Effects Of Gamma-ray Irradiation Research Articles

Effects of Low-Dose Gamma-Ray Radiation on Apoptosis and Development of Zebrafish Embryo Brain.

To investigate the effects of low-dose γ irradiation on apoptosis and development of the brain in zebrafish embryos, cumulative 15 mGy doses of γ rays from a 137Cs source were used to irradiate zebrafish embryos at 2 h post-fertilization (hpf) for 120 h. Apoptosis of the brain, brain morphological development, cell submicroscopic structure and mRNA expression were analyzed, respectively. Results indicate that after 15 mGy exposure, the apoptosis of zebrafish brain increased, vacuoles appeared in brain tissue, some organelles were damaged and vacuoles appeared locally in brain cells. The mRNA expression level of axin2 was significantly upregulated, and those of frizzled, β-catenin, camk2, TCF/ LEF and bcl9 were significantly downregulated in brain tissue. These genes are involved in the Wnt signaling pathway. The findings of this work suggest that low-dose radiation may influence the apoptosis and development of the brain in the zebrafish embryo by inhibiting the Wnt signaling pathway.

Gamma-ray irradiation induced variation in charge transport behavior of polyethylene based boron nitride/silica micro/nanocomposites

This paper examines the effect of Co60 gamma-ray irradiation to a maximum total dose of 1000 kGy on the charge transport in polyethylene based micro/nanocomposites. Micron sized hexagonal boron nitride (BN) and nano size silica (SiO 2 ) fillers are used in this work. Surface potential decay measurement are used to evaluate the charge transport in the composite samples. Scanning electron microscopy, Fourier transform infrared spectrum, differential scanning calorimetry, and gel content techniques are used to understand the irradiation induced variations in the microstructure of the composites. The results indicate that the carrier trap center becomes shallower and the carrier mobility tends to increase with increasing gamma ray dose and this effect is mitigated with the addition of fillers. It is suggested that the radiation induced reduction in the crystallinity and the appearance of voids and the formation of carbonyl groups are responsible for the observed effect. The micron- and the nano-size particles hinder the penetration of oxygen, thereby reducing oxidation, and the gamma-ray irradiation induces increased charge transport in the composites.

Quantitative Measurement of \u03b3-Ray and e-Beam Effects on Fiber Rayleigh Scattering Coefficient

The effects of gamma ray (γ-ray) radiation and electron beam (e-beam) radiation on Rayleigh scattering coefficient in single-mode fiber are experimentally investigated. Utilizing an optical time domain reflectometry (OTDR), the power distribution curves of the irradiated fibers are obtained to retrieve the corresponding radiation-induced attenuation (RIA). Based on the backscattering power levels and the measured RIAs, the Rayleigh scattering coefficients can be characterized quantitatively for each fiber sample. Under the given radiation conditions, Rayleigh scattering coefficients have been changed very little while RIAs have been changed significantly. Furthermore, simulations have been implemented to verify the validity of the measured Rayleigh scattering coefficient, including the splicing points.

Gamma-ray irradiation effects on tantalum thin film for improved mechanical compatibility and cytocompatibility.

In this work, tantalum thin films were prepared on titanium substrates by an ion beam sputtering method. Tantalum thin films were irradiated by gamma-ray with different total dose levels. The effect of irradiation on the phase composition, microstructure, surface morphology, and chemical resistance were analyzed. Besides, in vitro cytocompatibility of tantalum films treated with different radiation doses were evaluated via 3T3-E1 cells. Experimental results showed that higher radiation dose resulted in reductions in crystalline nature, denser morphology, lower elastic modulus, less oxygen vacancies and better corrosion resistance. Additionally, 3T3-E1 cells adhered and spread well on the surface of tantalum film with irradiation exposure to 10kGy. The dense surface morphology, less density of chemical defects and amorphous phase produced by the gamma-ray irradiation played a major role in the improvement of mechanical compatibility, electrochemical stability property along with the cytocompatibility of the tantalum films.

Effect of gamma rays on phenotypic of garlic cultivar doulu

This research aims to determine the effect of gamma-ray irradiation on the phenotypic of the garlic cultivar Doulu. The study was conducted in April-August 2018. Radiation on the bulb garlic is carried out at the centre of Safety and Meteorological Technology (PTKMR), BATAN, Jalan Lebak bulus Raya No. 49 Jakarta. Bulb planting is done at the research Hall of vegetable crops, Tongkoh village, Berastagi, North Sumatera. The draft used in this study is non factorial group random draft with 6 radiation dose treatment of 0 Gy (Control), 2 Gy, 4 Gy, 6 Gy, 8 Gy and 10 Gy. Each of the treatment levels is repeated as much as 4 and consists of 10 cloves of garlic. The observed quantitative data parameters are growing age, crop height, number of leaves, number of cloves, heavy bulbs, diameter of bulb, heavy cloves and diameter of cloves. The qualitative data parameters observed are bulb structures and bulb forms. Qualitative Data obtained is analyzed using various prints with advanced test of the smallest real difference (LSD). The results shows the irradiation of the influential gamma rays in the height of the plant, the number of leaves, the number of cloves, the weight of bulbs, the diameter of the bulb, the weight of cloves, and the diameter of garlic cultivars Gamma-ray irradiation produces a variety of bulb structures and bulb shapes. The parameters observed were structure and shape bulb based on IPGRI. Results showed that there were differences in the structure and shape of garlic bulbs.The structure of bulb are regular two-fan groups, regular multi-cloved radial, regular quadruple, regular two-cloved, and Irregular. The shape of bulb are Flat, Flat globe, Rhomboid, Broad oval, Globe and Ovate.

Effect of low dose-rate industrial Co-60 gamma irradiation on ZnO thin films: Structural and optical study

The effect of low-dose rate gamma rays irradiation on ZnO thin films of different thicknesses has been studied. Preferentially oriented (002) ZnO thin films have been deposited on Si (100) and glass substrates using radio frequency magnetron sputtering. ZnO films with c-axis-oriented Würtzite structure were obtained at room temperature. ZnO films with thickness of 200 nm and 600 nm were prepared and studied. The prepared films were irradiated using1.25-MeV gamma beam emitted from Cobalt sources (Co-60) with two different doses (2and 4 kGy) and the effect of the gamma irradiation on the optical and structural properties of the ZnO films was examined. The photoluminescence PL intensity was found to increase with the increasing of the irradiation dose in both thin and thick films. This finding allows improving the scintillation output signal of the material while keeping grain size unchanged if low dose rate irradiation is used, as X-ray diffraction patterns showed. Raman spectrum correlates with XRD results. The band gap extracted by UV transmittance spectrum was also identified.

Correspondence and difference between gamma-ray and neutron irradiation effects on organic materials in marine environment

Correspondence and difference between gamma-ray and neutron irradiation effects on organic materials in marine environment

Gamma-ray radiation effects in graphene-based transistors with h-BN nanometer film substrates

Radiation effects on graphene field effect transistors (GFETs) with hexagonal boron nitride (h-BN) thin film substrates are investigated using 60Co gamma-ray radiation. This study examines the radiation response using many samples with varying h-BN film thicknesses (1.6 and 20 nm thickness) and graphene channel lengths (5 and 10 μm). These samples were exposed to a total ionizing dose of approximately 1 Mrad(Si). I-V measurements were taken at fixed time intervals between irradiations and postirradiation. Dirac point voltage and current are extracted from the I-V measurements, as well as mobility, Dirac voltage hysteresis, and the total number of GFETs that remain properly operational. The results show a decrease in Dirac voltage during irradiation, with a rise of this voltage and permanent drop in Dirac current postirradiation. 1.6 nm h-BN substrate GFETs show an increase in mobility during irradiation, which drops back to preirradiation conditions in postirradiation measurements. Hysteretic changes to the Dirac voltage are the strongest during irradiation for the 20 nm thick h-BN substrate GFETs and after irradiation for the 1.6 nm thick h-BN GFETs. Failure rates were similar for most GFET types during irradiation; however, after irradiation, GFETs with 20 nm h-BN substrates experienced substantially more failures compared to 1.6 nm h-BN substrate GFETs.

Synergistic effect of gamma-ray irradiation and calcium oxide on corrosion inhibition of aluminum dihydric tripolyphosphate on mild steel

ABSTRACTAluminum dihydric tripolyphosphate (ADTP) was irradiated by using a 60Co gamma-ray source and a maximum dose up to 150 kGy, subsequently recombined with calcium oxide (CaO) by co-grinding, and the synergistic effects of gamma-ray irradiation and CaO on the anticorrosive performance of irradiated-ADTP on mild steel were studied. The efficiency of irradiated-ADTP and irradiated-ADTP/CaO as corrosion inhibitors for mild steel boards in 3.5% NaCl solution was determined by means of weight-loss determination, Tafel polarization and electrochemical impedance spectroscopy (EIS). The morphology of the irradiated-ADTP particles was observed by scanning electron microscopy (SEM). Results showed that irradiated-ADTP/CaO had good inhibiting properties for steel corrosion in the solution, with an efficiency of around 95% at gamma-ray absorbed dose of 150 kGy. But, the inhibiting efficiency of irradiated-ADTP in the absence of CaO decreased with the dose. The positive effect of the combination of gamma-ray irradiation and CaO was mainly attributed to the loosening lamellar structure of ADTP caused by gamma irradiation, which facilitated the neutralization reaction between ADTP and CaO.

Effect of Temperature and Gamma-Ray Irradiation on Optical Characteristics of Fiber Bragg Grating Inscribed Radiation-Resistant Optical Fiber

A new radiation-hard germano-silicate glass optical fiber with a pure silica glass buffer and a boron-doped silica glass inner cladding was fabricated for temperature sensor application based on the fiber Bragg grating (FBG) under γ-ray irradiation environment. The temperature dependences of optical attenuation at 1550.5 nm and Bragg reflection wavelength shift from 18 °C to 40 °C before the γ-ray irradiation were about 4.57×10−4 dB/ °C and 5.48 pm/ °C, respectively. The radiation-induced optical attenuation at 1550.5 nm and the radiation-induced Bragg reflection wavelength shift under the γ-ray irradiation with the total dose of 22.85kGy at 35 °C were about 0.03dB/m and 0.12nm, respectively, with the γ-ray irradiation sensitivity of 5.25×10−3 pm/Gy. The temperature and the γ-ray irradiation dependence of optical attenuation at 1550.5nm in the FBG written fiber with boron-doped silica glass inner cladding were about 6 times and 4 times lower than that in the FBG written fiber without boron-doped silica glass inner cladding under a temperature change from 18 °C to 40 °C and the γ-ray irradiation with the total dose of 22.85 kGy at 35 °C, respectively. Furthermore, the effect of temperature increase on the Bragg reflection wavelength of the FBG written fiber with boron-doped silica inner cladding was much larger about 1000 times than that of the γ-ray irradiation. However, no influence on the reflection power of the Bragg wavelengths and the full width at half maximum (FWHM) bandwidth under temperature and the γ-ray irradiation change was found. Also, after the γ-ray irradiation with the dose of 22.85kGy, no significant change in the refractive index was found but the residual stresses developed in the fiber were slightly relaxed or retained.

Radiation effects in printed flexible single-walled carbon nanotube thin-film transistors

In this study, the gamma ray radiation effect on the characteristics of inkjet-printed semiconducting single-walled carbon nanotubes (sSWCNTs) thin-film transistors (TFTs) is investigated. The devices with top gate dielectrics consisted of BaTiO3 and poly(methyl methacrylate) (PMMA) were characterized before and after 150 krad 60Co gamma radiation in air. It reveals that the radiation results in a positive threshold voltage shift from -0.5 to 3.6 V (with a drain voltage biased at -1 V). The hysteresis decreases slightly from 1.2 to 0.5 V, indicating that the BaTiO3/PMMA dielectric layer effectively encapsulates the sSWCNTs TFTs from absorbing molecules in the environment. Furthermore, the charge pumping current ICP is measured with a gate voltage pulsed at 100 kHz. The maximum ICP increases from 90 to 140nA, which translates to an increase in the interface trap density from 4.5×1011 to 1.1×1012 cm-2eV-1. The charge pumping measurements at the frequency of 10∼250 kHz show that the increase of ICP induced by radiation is obvious when f>30 kHz but is little when f<30 kHz, which indicates that the radiation induced charge traps locate near sSWCNTs. The BaTiO3/PMMA gate dielectric remains to be a good insulator with a leakage current of less than 60 pA after radiation. Such printed flexible TFTs with the polymer gate dielectric possess similar radiation tolerant compared to convention devices on rigid substrates.

Radiation-induced changes on poly(methyl methacrylate) (PMMA)/lead oxide (PbO) composite nanostructure

In the present study, results of the 60Co gamma-ray irradiation effect on the structural properties of the PMMA/PbO composite nanomaterial are presented. In order to explore the 60Co gamma-ray irradiation effect on PMMA/PbO thin film, the dielectric parameters have been calculated before and after two higher irradiation doses at room temperature in the frequency value of 1 MHz and 500 kHz. The important changes caused by the higher radiation in the dielectric properties in the depletion and accumulation regions have been attributed to the restructuring and reordering of the charges at the interface states.

A promising high-efficient radiation resistant laser crystal Nd:GSAG

In this study, the effect of gamma-ray irradiation on the spectral and laser properties of Nd:GSAG crystal is investigated. With 20 Mrad gamma-ray irradiation, the crystal’s absorption at around 808 nm and emission at 1060 nm are only affected slightly. In addition, the lifetime of the 4F3/2 → 4I11/2 transition becomes longer when increasing the irradiation doses. All these optical properties changes after the irradiation could be attributed to the formation of F+-centers in the crystal. Using LD pumping, high-efficient 1.06 μm continuous-wave laser operation was realized in the crystal. It is worthy to note that the laser efficiency is influenced slightly by the gamma-ray irradiation, which suggest that Nd:GSAG crystal can be considered as a potential efficient laser gain medium for being used in radiant environment.

Gamma-ray irradiation effects on the electrical properties of organic field-effect transistors

We investigated the changes in the organic transistor characteristics of poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) thin films upon high-energy gamma-ray irradiation. Devices based on both organic semiconductors showed a lower field-effect mobility and electrical current levels after gamma-ray irradiation. The threshold voltage of P3HT transistors shifted negative, while that of PCBM-based devices shifted positive. These changes in electrical performance of the devices can be utilized as a gamma-ray sensing elements.

Effect of Ag and γ-ray irradiation on the specific heat of glass transition of Se78Te20Sn2 glassy alloy

The specific heat of glassy materials is a significant parameter that reveals useful information about the local circumstances for the vitrification of a glass-forming melt through its solidification. However, the melt after the formation of glass is known as a highly viscous liquid. In the present work, we are reporting the effect of silver (Ag) on specific heat capacity of glass transition of Se78Te20Sn2 glass alloy in terms of glass and equilibrium specific heats (i.e., Cpg, and Cpe) and then in addition to it, we are reporting the effect of gamma-ray (γ-ray) irradiation (60Co source, 12 kGy dose) on the same glassy alloy. A comparative analysis of Ag addition and γ-ray irradiation on these thermodynamic parameters for the parent glass is discussed in detail.

Effects of gamma ray, electron beam, and X-ray on the reduction of Aspergillus flavus on red pepper powder (Capsicum annuum L.) and gochujang (red pepper paste).

Aspergillus flavus is the potential pathogenic mold in red pepper powder (Capsicum annuum L.) and gochujang (red pepper paste), which can produce mycotoxins. This study investigated the effects of gamma ray, e-beam, and X-ray irradiation on the reduction of A. flavus on red pepper powder and gochujang and physicochemical and sensory quality changes. Gamma ray and e-beam at 3.5 kGy reduced A. flavus effectively (>4 log), without deteriorating the physicochemical quality. Same dose of X-ray did not cause any deterioration of the physicochemical quality. However, reduction effect of A. flavus in red pepper powder and gochujang by 3.5 kGy X-ray was under 2 log. Further, sensory quality analysis showed no significant difference in color, appearance, texture, and overall acceptability after three irradiations. However, flavor changes of red pepper powder and gochujang after three irradiations were mentioned by panelists. In this study, gamma ray and e-beam irradiation were effective in eliminating A. flavus present in red pepper powder and gochujang, but X-ray irradiation was not effective. The results indicate gamma ray and e-beam are effective in controlling microorganisms present in powdery or paste foods, but the X-ray was not effective.

Effects of gamma irradiation on the electrical characteristics of trench-gate non-punch-through insulated gate bipolar transistor

We studied the effects of gamma-ray irradiation on the static and dynamic electrical characteristics of a trench-gate non-punch-through insulated gate bipolar transistor (IGBT) device. The threshold voltage and breakdown voltage decreased after irradiation, whereas the collector leakage current increased. Turn-on and turn-off switching times decreased and increased, respectively, with the irradiation dose. The irradiation-induced changes in the electrical characteristics can be attributed to the buildup of the positive oxide-trapped charges in the gate oxide by gamma irradiation. The evaluated characteristics data were compared with the data for gamma-irradiated planar-gate IGBTs reported in the literature. It was found that a significant degradation occurred in the shift of the threshold voltage and switching times for trench-gate IGBTs.

Application of Gamma Radiation on Hard Gelatin Capsules as Sterilization Technique and Its Consequences on the Chemical Structure of the Material.

Hard capsules are made from gelatin, an organic polymer obtained through the hydrolysis of collagen present in animal tissues. Gelatin can be degraded by microorganisms and some strategies can be used to control contaminating micro-organisms. Gamma irradiation is considered as an effective sterilization method; however, its application can alter the chemical structure of the irradiated product. Samples of hard gelatin capsules were irradiated at doses of 5, 15, and 25kGy at room temperature. The characterizations of the physical and chemical effects were evaluated by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry, and differential scanning calorimetry techniques. Furthermore, hard gelatin capsule samples were dissolved and inoculated with Bacillus subtilis, a Gram-positive spore-forming bacterium, to evaluate the effect of gamma ray radiation on bacterial counts. The results showed that gamma radiation did not interfere on physical parameters of the capsule, such as moisture content, mass, body and cap length, and disintegration time. Nevertheless, differential scanning calorimetry results demonstrated changes in the glass transition temperature, indicating the formation of crosslinking in irradiated capsules. It was observed that there were significant reductions on the inoculated bacterial population starting from the lowest irradiation dose and there was no detection of bacterial growth from the 15 kGy dose, while in the non-irradiated samples were found with 104CFUmL-1 of bacteria. Therefore, this work concludes that the gamma radiation is effective on the reduction of the microbial population, cause discrete physical-chemical alterations, and could be used as a hard capsule sterilization technique.

Comparative effect of high energy electron beam and 137Cs gamma ray on survival, growth and chlorophyll content in curcuma hybrid ‘Laddawan’ and determine proper dose for mutations breeding

Curcuma alismatifolia is an ornamental plant with a beautiful flower in the curcuma genus, which is popular in Thailand and other countries. C. alismatifolia has been improved as the market needs. This research aimed to induce mutations and to study the effects of electron beam and gamma ray on tissue culture of the Curcuma hybrid ‘Laddawan.’ Eight-weeks-old plantlets were irradiated by gamma ray with a Mark I irradiator at the dose rate of 3.74 Gy/min, at the Nuclear Technology Research Center, Kasetsart University. For the electron beam irradiation, samples were exposed to a high-energy electron beam. The lowest power of this machine is 10 MeV and the lowest radiation dose per cycle is 50 Gy (240 Gy/min). The comparison between the effects of gamma ray and electron beam irradiation at doses of 0, 50, 100 and 200 Gy showed that survival percentage, growth percentage, and chlorophyll content were significantly decreased (P<0.05) when radiation dose increased. The survival percentage, growth percentage and chlorophyll content of gamma-irradiated samples were higher than the electron beam-irradiated samples in the same dose. The results indicated the optimum dose range for gamma irradiation of Curcuma hybrid ‘Laddawan’ in tissue culture is 30 – 60 Gy and for electron beams the dose should be less than 50 Gy. New characteristics (variegated leaves and light green leaves) were found in M1V2.

Study of γ-ray radiation influence on SiO2/HfO2/Al2O3/HfO2/Al2O3 memory capacitor by C–V and DLTS

Gamma-ray radiation effects on the SiO2/HfO2/Al2O3/HfO2/Al2O3 based charge trapping memory have been investigated. Capacitance–voltage (C–V) and deep level transient spectroscopy (DLTS) measurements were applied to study the change in electrical properties from total dose radiation. C–V results showed a negative shift of flat-band voltage while dc memory window degraded after gamma-ray radiation. For DLTS result, two original peaks were found degraded while two new peaks appeared after radiation. Both C–V and DLTS results show that Gamma ray leads to the degradation of trapping effect.