• Nuclear Engineering and Technology
• /
• v.26 no.3
• /
• pp.381-388
• /
• 1994

Recently, the American National Standards Institute (ANSI) had made some changes in the radiation sources specified from those in the original performance test criteria ANSI N13. 11-1983. In case or beta category, in addition to the high-energy $^{90}$ Sr/$^{90}$ Y beta source, the $^{204}$ Tl source was added because many workplaces have significant levels of lower energy betas. In this study, the performance or the Teledyne PB-3 personnel dosimetry system in the fields of $^{204}$ Tl and $^{90}$ Sr/ $^{90}$ Y beta was investigated using the PTB beta secondary standard sources. The new beta correction function of PB-3 personnel dosimetry system for $^{204}$ Tl beta was also developed in this response experiment. The results show that the Teledyne PB-3 personnel dosimetry system is very effective for $^{90}$ Sr/ $^{90}$ Y beta dose assessment. In case of $^{204}$ Tl beta radiation, however, the results of simple performance test indicated that the use of beta correction factor(=2.088) which was recommanded by manufacturer may result in unexpectable overestimation of delivered dose by about 60%, while the use of developed beta correction function could measure the delivered doses in errors of 15%.

• Journal of Radiation Protection and Research
• /
• v.21 no.4
• /
• pp.263-271
• /
• 1996

The ANSI N13.32 recommends that a study of the angular response of a dosimeter be carried out once, although no pass/fail criterion is given for angular response. Gamma dose equivalent conversion and angular dependence factors were calculated by using MCNP code for the case of ANSI N13.32 extremity phantoms(finger and arm) at the depth of $7mg/cm^2$. Those extremity dosimeters were assumed to be irradiated from both monoenergitic photons and ISO X-ray narrow beams. These calculated gamma dose equivalent conversion and angular dependence factors were compared to B. Grosswendt's result calculated by using X-ray beams. The result showed that the dose equivalent conversion factors of this study agreed well with that of B. Grosswendt for all energies within 2% except 7% in the case of the low energies. In the case of angular dependence factors comparison, they agreed within 3%. It was shown that angular dependence factors of the finger phantom decreased as the horizontal angle of the phantom increased for the ISO X-ray beams less than 60keV. For the higher energy X-ray beams range they decreased slightly around 40 degree, but then increased from this energy to 90 degree.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.19 no.5
• /
• pp.356-362
• /
• 1999

Based on the assumption that film density increases exponentially with exposure in the industrial radiographic film. an equation representing the characteristic curves of industrial radiographic films and a new density-thickness relation are suggested. The accuracy and reliability of the suggested relation has been tested using radiographs of a carbon steel step wedge with known thickness variation by polychromatic X-ray and ${\gamma}$-ray ($Ir^{192}$). The experimental results were well agreed to the proposed relation in the range of film densities from 1.0 to 3.5 and it was more accurate than the conventional relation. It is also found that ${\gamma}$-ray is more effective in this purpose than polychromatic X-ray, which results in variation of effective linear absorption coefficient due to beam hardening effect as thickness increases. Therefore using the equation and experimentally determined parameters the quantitative evaluation of thickness variation is possible and it can be used to evaluate the depth of local corrosion of pressure vessels in plants.

• Journal of Radiation Protection and Research
• /
• v.36 no.2
• /
• pp.79-85
• /
• 2011

OThe purpose of this article was to measure and compare the value of the metal artifact reduction (MAR) algorithm by Dual energy(kVp switching) CT (Computed Tomography) for non using MAR and we introduced new variable Dual energy CT applications through a clinical scan. The used equipment was GE Discovery 750HD with Dual-Energy system(kVp switching). CT scan was performed on the neck and abdomen area subject for patients. Studies were from Dec 20 2010 to Feb 10 2011 and included 25 subject patients with prosthesis. We were measured the HU (Hounsfield Unit) and noise value at metal artifact appear(focal loss of signal and white streak artifact area) according to the using MAR algorithm. Statistical analyses were performed using the paired sample t-test. In patient subject case, the statistical difference of showing HU was p=0.01 and p=0.04 respectively. At maximum black hole artifact area and white streak artifact area according to the using MAR algorithm. However noise was p=0.05 and p=0.04 respectively; and not the affected black hole and white streak artifact area. Dual Energy CT with the MAR algorithm technique is useful reduce metal artifacts and could improve the diagnostic value in the diagnostic image evaluation of metallic implants area.

• Korean Journal of Food Science and Technology
• /
• v.46 no.2
• /
• pp.256-261
• /
• 2014

This study was conducted to determine the effect of gamma-ray and electron-beam irradiation on dried spices (black pepper, red pepper, parsley, and basil) using the photostimulated luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) methods. The spices were irradiated at 0, 1, 5, and 10 kGy. All non-irradiated spices had photon counts (PCs) less than 700 PCs. The PCs of three irradiated spices (red pepper, parsley, and basil) were clearly distinguishable from those of non-irradiated ones, exhibiting PSL signals higher than 5000 PCs. However, negative PSL counts (<700 PCs) were obtained for most irradiated black pepper, except those irradiated with 5 kGy gamma rays and 10 kGy electron-beams. TL glow curves of the irradiated spices showed a higher peak at $150-250^{\circ}C$. TL ratios were found to be less than 0.1 for non-irradiated spices and higher than 0.1 for irradiated ones. No ESR signal was observed for any irradiated spice except red pepper, which displayed cellulose-based ESR spectra. Therefore, the results suggest that the PSL, TL, and ESR methods are effective detection techniques for dried spices irradiated with electron beams as well as gamma rays.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5465-5470
• /
• 2012

FPGA(Field Programmable Gate Array) devices are widely used due to their merits in circuit development time, and development cost. Among various FPGA technologies, SRAM-based FPGAs have large cell capacity so that they are attractive for complex circuit design and their reconfigurability. However, they are weak in space environment where radiation energy particles cause Single Event Upset(SEU). In this paper, we designed a controller supervising SRAM-based FPGA to protect configuration memory inside. The controller is implemented on an Anti-Fusing FPGA. Radiation test was performed on the implemented computer board and the result show that our controller provides better SEU-resilience than TMR-only system.

• Korean Journal of Food Science and Technology
• /
• v.20 no.6
• /
• pp.737-741
• /
• 1988

The storage stabilities of philipines' bananas were investigated according to the storage pretreatments and packaging methods during 60 days storage at $13^{\circ}C$. The better storage stability was got in bananas packaged with 60{\mu}m low density polyethylene (PE) film inside the carton box than those without inside pack. Radiation gave the adverse effects on bananas' storage stabilities. Shelf-life of bananas in PE package was 60 days, but that of radiated bananas was only 20 days. And shelf-life of bananas in no inner pack was 20 days. Soluble solid content of bananas packaged with PE film was 17 Brix degree after 60 days storage, but that with no inner package was around 20 Brix after 20 days. Color was below 3 in color chart after 60 days storage and hardness was rapidly decreased from 40 days in bananas packaged with PE film, but color was became to 3 color after 30 days and hardness was rapidly decreased after 20 days in bananas without inner package. Percentage of deteriorated bananas were below 3% in PE films after 60 days storage, but 100% after 40 days in bananas without inner package.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.1
• /
• pp.66-69
• /
• 1999

To investigate the hormetic effect of the low dose ${\gamma}-ray$, soybean(Glycine max L.) seeds of three cultivars (Hwangkeumkong, Bansakong, S900 cv.) were irradiated with the dose of 0.5∼20.0 Gy and cultivated in the experimental field. The hormetic effects of the low dose ${\gamma}-ray$ on the growth of field experiment were different from each cultivar, that is, more effective in the S900 cultivar of black seedcoat color than in the Hwangkeumkong and Bangsakong of yellow ones. The germination rate of S900 cultivar increased about 30% in the 0.5Gy irradiated group compared with that of the control. The plant height of the 4.0Gy irradiated group in both Bangsakong and S900 cultivar increased 15% more than that of the control. Grain yield and the number of pod in 1.0 Gy and 4.0 Gy irradiated group of S900 cultivar and that of 2.0 Gy irradiated group of Hwangkeumkong increased 25 and 35% on the average, respectively.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.6 no.3
• /
• pp.233-244
• /
• 2008

A conceptual design study for a pyroprocesing facility, has been carried out in this study, which is available for the recovery of uranium and transuranic elemental group(TRU), that is, reusable as a nuclear fuel especially in a next generation-type reactor. The scale of this facility has been chosen as 20 kg HM/batch, comparatively small engineering size in order to collect scale-up data for the design of a commercial facility as well as to get operational experience. The spent fuel to be handled in this process is as follows : 3.5 % enriched uranium fuel, 35,000MWd/tU and 5-year cooled. The major items considered in the conceptual study are a building lay-out including various hot cells, safety management of the process operation in conjunction with material balance control, radiation safety, inert atmosphere control in shielded hot cells, and criticality control of uranium and TRU products.

• Nuclear Engineering and Technology
• /
• v.1 no.1
• /
• pp.23-31
• /
• 1969

Whole cure shrimp, eviscerated common squid and little squid meats were irradiated with gamma radiation from 60Co using varying dose up to one Mrad. Changes in quality were assessed by organoleptic, chemical (VRS and TMA-N), biochemical (hypoxanthine) and microbiological tests； and the effect of radiation on prolonging of the storage life at 2-4 C was studied. With the cure shrimp, 0.12-0.20 Mrad appears to be optimal with 8 days of storage life, whereas the unirradiated control samples had a storage life of 3 days. With the common squid meat, 0.20-0.30 Mrad appears to be optimal with 14-21 days of storage life, where-as the unirradiated control samples had a storage life of 8 days. And for the little squid meat, 0.12-0.20 Mrad appears to be optimal with 10 days of storage, where-as the unirradiated control samples had a storage life of 5 to 6 days.