• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.2
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• pp.97-104
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• 2004

Neutron induced prompt gamma-ray spectroscopy(NIPS) system measures the prompt gamma-ray emitting by the interaction of a neutron with various materials. This system will be of great benefit to scientists worldwide, since it provides the non-destructive measurement of many element in either solid or liquid wastes. In this study, the full-energy-peak (FEP) efficiency calibration for a HPGe detector was constructed in the ${\gamma}$-ray energy range from 80 keV to 8 MeV, using $^{l33}$Ba and >TEX>$^{152}Eu$ RI sources and $ ^{35}Cl(n, ${\gamma}$)^{36}Cl$ thermal neutron captured reaction. The FEP efficiency curve for the higher energies using the $^{35}Cl(n, ${\gamma}$)^{36}Cl$ reaction was normalized with the curve obtained from the RI sources, since the accurate activity of its prompt ${\gamma}$-ray is unknown. The average thermal neutron flux was theoretically calculated using the FEP efficiency curve for the KCl standard solutions. The NIPS system equipped with a ${\gamma}$-${\gamma}$ coincidence setup with two n-type coaxial HPGe detectors was considered in order to reduce the interfering ${\gamma}$-ray background. The FEP efficiency curve for the ${\gamma}$-${\gamma}$ coincidence system was also obtained for full energy range. The performance of the normal and coincidence NIPS system was tested by comparing signal-to-noise ratio in each mode using the reference sample.e.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.73-77
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• 2010

In recent day, there is much interest in the biocidal activity of silver since silver is known to be safe and effective as disinifectant and biocidal material against coliforms and viruses. In this study, hydrogels containing silver acetate as antibacterial agent have been prepared using gamma rays irradiation. The hydrogels are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG), carrageenan and silver acetate. The concentration of solution was 9 wt%. The ratio of PVP : PEG : carrageenan was 6 : 1 : 2. The concentration of the silver acetate were 0, 0.01, 0.03, 0.05 and 0.07% and Gamma irradiation dose was 25 kGy. The Gamma irradiation dose in hydrogels with 0.01% silver acetate were 20 kGy, 35 kGy, 50 kGy, 65 kGy, and 80 kGy. The results showed that 0.01% silver acetate concentration of hydrogels by 25 kGy irradiation dose showed the highest antibacterial activity against E. coli and Staphylococcus aureus. Moreover, antibacterial activity of various Gamma irradiation dose in hydrogels treated 0.01% silver acetate showed highest 35 kGy irradiation dose against Staphylococcus aureus.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.183-190
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• 2001

The activity concentration of primordial radionuclides i.e., $^{238}U$ series, $^{232}Th$ series and $^{40}K$, in soil samples collected from Udagamandalam environment, have been measured by employing NaI (Tl) Gamma ray Spectrometer. The absorbed gamma dose rate has also been simultaneously measured by using both Environmental Radiation Dosimeter at each soil sampling location (ambient gamma dose) as well as from the gamma dose derived from the activity concentration of the primordial radionuclides. The results of activity concentration of each radio nuclides in soil, absorbed dose rate in air due to soil activity and possible cosmic radiation at each location along with human effective dose equivalent for Udagamandalam environment are presented and discussed.

• Journal of The Korean Astronomical Society
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• v.50 no.6
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• pp.167-178
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• 2017

We present a study of the inexplicit connection between radio jet activity and ${\gamma}$-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two ${\gamma}$-ray outbursts (in November 2013 and March 2015) can be seen in ${\gamma}$-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of $411{\pm}85$ days, $352{\pm}79$ days, $310{\pm}57$ days, and $283{\pm}55$ days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths $B{\sim}2{\mu}T$ and electron Lorentz factors ${\gamma}$ ~ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we find that the decay timescale ${\tau}$ scales with frequency ${\nu}$ like ${\tau}{\propto}{\nu}^{-0.2}$. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the ${\gamma}$-ray outbursts. The spectral evolution is consistent with the 'generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second ${\gamma}$-ray event indicate that this ${\gamma}$-ray outburst might be an 'orphan' flare powered by the 'ring of fire' mechanism.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.429-438
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• 2014

This study was designed to investigate the effects on anti-oxidative activities and increasing extraction yield of Aralia elata Cortex by gamma irradiation. Electron spin resonance (ESR) analysis as physical techniques for irradiation identification of Aralia elata showed that a pair of peak appeared on a space of 6.0 mT at the left and right of symmetric unspecific central ESR spectrums, confirming that the plant was gamma-irradiated. The optimum extracting conditions for preparing gamma irradiated samples from Aralia elata Cortex were to extract with 50% ethanol for 15 hrs after 10 kGy irradiation. DPPH scavenging activity and ABTS radical cation inhibitory activity of the water and 50% ethanol extracts from non irradiated and irradiated Aralia elata Cortex was very high as over 80% and 98%, respectively, at tested low concentration of $50{\mu}g/mL$. Antioxidant protection factor (PF) as anti-oxidation indicator of lipophilic compounds showed a very high level of activity as 2.18~2.78 PF. As for TBARs, water and ethanol extracts showed high level. Increase of TBARs inhibitory activity of water extracts was not shown by gamma-ray irradiation but ethanol extracts showed slight increasement of TBARs inhibitory activity with 10 kGy gamma-ray irradiation. These results shown confirmed increasement of extraction yield for phenolic compounds and anti-oxidative activity from Aralia elata. Thus, the treatment of gamma-irradiation can be used a way to amplify a solubility for biological active compounds and anti-oxidative activity in plants.

• Nuclear Engineering and Technology
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• v.11 no.2
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• pp.105-110
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• 1979

In order to evaluate the effect of gamma ray irradiation to the soils added with several organic matters on release sad fixation of $^{65}Zn$, a soil incubation test was carried out by use of an acidic and a calcareous soil. The results obtained were summarized as follows : DTPA extractable $^{65}Zn$ decreased gradually with elapsed time of incubation owing to fixation of $^{65}$Zn by the soils but after four weeks DTPA extractable $^{65}Zn$ was reached an equilibrium state. The most parts of $^{65}Zn$ activity in the equilibrium state was found in the solid phase. The extent of zinc fixation in acidic Keumgok and calcareous Jecheon soils represented as activity basis was 89 and 93.7 per cent of applied $^{65}Zn$ respectively. Increased tendency of DTPA extractable zinc was shown by irradiating gamma ray to both soils because of $^{65}Zn$ fixation could be decreased by irradiation. The extractability of fixed $^{65}Zn$ by DTPA solution was 38.9 per cent in acidic Keumgok soil and only 9.5 per cent in calcareous Jecheon soil. Release of fixed $^{65}Zn$ by irradiation of gamma ray is closely related to pH of both soils. Much more $^{65}Zn$ could be released under low pH condition. Effect of gamma ray irradiation to organic matter sources on release of $^{65}Zn$ could not be differentiated. But in the case of nonirradiated soils, however, glucose treated soils couldrelease much more the extractable zinc as compared to those of the straw or cellulose treatment.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.464-469
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• 1998

A coincidence gamma-ray spectroscopy method was applied to reduce the background radioactivity for measuring the activity of radioisotopes in a sample in the presence of environmental natural radioactivity. A HPGe detector was used for the coincident spectrum as a main detector and a NaI(Tl) scintillation detector for gating purposes as an associated detector. For coincidence spectroscopy the whole energy spectrum of associated detector was used instead of gate signals. The coincident events obtained from the gating spectrum was evaluated by a coincidence computer program in this study instead of timing circuit. In this work, the background of detection environment was reduced to factor 100 and peaks to be determined was reduced to factor 30 using the coincidence gamma-ray spectroscopy.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1754-1759
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• 2022

The activity of gamma-ray emitting nuclides is calculated assuming that each gamma-ray is detected individually; thus, the magnitude of the coincidence summing signal must be considered during activity calculations. Here, the correction factor for the coincidence summing effect was calculated, and the detection efficiencies of two HPGe detectors were compared. The CANBERRA Inc. GC4018 high-purity Ge detector provided an estimate for the peak-to-total ratio using a point source to determine the coincidence summing correction factor. The ORTEC Inc. GEM60 high-purity Ge detector uses EFFTRAN in LVis to obtain the parameters of the detector and source model and the gamma-gamma and gamma-X match estimates, in order to determine the coincidence summing correction factor. Nuclide analyses, radioactivity comparisons, and analyses of reference material samples were performed utilizing certified reference materials to accurately determine the detection efficiencies. For both Co-60 and Y-88, the detection efficiency for a point source increased by an average of at least 12-13%, whereas the detection efficiency determined using LVis increased by an average of at least 13-15%. The calculated radioactivity values of the certified reference material and reference material samples were accurate to within 3% and 6% of the measured values, respectively.

• Korean Journal of Veterinary Research
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• v.55 no.1
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• pp.21-30
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• 2015

The immune system is specifically sensitive to oxidative stress induced by ionizing radiation because of its rapid proliferative activity. For this reason, an instructive immune system is one of the best ways to minimize side effects, such immunodeficiency, of gamma radiation. Over the past few decades, several natural plants with antioxidant and immunomodulatory properties have been identified as adjuncts for nontoxic and successful radiotherapy. Hizikia fusiforme extract (HFE) containing plentiful dietary fiber and fucoidan is known for its instructive antioxidant capacity, immunomodulation abilities, and immune activation. In this study, we determined whether HFE protects radiosensitive immune cells from gamma radiation-induced damage. C57BL/6 mice were irradiated with gamma-ray. The effect of HFE on the ionizing radiation damage of immune cells was then evaluated with an MTT assay, 3H-thymidine incorporation assay, and PI staining. We found that HFE stimulated the proliferation of gamma-ray irradiated immune cells without cytotoxic effects. We also observed that HFE not only decreased DNA damage but also reduced gamma radiation-induced apoptosis of the immune cells. Our results suggest that HFE can protect immune cells from gamma-ray damage and may serve as an effective, non-toxic radioprotective agent.

• The Korean Journal of Mycology
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• v.40 no.2
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• pp.93-97
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• 2012

Gamma ray irradiation mutagenesis was employed to get variants of Pleurotus eryngii with functionally enhanced and improved characteristics. Protoplasts released from P. eryngii were treated with gamma ray radiation under 0.25-1.25 KGy. Protoplast sample that showed fatality rate of 80% at the 0.25 KGy was spreaded on YPMGA (yeast, peptone, malt-extract, glucose, agar) and 500 mycelial colonies were randomly selected from the medium. Of them, 100 mutant strains with mycelial morphology and growth rate that differ to control strain were observed on PDA. The cellulase and laccase activity of 67 gamma ray-irradiated P. eryngii isolates with morphological variation were investigated. Among these, 5 isolates were higher cellulase. In addition, the genetic variation of the mutant strains was analyzed by PCR fingerprinting.