• Title/Summary/Keyword: Charge dose

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A Study on Electrical properties of EPR by Irradiated by X-rays (방사선에 조사된 EPR 의 전기적 특성에 관한 연구)

  • Lee, Sung-Il;Iim, Gui-Yeul;Lee, Ho-Sik;Lee, Hee-Gab
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.565-568
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    • 2002
  • The value of charge current, discharge current, $\varepsilon_r$' $\varepsilon_r"$, residual voltage was measured inorder to investigate electric properties in Ethylene Prophylene Rubber for is irradiated $CO^{60}\gamma$ ray 0-38.1 Mrad. The value of charge current and the discharging current of the EPR is influenced by $CO^{60}-{\gamma}$-irradiation dose The charging current and the discharging current of EPR increase, depending on the ratio of degradation. As the irradiation dose is increased, the peak of residual voltage moves to the slorter time. The properties specific electric constant due to time variation was appeared dispersion by plentiful $CO^{60}-{\gamma}$-irradiation dose. The increase of peak in $\varepsilon_r"$ is attrib uted to the irratiation dose almost proportionally.

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Effect of the Co$^{60}$ -Rays due to Electric properties of EPR- (EPR의 전기특성에 미치는 방사선의 영향)

  • 이성일
    • Proceedings of the Safety Management and Science Conference
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    • 2002.11a
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    • pp.253-259
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    • 2002
  • The value of charge currnet, discharge current, ${\varepsilon}r^'$,${\varepsilon}r^{'}$ residual voltage was measured inorder to investigate electric properties in Ethylene Prophylene Rubber for is irradiated C0$^{60}$$\gamma$ ray 0~38.1 Mrad. The value of charge current and the discharging current of the EPR is influenced by C0$^{60}$-$\gamma$- irradiation dose. The charging current and the discharging current of EPR increas, depending on the ratio of degradation. As the irradiatin dose is increased, the peak of residual voltage moves to the slorter time. The properties specific electric constant due to time variation was appeared dispersion by plentiful C0$^{60}$$\gamma$- irradiation dose. The increase of peak in ${\varepsilon}r^{'}$ is attrib uted to the irratiation dose almost proportionally.

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Test of a Multilayer Dose-Verification Gaseous Detector with Raster-Scan-Mode Proton Beams

  • Lee, Kyong Sei;Ahn, Sung Hwan;Han, Youngyih;Hong, Byungsik;Kim, Sang Yeol;Park, Sung Keun
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.5
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    • pp.297-304
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    • 2015
  • A multilayer gaseous detector has been developed for fast dose-verification measurements of raster-scan-mode therapeutic beams in particle therapy. The detector, which was constructed with eight thin parallel-plate ionization chambers (PPICs) and polymethyl methacrylate (PMMA) absorber plates, is closely tissue-equivalent in a beam's eye view. The gas-electron signals, collected on the strips and pad arrays of each PPIC, were amplified and processed with a continuous charge.integration mode. The detector was tested with 190-MeV raster-scan-mode beams that were provided by the Proton Therapy Facility at Samsung Medical Center, Seoul, South Korea. The detector responses of the PPICs for a 190-MeV raster-scan-mode proton beam agreed well with the dose data, measured using a 2D ionization chamber array (Octavius model, PTW). Furthermore, in this study it was confirmed that the detector simultaneously tracked the doses induced at the PPICs by the fast-oscillating beam, with a scanning speed of 2 m s-1. Thus, it is anticipated that the present detector, composed of thin PPICs and operating in charge.integration mode, will allow medical scientists to perform reliable fast dose-verification measurements for typical dynamic mode therapeutic beams.

Study on the Reduction of Electron Contamination with A Cobalt-60 Gamma Ray (코발트-60 감마선의 전자 오염에 관한 연구)

  • Kim, Tae-Kyu;Chun, Ha-Chung;Lee, Myung-Za
    • Radiation Oncology Journal
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    • v.7 no.2
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    • pp.293-297
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    • 1989
  • Electron contamination due to the interaction between radiation beam and material was analyzed for the factors such as source-skin distance (SSD), field size, tray characteristics and position of filter, which can affect the surface dose in Cobalt teletherapy. Surface dose in open beam was more influenced by SSD with increasing field size. Relative surface charge (RSC) increased with the use of tray (solid, circular hole, slotted), compared with open beam, which is thought to be due to increased electron contamination of the tray. To reduce the surface dose, 0.4mm thick Lipowitz metal filter was used. Compared with open beam, RSC decreased by 8.8%, 11.3%, 13.3%, 16.6%, 19.3% and 21.7% for the field size of $5{\times}5$, $10{\times}10$, $15{\times}15$, $20{\times}20$, $25{\times}25$ and $30{\times}30cm^2$, respectively. On the contrary, use of Lipowitz metal filter increased RSC at 60cm or less SSD. Surface dose was effectively reduced with Lpowitz metal filter placed right below solid tray in Cobalt teletherapy.

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Simulation of Characteristics Analysis by Total Ionizing Dose Effects in Partial Isolation Buried Channel Array Transistor (부분분리 매립 채널 어레이 트랜지스터의 총 이온화 선량 영향에 따른 특성 해석 시뮬레이션)

  • Je-won Park;Myoung-Jin Lee
    • Journal of IKEEE
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    • v.27 no.3
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    • pp.303-307
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    • 2023
  • In this paper, the creation of an Electron-Hole Pair due to Total Ionizing Dose (TID) effects inside the oxide of a Buried Channel Array Transistor (BCAT) device is induced, resulting in an increase in leakage current and threshold due to an increase in hole trap charge at the oxide interface. By comparing and simulating changes in voltage with the previously proposed Partial Isolation Buried Channel Array Transistor (Pi-BCAT) structure, the characteristics in leakage current and threshold voltage changed regardless of the increased oxide area of the Pi-BCAT device, compared to the asymmetrically doped BCAT structure. It shows superiority.

A Study on Properties of Charge & Discharge Current by Degrade in EPR (EPR의 열화에 의한 충.방전 전류 특성에 관한 연구)

  • Lee, Sung-Ill
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.7
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    • pp.679-685
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    • 2008
  • This paper describes the degraded properties of between the charge and discharge current for ${\gamma}$-ray irradiated in electric power cable rubbers using in nuclear power generating station. The charge and discharge current of degradation in EPR(Ethylene Propylene Rubber), which were irradiated with the radiant capacity of 0.033 Mrad/h, have been measured in order to investigate the influence of the atmosphere(in amount of reinforcing agent, moisture absorption and heat treatment) on electrical properties. When ${\gamma}$-ray were irradiated on the EPR with more reinforcing agent from 4 to 40 Phr, charge and discharge currents was increase due to the amount of reinforcing agent. It was verified that the discharging and charging currents irradiated by ${\gamma}$-ray were higher than those that was not irradiated. The amount of the degraded current was more after moisture absorption than before moisture absorption. The charge and discharge current after heat treatment was similar to that of before heat treatment and it was decreased with the time elapsed. As these properties related with ${\gamma}$-ray irradiation dose, it is suggested that these properties can be utilized as a index of irradiation degradation.

A Study on the Microstryctural Evoulution of the Reagion Aheas of Craters Created by Copper and W-Cu Shaped Charge Jets (W-Cu와 Cu의 고속 충돌에 의한 연강의 미세조직 변화)

  • Lee, Seong;Hong, Moon-Hee;Baek, Woon-Hyung
    • Journal of Powder Materials
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    • v.6 no.1
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    • pp.69-74
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    • 1999
  • The microstructure of the reagion of carters, created by Cu and W-Cu shaped charge jets, in a 1020 mild steel target has been intestiaged. The region ahead of the crater created by the Cu shaped charge jet, reveals dramatic grain refinement implying the occurrence of a dynamic recrystallization, while that of W-Cu one dose a martensitic transformation indicative of heating up to an austenitic region followed by rapid cooling.The impacting pressure calculated when the W-Cu shaped charge jet encounters the target is higher than that of the Cu one. The micro-hardness of the region ahead of the crater created by the W-Cu shaped charge jet is also higher than that of the Cu one. The microstructure of W-Cu slug remained in the inside of the craters depicts the occurrence of the remarkable elongation of W particles during the liner collaphse. From these results, the microstructural variation of the region ahead of the crater with Cu and W-Cu shaped charge jets is discussed in trems of the pressure dependency of the transformation region of ferrite and austenite phases.

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Real-time monitoring of ultra-high dose rate electron beams using bremsstrahlung photons

  • Hyun Kim;Dong Hyeok Jeong;Sang Koo Kang;Manwoo Lee;Heuijin Lim;Sang Jin Lee;Kyoung Won Jang
    • Nuclear Engineering and Technology
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    • v.55 no.9
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    • pp.3417-3422
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    • 2023
  • Recently, as the clinically positive biological effects of ultra-high dose rate (UHDR) radiation beams have been revealed, interest in flash radiation therapy has increased. Generally, FLASH preclinical experiments are performed using UHDR electron beams generated by linear accelerators. Real-time monitoring of UHDR beams is required to deliver the correct dose to a sample. However, it is difficult to use typical transmission-type ionization chambers for primary beam monitoring because there is no suitable electrometer capable of reading high pulsed currents, and collection efficiency is drastically reduced in pulsed radiation beams with ultra-high doses. In this study, a monitoring method using bremsstrahlung photons generated by irradiation devices and a water phantom was proposed. Charges collected in an ionization chamber located at the back of a water phantom were analyzed using the bremsstrahlung tail on electron depth dose curves obtained using radiochromic films. The dose conversion factor for converting a monitored charge into a delivered dose was determined analytically for the Advanced Markus® chamber and compared with experimentally determined values. It is anticipated that the method proposed in this study can be useful for monitoring sample doses in UHDR electron beam irradiation.

Chemical Coagulation Conditions and Efficiency of Sewage with Al(III) and Fe(III) Coagulants (하수의 화학적 응집조건 및 응집제별 응집효율 분석)

  • Park, June-Gue;Tian, Dong-Jie;Park, Noh-Back;Jun, Hang-Bae
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.4
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    • pp.463-474
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    • 2010
  • In this study, chemical coagulation conditions for treating combined sewer overflow(CSO) occurred during rainy season were evaluated by jar tests with aluminum sulfate[$Al_2(SO_4)_3{\cdot}17H_2O$] and ferric chloride[$FeCl_3{\cdot}6H_2O$]. The raw domestic sewage sampled from the primary sedimentation tank at a local sewage treatment plant was filtered through $150{\mu}m$ sieve before using. Point of zero charge(PZC) for various dose of aluminum sulfate occurred at pH 5.8-6.5, while for ferric chloride occurred at pH 5.3-6.0 in term of streaming current(SC) values. Charge neutralization ability of aluminum sulfate was bigger than that of ferric chloride. Optimum pH and dose of aluminum sulfate and ferric chloride were 6.2, 0.438mM and 5.8, 0.925mM, respectively. Removal efficiencies of TCOD, turbidity, SS and TP were 75, 97, 95, 96% with aluminum sulfate and 74, 96, 98, 99% with ferric chloride at their optimum coagulation conditions. More efficient removal of SS, TP and small particles was possible with ferric chloride at optimum coagulation conditions. Both SC values and COD removal started to increase where soluble phosphorus was completely removed.

Radiation-hardened-by-design preamplifier with binary weighted current source for radiation detector

  • Minuk Seung;Jong-Gyun Choi ;Woo-young Choi;Inyong Kwon
    • Nuclear Engineering and Technology
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    • v.56 no.1
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    • pp.189-194
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    • 2024
  • This paper presents a radiation-hardened-by-design preamplifier that utilizes a self-compensation technique with a charge-sensitive amplifier (CSA) and replica for total ionizing dose (TID) effects. The CSA consists of an operational amplifier (OPAMP) with a 6-bit binary weighted current source (BWCS) and feedback network. The replica circuit is utilized to compensate for the TID effects of the CSA. Two comparators can detect the operating point of the replica OPAMP and generate appropriate signals to control the switches of the BWCS. The proposed preamplifier was fabricated using a general-purpose complementary metal-oxide-silicon field effect transistor 0.18 ㎛ process and verified through a test up to 230 kGy (SiO2) at a rate of 10.46 kGy (SiO2)/h. The code of the BWCS control circuit varied with the total radiation dose. During the verification test, the initial value of the digital code was 39, and a final value of 30 was observed. Furthermore, the preamplifier output exhibited a maximum variation error of 2.39%, while the maximum rise-time error was 1.96%. A minimum signal-to-noise ratio of 49.64 dB was measured.