Gamma Radiation Source Research Articles

Determination of void fraction in two phase liquid-gas flow using gamma absorption

Full description of a two-phase liquid-gas flow requires the designation of lot parameters. First one, which describes which part of the pipeline is fulfilled by the gas, is the void fraction. Moreover the share of gas in a flowing mixture determines the structure of the flow and also affects the velocity of the individual phases. In that case void fraction can be determined by use the gamma absorption method, as well as other flow parameters may be evaluated by the same equipment. In addition the article presents the calibration of radiometric set, which consists of gamma radiation source Am-241 and scintillation probe NaI(Tl), for determination of the void fraction, illustrated by exemplary results of the described method application to various structures of air-water flow in the horizontal pipeline.

Dosimetry characteristics of HDPE–SWCNT nanocomposite for real time application

In this experimental work, different dosimetric characteristics of high density polyethylene-single wall carbon nanotube nanocomposite were investigated. The nanocomposite samples were prepared with different nanotube contents of 0.22, 0.25, and 0.39 weight percentages which were before, exactly in, and after percolation region of the nanocomposite, respectively. The samples were exposed to 60Co gamma radiation source over the dose rate of 65–214mGy/min, while the applied bias was 100V. A linear response achieved for the sample contained 0.25 nanotube wt% verified that the percolation threshold is the optimum point for dosimetric purposes. The current–voltage characteristics curve measured for 0.25 CNT wt% nanocomposite showed that the behavior of this sample was bias polarity independent. Also, the results showed that the response of this nanocomposite was energy-independent. The maximum discrepancy of photocurrent due to angular variation within 0–90° with respect to beam incidence and the reproducibility of the response were measured as 5.4% and 0.8%, respectively. The stability study showed that this material may be suitable for protection dose level control. Therefore, this kind of nanocomposite requiring calibration can be used as a real-time dosimeter.

Sparse Approximation-Based Maximum Likelihood Approach for Estimation of Radiological Source Terms

A computationally efficient and accurate method is presented for identifying the number, intensity and location of stationary multiple radiological sources. The proposed method uniformly grids the region of interest resulting in a finite set of solutions for the source locations. The resulting problem is a sparse convex optimization problem based on ${{\cal L}_1}$ -norm minimization. The solution of this convex optimization encapsulates all information needed for the estimation of source terms; the values of the nonzero elements of the solution vector approximates the source intensity, the grid points corresponding to the nonzero elements approximates the source locations, and the number of nonzero elements is the number of sources. The accuracy limited by the resolution of the grid is further improved by making use of the maximum likelihood estimation approach. The performance of sparse approximation based maximum likelihood estimation is verified using real experimental data acquired from radiological field trials in the presence of up to three point sources of gamma radiation. The numerical results show that the proposed approach efficiently and accurately identifies the source terms simultaneously, and it outperforms existing methods which have been used for stationary multiple radiological source terms estimation.

The optimization of radiation protection composition

The purpose of the study is to develop an algorithm for designing the composition of homogeneous radiation protective materials (RPM) for the radiation protection optimization. Homogeneous radiation protective materials of the Abris type were used in the studies, the manufacturing technology for which makes it possible to obtain the required concentrations of filling agents. The attenuating capacity of a radiation protective material with the barite, lead and tungsten concentrations of 20–80% was estimated using high-precision codes. Experimental studies into the protective properties of the Abris material with different concentrations of filling agents were conducted to verify the calculation results. For the experiment, five sources of gamma radiation (60Co, 58Co, 198Au, 54Mn, 24Na) with typical radiation energies were generated in the IVV-2M research reactor. A dedicated facility and a DKS-AT1123 measuring device were also used.As the result of an integrated research, calculated dependences of the attenuation factors have been obtained for the radiation produced by typical radiation sources, and for different RPM compositions and thicknesses. This data forms the input for the optimization of radiation protection. The design of the homogeneous RPM composition is highly promising in terms of the approach to radiation protection optimization. As follows from a comparison of the investigation results for the γ-radiation dose attenuation factors for homogeneous protective materials of the Abris type, depending on composition and thickness, the experimental data differs from the values obtained by calculation by not more than 5%. The Abris-type homogeneous RPM manufacturing technology makes it possible to provide the required protective properties for particular exposure conditions (composition of radioactive contaminants).

Development and Cultivation of Local Kidney Bean (<i>Phaseolus Vulgaris </i>L) Through Breeding to use Multi gamma Irradiation Technique (Nuclear)

Mutation on the all species of plant were generally caused by gamma or multi gamma radiation sources. The largest effect of that was occurred on chromosome and genetic factor, specially on structure and composition of chromosome and Deoxyribo Nucleic Acid (DNA). This case can be used for breeding of several important plants in Agricultural science. The objectives of this research is to develop of local kidney bean (Phaseolus Vulgaris L) that tolerant to dry condition and high production. Multi gamma radiation and selection are the main methods to use in this research and other methods comprised of observation/survey, sampling, comparison, analyzing and interpretation. The number of mutant varieties of kidney bean (superior seed of mutant) obtained in this research based on selection method are ten mutant varieties. The growth percentage rate, protein content of control and mutant variety of kidney bean were estimated respectively of 97, 22.54 and 24.21%. The production of mutant kidney bean was between 3.97 tons/ha up to 5.28 tons/ha and the average production was 4.71 tons/ha. The average production of control was 2.60 tons/ha, in order that the production was significantly increased by 44.80%.

Total ionizing dose effects of domestic SiGe HBTs under different dose rates

The total ionizing radiation (TID) response of commercial NPN silicon germanium hetero-junction bipolar transistors (SiGe HBTs) produced domestically are investigated under dose rates of 800 mGy(Si)/s and 1.3 mGy(Si)/s with a Co-60 gamma irradiation source. The changes of transistor parameters such as Gummel characteristics, and excess base current before and after irradiation, are examined. The results of the experiments show that for the KT1151, the radiation damage is slightly different under the different dose rates after prolonged annealing, and shows a time dependent effect (TDE). For the KT9041, however, the degradations of low dose rate irradiation is higher than for the high dose rate, demonstrating that there is a potential enhanced low dose rate sensitivity (ELDRS) effect for the KT9041. The possible underlying physical mechanisms of the different dose rates responses induced by the gamma rays are discussed.

The Dosimetric Parameters Investigation of the Pulsed X-ray and Gamma Radiation Sources

The most common type of radiation used for diagnostic purposes are X-rays. However, X-rays methods have limitations related to the radiation dose for the biological objects. It is known that the use of the pulsed emitting source synchronized with the detection equipment for internal density visualization of objects significant reduces the radiation dose to the object. In the article the analysis of the suitability of the different dosimetric equipment for the radiation dose estimation of the pulsed emitting sources is carried out. The approbation results on the pulsed X-ray generator RAP-160-5 of the dosimetry systems workability with the pulse radiation and its operation range are presented. The results of the dose field investigation of the portable betatron OB-4 are demonstrated. The depth dose distribution in the air, lead and water of the pulsed bremsstrahlung generated by betatron are shown.

LiCaAlF6 scintillators in neutron and gamma radiation fields

Intentionally doped LiCaAlF6 (LiCAF) single crystals are prospective scintillators, especially for thermal neutron detection through the 6Li(n,t)4He nuclear reaction. Four different LiCAF scintillator samples were tested in various neutron and gamma fields. Two of the tested samples were LiCAF:Eu and LiCAF:Eu,Na single crystals, and another two samples were made of LiCAF:Eu micro crystals dispersed in transparent rubber, with different rubber dimensions. All LiCAF samples contain lithium enriched to[Formula: see text]Li. A plutonium–beryllium source was used as a neutron source. The neutron spectrum was modified by moderator and filter to get different ratios between thermal, epithermal and fast neutron fluence rates. The MCNP code was used for calculations of the fluence rates for different configurations. Radionuclides [Formula: see text]Cs and [Formula: see text]Co were applied as gamma radiation sources. The light signal from the scintillator was evaluated with a photomultiplier and a multichannel analyzer. The purpose of this work was to study the characteristics of LiCAF scintillators, especially the ability to discriminate signals from neutron and gamma radiation, which is the basic scintillator condition for neutron detection in mixed neutron-gamma radiation fields. Generally, the discrimination can be done by the pulse height and/or the pulse shape of the evaluated signals. Both methods can be used for a LiCAF scintillator. However, only the pulse height discrimination method is discussed in this paper. The possibility of fast neutron detection with LiCAF scintillators was also tested.

Measurement Technique of Dose Rate Distribution of Ionization Sources with Unstable in Time Beam Parameters

The article describes a new technique for the average values of radiation dose measurement for the unstable gamma-ray sources which are used in non-destructive testing. The method is based on usage of different types of compact accumulative dosimeters. Spatially distributed position sensitive dosimetry system based on compact sensitive elements was created. Size and spatial resolution of the system of the dosimetry system are chosen taking into account sources characteristics. The proposed method has been tested on the measurement of dose distribution of several sources of X-ray and gamma-radiation based on X-ray tubes, electronic accelerator betatrons and linear electron accelerators.

IMITATION OF STANDARD VOLUMETRIC ACTIVITY METAL SAMPLES

Due to the specific character of problems in the field of ionizing radiation spectroscopy, the R&D and making process of standard volumetric activity metal samples (standard samples) for calibration and verification of spectrometric equipment is not only expensive, but also requires the use of highly qualified experts and a unique specific equipment. Theoretical and experimental studies performed have shown the possibility to use imitators as a set of alternating point sources of gamma radiation and metal plates and their use along with standard volumetric activity metal samples for calibration of scintillation-based detectors used in radiation control in metallurgy. Response functions or instrumental spectra of such spectrometer to radionuclides like 137 Cs, 134 Cs, 152 Eu, 154 Eu, 60 Co, 54 Mn, 232 Th, 226 Ra, 65 Zn, 125 Sb+ 125m Te, 106 Ru+ 106 Rh, 94 Nb, 110m Ag, 233 U, 234 U, 235 U and 238 U are required for calibration in a given measurement geometry. Standard samples in the form of a probe made of melt metal of a certain diameter and height are used in such measurements. However, the production of reference materials is costly and even problematic for such radionuclides as 94 Nb, 125 Sb+ 125m Te, 234 U, 235 U etc. A recognized solution to solve this problem is to use the Monte-Carlo simulation method. Instrumental experimental and theoretical spectra obtained by using standard samples and their imitators show a high compliance between experimental spectra of real samples and the theoretical ones of their Monte-Carlo models, between spectra of real samples and the ones of their imitators and finally, between experimental spectra of real sample imitators and the theoretical ones of their Monte-Carlo models. They also have shown the adequacy and consistency of the approach in using a combination of metal scattering layers and reference point gamma-ray sources instead of standard volumetric activity metal samples. As for using several reference point gamma-ray sources with radionuclide like 152 Eu, 232 Th, 226 Ra etc, they allow, in a combination of metal scattering layers, to compensate for the absorption of low energy gamma rays in the metal and to generate the desired response in the backscatter peak range, and finally to get the correct amplitude distribution that is equivalent to interaction effects that occur in the volumetric standard sample with radionuclide uniformly distributed in it.

Decolorization and decontamination of textile wastewater by gamma irradiation in presence of H2O2

Gamma irradiation is a contemporary concept for the treatment of textile wastewater. The organic pollutants and coloring materials of wastewater can be decomposed acceptably by gamma irradiation. However, the process efficiency can be improved significantly by integrating H2O2 as an additive with wastewater during irradiation. The treatment of combined textile wastewater collected from a knit dyeing industry was carried out using a Cobalt-60 gamma radiation source at 10 kGy irradiation dose with a dose rate of 13 kGy/h in presence of 0.5, 1.0, 2.0, and 3.0% concentrations of H2O2. Then the change in pH and decoloration percentage, reduction in total suspended solids (TSS), five-day biological oxygen demand (BOD5), and variation of chemical oxygen demand (COD) were extensively investigated. It was observed that colored wastewater become almost colorless due to destruction of the chromophore group of the dye molecules by irradiation. Moreover, the alkaline pH of wastewater is also reduced to neutral condition by fragmentation of larger dye macromolecules resulting in the formation of smaller acidic organic compounds. The degradation of the solid particles and refractory organic matters leads to a considerable reduction in TSS and BOD5 values and consequently the COD of wastewater after irradiation. However, the COD values were found to increase in presence of H2O2 by dichromate method as it behaves as a reductant and oxidized by potassium dichromate resulting in a significant increment in COD reading. So it can be summarized that the application of gamma irradiation with the incorporation of H2O2 is a promising tool for the treatment of textile wastewater by decontaminating its organic pollutants effectively. This effectual degradation of organic matter can eliminate environmental hazard significantly after discharging a large volume of irradiated wastewater to the environment with the minimum concentration of perilous organic matters and coloring substances.

Scope of reusing and recycling the textile wastewater after treatment with gamma radiation

Fresh water is a precious natural resource that has been currently facing a severe stress because of its growing consumption by the industrialised civilisation. The global scarcity of fresh water has warranted an increasing demand for the treatment, recycling and reusing of wastewater for industrial purposes. This paper investigates the use of high energy gamma radiation to degrade and decontaminate combined textile wastewater and its potential application in textile wet processing and reuse for irrigation purposes. The treatment was carried out using a Cobalt-60 gamma radiation source at 10 kGy irradiation dose with a dose rate of 13 kGy/h. The change in pH, decolouration percentage, reduction of total suspended solids, total dissolved solids, biological oxygen demand and chemical oxygen demand, variation of electrical conductivity and heavy metal content of irradiated wastewater were extensively investigated. Then the treated wastewater was recycled for cotton fabric processing and reused in the irrigation of Malabar spinach plant. The detailed experimental results demonstrated that the irradiated wastewater can be satisfactorily used as an alternative to fresh water for scouring-bleaching and dyeing of cotton fabric. The risk to human health of fabric dyed with irradiated wastewater was also investigated. Carcinogenetic risk analysed by Gas chromatography–mass spectrometry showed the presence of banned amine in dyed fabric under the detection limit of 10 ppm and the absence of formaldehyde, signifying the non-toxicity of the fabric for human health. In case of a potential use in irrigation, treated wastewater was applied to Malabar spinach plant and compared with a controlled planting using the underground fresh water for irrigation. The plant irrigated with irradiated wastewater exhibited a better growth in terms of leaf count, root length and plant growth. It was further revealed that degradation of the textile dyes by gamma radiation led to an increase in nitrogen content in the irradiated wastewater that itself acted as a biofertiliser providing additional nutrient for a better growth of the aforementioned plant. So it can be concluded that gamma irradiation is a promising tool for the degradation and decontamination of textile wastewater for its safe recycling in textile wet processing and reuse as irrigation water having fertilising properties. Furthermore, the effectual reusing and recycling of irradiated wastewater demonstrated in this research work bear its scientific credibility in application field where consumption of million litres of fresh water per day and concurrently discharging same amount of effluent could be reduced considerably in a single textile dyeing industry.

Channeled positrons as a source of gamma radiation

The possibility of channeling the low-energy (5-20 MeV) relativistic positrons around separate crystallographic axes with coaxial symmetry of negative ions in some types of crystals is shown. The process of annihilation of positrons with electrons of medium was studied in detail. The lifetime of a positron in the channeling regime was obtained to be 10-6 s that exceeded those for conventional cases in 109-108 times.

Cellulose based cationic adsorbent fabricated via radiation grafting process for treatment of dyes waste water

A cationized adsorbent was prepared from cellulosic cotton fabric waste via a single step-green-radiation grafting process using gamma radiation source, wherein poly[2-(methacryloyloxy) ethyl]trimethylammonium chloride (PMAETC) was covalently attached to cotton cellulose substrate. Radiation grafted (PMAETC-g-cellulose) adsorbent was investigated for removal of acid dyes from aqueous solutions using two model dyes: Acid Blue 25 (AB25) and Acid Blue 74 (AB74). The equilibrium adsorption data was analyzed by Langmuir and Freundlich isotherms, whereas kinetic data was analyzed by pseudo first order, pseudo second order, intra particle diffusion and Boyd's models. The PMAETC-g-cellulose adsorbent with 25% grafting yield exhibited equilibrium adsorption capacities of ∼540.0mg/g and ∼340.0mg/g for AB25 and AB74, respectively. Linear and nonlinear fitting of adsorption data suggested that the equilibrium adsorption process followed Langmuir adsorption isotherm model, whereas, the kinetic adsorption process followed pseudo-second order model. The multi-linearities observed in the intra-particle kinetic plots suggested that the intraparticle diffusion was not the only rate-controlling process in the adsorption of acid dyes on the adsorbent, which was further supported by Boyd's model. The adsorbent could be regenerated by eluting the adsorbed dye from the adsorbent and could be repeatedly used.

A directional gamma-ray detector based on scintillator plates

A simple device for determining the azimuthal location of a source of gamma radiation, using ideas from astrophysical gamma-ray burst detection, is described. A compact and robust detector built from eight identical modules, each comprising a plate of CsI(Tl) scintillator coupled to a photomultiplier tube, can locate a point source of gamma rays with degree-scale precision by comparing the count rates in the different modules. Sensitivity to uniform environmental background is minimal.

A new accurate and flexible index to assess the contribution of building materials to indoor gamma exposure

The role of building materials as a source of gamma radiation has been recognized in the new EU Basic Safety Standards Directive which introduces an index I to screen building materials of radiological concern. This index was developed to account for average concrete values of thickness and density, the main structural characteristics of building materials that have an effect on gamma irradiation. Consequently, this screening procedure could be unfit in case of significantly different density and/or thickness of the building materials under examination. The paper proposes a more accurate and flexible activity concentration index, accounting for the actual density and thickness of building materials.

Spectral anomaly methods for aerial detection using KUT nuisance rejection

This work discusses the application and optimization of a spectral anomaly method for the real-time detection of gamma radiation sources from an aerial helicopter platform. Aerial detection presents several key challenges over ground-based detection. For one, larger and more rapid background fluctuations are typical due to higher speeds, larger field of view, and geographically induced background changes. As well, the possible large altitude or stand-off distance variations cause significant steps in background count rate as well as spectral changes due to increased gamma-ray scatter with detection at higher altitudes. The work here details the adaptation and optimization of the PNNL-developed algorithm Nuisance-Rejecting Spectral Comparison Ratios for Anomaly Detection (NSCRAD), a spectral anomaly method previously developed for ground-based applications, for an aerial platform. The algorithm has been optimized for two multi-detector systems; a NaI(Tl)-detector-based system and a CsI detector array. The optimization here details the adaptation of the spectral windows for a particular set of target sources to aerial detection and the tailoring for the specific detectors. As well, the methodology and results for background rejection methods optimized for the aerial gamma-ray detection using Potassium, Uranium and Thorium (KUT) nuisance rejection are shown. Results indicate that use of a realistic KUT nuisance rejection may eliminate metric rises due to background magnitude and spectral steps encountered in aerial detection due to altitude changes and geographically induced steps such as at land–water interfaces.

Low Dose Gamma Ray Exposure in Mandala

This paper carries out a study on low dose gamma ray exposure in mandala. The objective of this research is to explain in scientific terms a phenomenon in a very unnatural circumstance which will relate the radiation of color energy and frequency of mandala effects resembling the descriptive properties of matter interaction of gamma radiation. There are three natural sources of gamma radiation, the gamma decays in radio isotopes, cosmic ray in high-frequency level and rare terrestrial gamma-ray flashes. These aforementioned sources of gamma radiation have high-energy photons and huge production of electrons which are generally dangerous and biologically hazardous. Emission of X-ray photons has photoelectric effect that penetrates to the bones and unsafe irradiation procedures may cause burns and cancer. Another classic observation of photoelectric effect occured in metals emitting electrons when light shines upon them such as in solar panel technology. While in low-intensity, it is possible that light can eject electrons through discrete packet of photon energy, linking energy and frequency to quantify energy. Without reaching and exceeding the threshold of frequency, there are no electrons reducing or increasing the energy transfers in any chemical interaction regardless of the amplitude and exposure to light. In physics, this light can be the gamma rays, X-rays, microwaves and radiowaves that emits and absorbs tiny packets identified as “photons”. The relevance of this research paper encourages mandala energy as the medium for further studies and test theories on low-gamma radiation healing with anti-ageing benefits, the prototype and its effects is self-explanatory related to perpetual motion mechanics theorized in graviton and its technology may support manufacturing industries related to medicine, food production, energy and supply of clean water.

Influence of alpha and gamma radiolysis on Pu retention in the solvent TBP/kerosene

Abstract In light of the issue of radiolysis of the solvent system in PUREX process, alpha and gamma radiation stability of tributyl phosphate (TBP)/kerosene (OK) have been studied in this paper, in which 238Pu dissolved in the organic phase and 60Co are selected as alpha and gamma irradiation sources, respectively. The amount of the degradation products not easily removed after the washing process has been measured by the plutonium retention. The effects of the absorbed dose, the TBP volume fraction, the cumulative absorbed dose and the presence of UO2 2+ and Zr4+ on the radiolysis of the solvents have been investigated. The results have indicated that the Pu retention increases with the increase of the absorbed dose after alpha or gamma irradiation, and is larger for the solvent containing less TBP. There is competition between UO2 2+ and Pu4+ to complex with the degradation products, and Zr4+ accelerates the radiolysis of the system.

Development of a semi-autonomous directional and spectroscopic radiation detection mobile platform

This paper presents a method for a small, inexpensive mobile robot equipped with a single high resolution scintillation detector to quickly survey an area and convey information about local sources of gamma radiation to a remote human operator. This is achieved by surrounding the detector with a lead sheath that blocks all gamma-rays except those incident along the detector's axial direction. A 180° horizontal scan is performed by rotating the detector and a directional profile of gamma radiation is constructed. In addition, a 180° visual panorama of the local area is assembled using a camera mounted on the detector. A plot of the detector count rate versus angle is then overlaid on top of the visual panorama and visible peaks clearly indicate the direction of local gamma radiation sources. Measuring the energy spectrum of gamma-rays in each direction produces a 2D count frequency histogram where distinct peaks indicate the energy and direction of local gamma-ray sources allowing the identification of different radio-isotopes. The mobile robot can use the peaks as goal directions and autonomously move towards gamma-ray sources.