structure, a neutron generation target and a neutron utilization facility. The upgrade plan for the KOMAC linac, along with the preliminary results of the design study on the superconducting linac and neutron generation facility, will be given in this paper.

Enhancement of negative hydrogen ion production at low pressure by controlling the electron kinetics property with transverse magnetic field

Kim, June Young,Cho, Won-Hwi,Dang, Jeong-Jeung,Kim, Seongcheol,Chung, Kyoung-Jae,Hwang, Y S IOP 2016 Plasma sources science & technology Vol.25 No.6

<P>In a volume production H<SUP>−</SUP> ion source, independent control of electron energy distribution between the driver region and the extraction region is crucial for the efficient production of H<SUP>−</SUP> ions due to its unique volume production mechanism. However, at the low pressure regime compatible to ITER operation, it is difficult to control electron energy distribution separately because the nonlocal property dominates the electron kinetics. In this work, we suggest a new method to control the locality of electron kinetics. In this method, an additional pair of permanent magnets is introduced in the vicinity of the skin layer, differently from the conventional method in which the magnetic filter field was strengthened in the extraction region. This magnetic field shortens the energy relaxation length and changes the electron kinetics from nonlocal to local even for low pressure discharges. In this paper, we show that the locality of electron kinetics can be effectively controlled by the additional magnetic field near the skin layer by measuring the electron temperature profile along the center of the discharge chamber as well as by comparing electron energy probability function shapes for different strengths of magnetic field. Using this new method, we demonstrate that control of locality of electron kinetics can greatly enhance the production of H<SUP>−</SUP> ions in the extraction region by measuring H<SUP>−</SUP> ion beam current extracted from the plasma source.</P>

Role of dopamine D1 receptor in 3-fluoromethamphetamine-induced neurotoxicity in mice

Nguyen, Phuong-Tram,Shin, Eun-Joo,Dang, Duy-Khanh,Tran, Hai-Quyen,Jang, Choon-Gon,Jeong, Ji Hoon,Lee, Yu Jeung,Lee, Hyo Jong,Lee, Yong Sup,Yamada, Kiyofumi,Nabeshima, Toshitaka,Kim, Hyoung-Chun Elsevier 2018 Neurochemistry International Vol.113 No.-

<P><B>Abstract</B></P> <P>3-Fluoromethamphetamine (3-FMA) is an illegal designer drug of methamphetamine (MA) derivative. Up to date, little is known about the neurotoxic potential of 3-FMA. In the present study, we investigated the role of dopamine receptors in neurotoxicity induced by 3-FMA in comparison with MA (35 mg/kg, i.p.) as a control drug. Here we found that 3-FMA (40, 60 or 80 mg/kg, i.p.) produced mortality in a dose-dependent manner in mice. Treatment with 3-FMA (40 mg/kg, i.p.) resulted in significant hyperthermia, oxidative stress and microgliosis (microglial differentiation into M1 phenotype) followed by pro-apoptotic changes and the induction of terminal deoxynucleotidyl transferase dUDP nick end labeling (TUNEL)-positive cells. Moreover, 3-FMA significantly produced dopaminergic impairments [i.e., increase in dopamine (DA) turnover rate and decreases in DA level, and in the expression of tyrosine hydroxylase (TH), dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT-2)] with behavioral impairments. These dopaminergic neurotoxic effects of 3-FMA were comparable to those of MA. SCH23390, a dopamine D1 receptor antagonist, but not sulpiride, a dopamine D2 receptor antagonist significantly attenuated 3-FMA-induced neurotoxicity. Although both SCH23390 and sulpiride attenuated MA-induced dopaminergic neurotoxicity, sulpiride is more effective than SCH23390 on the dopaminergic neurotoxicity. Interestingly, SCH23390 treatment positively modulated 3-FMA-induced microglial activation (i.e., SCH23390 inhibited M1 phenotype from 3-FMA insult, but activated M2 phenotype). Therefore, our results suggest that the activation of dopamine D1 receptor is critical to 3-FMA-induced neurotoxicity, while both dopamine D1 and D2 receptors (dopamine D2 receptor > dopamine D1 receptor) mediate MA-induced dopaminergic neurotoxicity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3-FMA facilitates mortality in a dose-dependent manner. </LI> <LI> 3-FMA-induced initial oxidative burdens are prerequisite for the neurotoxicity. </LI> <LI> D1R facilitates microglial and pro-apoptotic changes induced by 3-FMA. </LI> <LI> D1R mediates dopaminergic impairments induced by 3-FMA. </LI> <LI> The neurotoxicity induced by 3-FMA are comparable to that induced by MA. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source

Kim, June Young,Cho, Won-Hwi,Dang, Jeong-Jeung,Chung, Kyoung-Jae,Hwang, Y. S. American Institute of Physics 2016 Review of scientific instruments Vol.87 No.2

Ginsenoside Re protects against phencyclidine-induced behavioral changes and mitochondrial dysfunction via interactive modulation of glutathione peroxidase-1 and NADPH oxidase in the dorsolateral cortex of mice

Tran, The-Vinh,Shin, Eun-Joo,Dang, Duy-Khanh,Ko, Sung Kwon,Jeong, Ji Hoon,Nah, Seung-Yeol,Jang, Choon-Gon,Lee, Yu Jeung,Toriumi, Kazuya,Nabeshima, Toshitaka,Kim, Hyoung-Chun Elsevier 2017 Food and chemical toxicology Vol.110 No.-

<P><B>Abstract</B></P> <P>We investigated whether ginsenoside Re (Re) modulates phencyclidine (PCP)-induced sociability deficits and recognition memory impairments to extend our recent finding. We examined the role of GPx-1 gene in the pharmacological activity of Re against mitochondrial dysfunction induced by PCP in the dorsolateral cortex of mice. Since mitochondrial oxidative stress activates NADPH oxidase (PHOX), we applied PHOX inhibitor apocynin for evaluating interactive modulation between GPx-1 and PHOX against PCP neurotoxicity. Sociability deficits and recognition memory impairments induced by PCP were more pronounced in GPx-1 knockout (KO) than in wild type (WT) mice. PCP-induced mitochondrial oxidative stress, mitochondrial dysfunction, and membrane translocation of p47<I>phox</I> were more evident in GPx-1 KO than in WT. Re treatment significantly attenuated PCP-induced neurotoxic changes. Re also significantly attenuated PCP-induced sociability deficits and recognition memory impairments. The attenuation by Re was comparable to that by apocynin. The attenuation was more obvious in GPx-1 KO than in WT. Importantly, apocynin did not show any additional positive effects on the neuroprotective activity of Re, indicating that PHOX is a molecular target for therapeutic activity of Re. Our results suggest that Re requires interactive modulation between GPx activity and PHOX (p47<I>phox</I>) to exhibit neuroprotective potentials against PCP insult.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Genetic depletion of GPx-1 facilitates PCP-induced mitochondrial dysfunction, oxidative parameters and PHOX activity. </LI> <LI> Genetic depletion of GPx-1 facilitates sociability deficits and recognition memory impairments induced by PCP. </LI> <LI> Re-mediated protective potentials against PCP required the interactive modulation between GPx-1 and PHOX (p47<I>phox</I>). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Characterization of electron kinetics regime with electron energy probability functions in inductively coupled hydrogen plasmas

Kim, June Young,Cho, Won-Hwi,Dang, Jeong-Jeung,Chung, Kyoung-Jae,Hwang, Y. S. American Institute of Physics, 2016 Physics of plasmas Vol.23 No.2

Design of a Thomson scattering diagnostic system for VEST

Kim, Young-Gi,Lee, Jong Ha,Lee, Jeongwon,An, YoungHwa,Dang, Jeong Jeung,Jo, Jungmin,Lee, HyunYeong,Chung, Kyoung-Jae,Hwang, Y.S.,Na, Yong-Su Elsevier 2015 Fusion engineering and design Vol.96 No.-

<P><B>Abstract</B></P> <P>A Thomson scattering diagnostic system is designed for Versatile Experiment Spherical Torus (VEST) to measure the spatial profiles of the electron temperature. The system is carefully designed to collect a sufficient number of photoelectrons and to reduce the noise sources, since relatively low electron densities and temperatures are expected in VEST due to the limited power capacity at present. The target electron temperature and the density are 10–200eV and 5×10<SUP>18</SUP> m<SUP>−3</SUP>, respectively which are extrapolated from the data of triple Langmuir probes measuring the edge plasma parameters at <I>R</I> =0.75m by assuming a parabolic density profile. The collecting optics is designed to have a wide-view angle and low cost by using a commercial photographic lens of low f-number and high transmittance optical fiber bundle. The bandwidths of the interference filters in the polychromator are designed for reliable measurements within the target electron temperature range. As a photo detector which is coupled with the filters, an avalanche photodiode (APD) with a low dark current and an adequate quantum efficiency near the laser wavelength is selected for the high signal-to-noise ratio. The number of photons transferred to the polychromator and the number of photoelectrons in the APD are calculated. At the commissioning phase, an oscilloscope with a high sampling rate will be adopted to check the necessity of the noise reduction by multi-shot signal accumulation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A Thomson scattering system for Versatile Experiment Spherical Torus is designed. </LI> <LI> The system is designed with care for the plasma with a low target electron density. </LI> <LI> APD of low dark current and enhanced sensitivity for near infrared has been chosen. </LI> <LI> A collecting optics system will provide a sufficient number of photoelectrons. </LI> <LI> A designed polychromator is able to measure the electron temperature of 10–1000eV. </LI> </UL> </P>