• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.765-766
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.767-768
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• 2005

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.275-279
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• 2001

In uranium enrichment plants and nuclear fuel fabrication facilities, exact measurement of fissile isotope enrichment of uranium is required for material accounting in international safeguards inspection as well as process quality control. The purpose of this study was to develop a simple measurement system which can portably be used at nuclear fuel fabrication plants especially dealing with low enriched uranium. For this purpose, a small size CZT (CdZnTe) detector was used, and the detector performance in low uranium gamma/X -rays energy range was investigated by use of various enriched uranium oxide samples. New enrichment measurement technique and analysis method for low enriched uranium oxide, so-called, 'semi-peak ratio technique' was developed. The newly developed method was considered as an alternative technique for the low enrichment and would be useful to account nuclear material in safeguarding activity at nuclear fuel fabrication facility.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.379-381
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• 2002

A single CdZnTe detector is tested for suitability in a prototype CT/ SPECT system designed to acquire both emission and transmission data. The detector has the size of 1${\times}$l-cm$^2$ with 4${\times}$4 1.5${\times}$l.5mm$^2$ pixellated anodes. Since the detector is smaller than imaged object, we translated it in an arc centered at the x-ray tube to image larger objects. Pulse counting electronics with very short shaping time (50 ns) are used to satisfy high photon rates in x-ray imaging, and response linearity up to 3${\times}$10$\^$5/ counts per second per detector element is achieved. The energy resolution of 122-keV gamma-ray is measured to be 14%. We have characterized the system performance by scanning a radiographic resolution phantom .and the Hoffman brain phantom. The spatial resolution of CT and SPECT are about 1 mm and 7 mm, respectively.

• Journal of Radiation Industry
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• v.5 no.1
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• pp.95-99
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• 2011

The electrical and mechanical properties of electrode for radiation detection are very important. In general, Au electrode and CZT crystal are combined to form ohmic contacts, and the best energy resolution is shown at the Au electrode. The metal contacts are fabricated by electroless deposition method, sputtering deposition method and thermal evaporation method. The electrode fabrication is easy with use of the thermal evaporation method, while an adhesive strength is weak. Thus interface materials such as Ag, Al and Ni were investigated to overcome defects generated by the this method. The thickness of the interface material between the Au electrode and the CZT crystal was 100 Angstroms, the Au electrode with thickness of 400 Angstroms was deposited. The Al+Au electrode is shown that the results of current-voltage and radiation response are similar to results of Au electrode.

• Journal of Radiation Protection and Research
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• v.47 no.1
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• pp.39-49
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• 2022

Background: For proper monitoring of the eye lens dose, an appropriate calibration factor of a dosimeter and information about the mean energies of X-rays are indispensable. The scattered X-ray energy spectra should be well characterized in medical practices where eye lenses of medical staffs might be high. Materials and Methods: Scattered X-ray energy spectra were experimentally derived for three different types of X-ray diagnostic and therapeutic equipment, i.e., the computed tomography (CT) scan, the angiography and the fluoroscopy. A commercially available CdZnTe (CZT) spectrometer with a lead collimator was employed for the measurement of scattered X-rays, which was performed in the usual manner. Results and Discussion: From the obtained energy spectra, the mean energies of the scattered X-rays lied between 40 and 60 keV. This also agreed with that obtained by the conventional half value layer method. Conclusion: The scattered X-rays to which medical workers may be exposed in the region around the eyes were characterized by means of spectrometry. The obtained mean energies of the scattered X-rays were found to match the flat region of the dosimeter response.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1031-1035
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• 2023

Neutron is an indirectly ionizing particle without charge, which is normally measured by detecting reaction products. Neutron detection system based on measuring gadolinium-converted gamma-rays is a good way to monitor the neutron because the representative prompt gamma-rays of gadolinium have low energies (79, 89, 182, and 199 keV). Low energy gamma-rays and their high attenuation coefficient on materials allow the simple design of a detector easier to manufacture. Thus, we designed a cadmium zinc telluride detector to investigate feasibility of simultaneous detection of gamma-rays and neutrons by using the Monte-Carlo simulation, which was divided into two parts; first was gamma-detection part and second was gamma- and neutron-simultaneous detection part. Consequently, we confirmed that simultaneous detection of gamma-rays and neutrons could be feasible and valid, although further research is needed for adoption on real detection.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.197-202
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• 2022

The CZTS solar cell is a thin film solar cell using an absorption layer composed of Cu, Zn, Sn, Se, and S, and is cheaper than a CIGS solar cell using In and Ga and more eco-friendly than a perovskite and CdTe solar cell using Pb and Cd. In this study, we conducted a bending test for flexible CZTS solar cells. Experiments were conducted in the direction of inner benidng with compressive stress and outer bending with tensile stress, and during the number of bending 1,000 times with a radius of curvature of 50 mmR, the efficiency of the solar cell decreased by up to 12.7%, and the biggest cause of efficiency reduction in both directions was a large decrease in parallel resistance.

• Korean Journal of Materials Research
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• v.32 no.11
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• pp.481-488
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• 2022

The Cu₂ZnSn(S_xSe_1-x)₄ (CZTSSe) absorbers are promising thin film solar cells (TFSCs) materials, to replace existing Cu(In,Ga)Se₂ (CIGS) and CdTe photovoltaic technology. However, the best reported efficiency for a CZTSSe device, of 13.6 %, is still too low for commercial use. Recently, partially replacing the Zn²⁺ element with a Cd²⁺element has attracting attention as one of the promising strategies for improving the photovoltaic characteristics of the CZTSSe TFSCs. Cd²⁺ elements are known to improve the grain size of the CZTSSe absorber thin films and improve optoelectronic properties by suppressing potential defects, causing short-circuit current (J_sc) loss. In this study, the structural, compositional, and morphological characteristics of CZTSSe and CZCTSSe thin films were investigated using X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), and Field-emission scanning electron microscopy (FE-SEM), respectively. The FE-SEM images revealed that the grain size improved with increasing Cd²⁺ alloying in the CZTSSe thin films. Moreover, there was a slight decrease in small grain distribution as well as voids near the CZTSSe/Mo interface after Cd²⁺ alloying. The solar cells prepared using the most promising CZTSSe absorber thin films with Cd²⁺ alloying (8 min. 30 sec.) exhibited a power conversion efficiency (PCE) of 9.33 %, J_sc of 34.0 mA/cm², and fill factor (FF) of 62.7 %, respectively.

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.392-396
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• 1999