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Hyojeong Choi(Hyojeong Choi),Sanggyun Roh(Sanggyun Roh) 한국화재소방학회 2022 International Journal of Fire Science and Engineer Vol.36 No.3
This study aimed to analyze the characteristics of out-of-hospital acute cardiac arrest patients collected from the Korea Centers for Disease Control and Prevention to identify the current status and provide basic data to increase the recovery rate of out-hospital acute cardiac arrest patients. As a result of the study, the number of acute cardiac arrest patients in Korea in 2019 was 30,279, of whom 1,505 (64.4%) were men and 10,774 (35.6%) were women. Of the total patients, 1,056 (51.7%) showed good neurological outcomes when paramedics performed defibrillation at the pre-hospital stage (p = 0.001). In the initial review of electrocardiographic rhythm performed by paramedics, 1,025 patients (52.8%) showed ventricular fibrillation and pulseless ventricular tachycardia, which indicated good neurological outcomes (p = 0.001).
Design and Optimization of an Analog Filter with a CdTe Detector for X-ray Fluorescence Applications
Hyojeong Choi,Hui Su Kim,Young Soo Kim,Jang Ho Ha,Jong-Seo Chai 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.7
An analog pre-filter circuit for digital pulse processing is designed and optimized for X-ray fluorescence (XRF) applications to replace traditional analog shaping amplifiers. To optimize the pre-filter performance, we characterized noise electrons as a function of the input pulse rise time and decay time of the output pulse by using the full width at half maximum. In addition, gamma-ray energy measurements at room temperature showed that the commercially available CdTe Schottky-type radiation detector with our newly designed and optimized pre-filter circuit exhibited full widths at half maxima of 4.97 (Ba-133, at 53 keV) and 5.56 keV (Am-241, at 59.5 keV), respectively.
Design and Optimization of an X-ray Detector Module for Air-Cargo Inspection
Choi Hyojeong,Park Jeong Min,Kang Chang Goo,Kim Su Jin,김병혁,Mun Jungho,Kim Han Soo,Lee Nam-Ho,Kim Young Soo 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.12
In this study, we developed an X-ray detector module (XDM) that includes two readout electronic units and a 64-channel data acquisition system for X-ray imaging systems. The readout electronic unit comprises eight X-ray sensor arrays (two CdWO4 scintillators and four Si-PIN photodiodes per detector array), 32 charge integrators, 32 sample-and-holds (S/H), 4 shift registers, and a buffer. The data acquisition system comprises line drivers and receivers, a multiplexer, an analog-to-digital converter, and a 32-kB static random-access memory. All the control signals for module operation are implemented in a field-programmable gate array. The module operates with a single 24 V DC supply and transfers each channel's data to the host computer through an Ethernet port. We fabricated a 64-channel electronic module and evaluated its performance in terms of the relative offset and linearity. By connecting 14 XDMs, air-cargo container images were successfully acquired through X-ray irradiation at an energy of 6-MeV.
FPGA-based trapezoidal digital pulse shaping in nuclear spectrometry
Choi Hyojeong,Chai Jong-Seo 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.3
A digital pulse processing is most widely used in nuclear spectrometry for achieving good energy resolution at high count rates. We developed a digital pulse processing system to implement a peak detection algorithm using digital trapezoidal pulse shaping. The incident radiation signal amplifed by the preamplifer is converted into digital data through the preflter and the analog-to-digital converter; then, this signal is shaped into trapezoidal pulses through the implemented algorithm which consists of rising edge detection, pile-up signal discrimination and ofset remove, two stages of convolutions, peak detection and ballistic defcit discrimination. We compared a linearity of the system between simulation and experimental results. The noise was calculated using a commercial test input pulser, and then, the 59.5 keV of gamma-ray spectrum with CdTe Schottky detector was obtained using an Am-241 radioisotope source. This system showed better noise characteristics and gamma-ray spectroscopy characteristics than existing commercial analog systems.