Atom Indonesia (E-Journal)
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Characteristics of Stable Isotope Compositions (δ18O and δ2H) of Surface Water in Bengkulu City
Get PDFIndonesia as an archipelagic country has a unique location and topography, and the El Niño-Southern Oscillation (ENSO) is observed in this region, resulting in complex weather and climate variability. As a result, Indonesia including Bengkulu experiences regular natural disasters. Stable isotopes (δ18O and δ2H) have been used as natural tracers in solving water resources and water-related problems. The aim of this research is to investigate the variations of stable isotopes in Bengkulu City from three locations, namely Serut and Hitam Rivers and the Universitas Bengkulu (UNIB) lake, and to understand the hydrological processes in Bengkulu City. In this research, samples of surface water from Serut and Hitam Rivers and UNIB Lake in Bengkulu City were collected over five months between December 2018 and April 2019. Stable isotope compositions of these water samples were examined to understand the local hydrological processes. The result shows that the water samples are generally situated at the right side of Local Meteoric Water Line (LMWL) in δ18O and δ2H plot, indicating that water samples are more enriched in 18O and 2H as compared with the rainwater due to fractionation processes. The surface water samples define a local evaporation line with a slope of 6.536 while the LMWL has a slope of 7.848. This result indicates a significant evaporation effect on water bodies. Moreover, the slope of the regression line in all water samples was lower than the LMWL, in order of Serut River (7.696) Hitam River (6.851) UNIB Lake (6.436), indicating that UNIB Lake experienced more significant evaporation than river waters, resulting in enrichment in heavy isotopes. Serut River, one of largest river in Bengkulu City, which also plays an important role in flooding in Bengkulu City, has a regression equation similar to the regression line of rainwater (LMWL). It may be indicated that surface water from Serut River is strongly influenced by rainwater. Consequently, high amount of rainfall can affect the water level of Serut River, and can be associated with flooding. Therefore, long-term monitoring of stable isotopes is very important in the future to provide the pattern of changes in isotopic variation, particularly during flood and drought events as climate-disaster mitigation effort
Comparison of Gamma Index Passing Rate in Several Treatment Planning System Algorithms
Get PDFThe verification of dose calculation algorithm in a new Treatment Planning System (TPS) can be evaluated by comparing the passing rate of the gamma index analysis of the evaluated algorithm and the clinically implemented algorithms. In the present investigation, the gamma index passing rates was investigated as the reference data in the verification of the new three-dimensional TPS. The algorithms which are used in this study are Pencil Beam Convolution (PBC) version 11.0.31 and Anisotropic Analytical Algorithm (AAA) version 11.0.31 in Eclipse v.11 TPS, and Fast Convolution (FC), Adaptive Convolution (AC), and Collapsed-Cone Convolution (CCC) in Pinnacle3 v.7.6c TPS. The 6 MV X-ray beam configurations were varied in the depth of measurement points, field sizes, source-to-surface distances, and wedge angles. The dose measurement was done using MatriXX Evolution and PTW 2D-array seven29. Then, OmniPro ImRT and Verisoft 3.1 software were chosen to analyze the gamma index from varied gamma criteria (3 %/3mm, 2 %/3mm, 3 %/2mm, and 2 %/2mm). Overall, the passing rate of AAA is the highest rate obtained of all algorithms. For gamma criterion of 2 %/2mm, the passing rate of AAA was 93.18 % ± 7.21 %, the passing rate of PBC was 89.76 % ± 7.21 %, and the passing rate of convolution algorithms was 76.84 % ± 11.10 %
Comparison of 192Os(p,n)192Ir and 192Os(d,2n)192Ir Nuclear Reactions for 192Ir Production
Get PDFIridium-192 (192Ir ) is a radionuclide currently suggested for brachyteraphy. One of the methods employed to produce high purity 192Ir is by irradiation of Osmium-192 (192Os) target using cyclotron. The success of 192Ir radionuclide production in cyclotrons requires deep understanding of irradiation parameters, including particle energy, target preparation and thickness, particle beam curent and irradiation time. Therefore, theoretical calculations of the 192Ir radioactivity yields should be carried out as a preliminary measure for more efficient 192Ir production. In this study, 192Ir production was simulated using the SRIM 2013 program to determine the optimum target thickness while the nuclearcross-section data were extracted from TENDL 2017. Two nuclear reactions for 192Ir production yield calculations were compared, i.e., 192Os(p,n)192Ir and 192Os(d,2n)192Ir. The radioactivity yields for 192Os(p,n)192Ir nuclear reaction was found to be lower than 192Os(d,2n)192Ir reaction. For proton and deuteron energy of 30 MeV, the maximum radioactivity yield was 6.79 GBq for 192Os(p,n)192Ir and 26.14 GBq for 192Os(d,2n)192Ir. Several radionuclide impurities such as 191mIr, 190Ir, 191Os and 189Re were predicted to be generated during 192Os(p,n)192Ir reaction for proton incident energy between 1 and 30 MeV; meanwhile, 192Ir, 191mIr, 193Os, 193mIr, 192mOs and 191Os radionuclides were expected to contaminate during 192Os(d,2n)192Ir reaction for deuteron energy between 1 and 30 MeV. Results of this study can be used as a reference for future 192Ir radionuclide production when proton or deuteron beams are considered to be employed
Calculation of Energy Levels and Reduced Electric Quadrupole Transition Probability for 22F Isotope Using Oxbash Code
Get PDFA study on the calculation of energy levels and reduced electric quadrupole transition probability for fluorine-22 isotope using Oxbash Code has been carried out. The shell model and OXBASH was used to calculate the energy levels and probability of quadratic transition B(E2) of the 22F isotope in the SD region through PW, CWH active interactions. A comparison was made between the calculation results and the experimental data. The comparison shows considerable consistency with the experimental results. The total angular momentum of the ground level 4+1 was confirmed when comparing with the experimental values. A significant consistency was obtained for the calculated energy values MeV (1.734, 2.387, 2.946) with the available experimental values of the same angular momentum (1+1,12+,4+2). It can be concluded that the reduced transition probabilities B(E2) can be calculated using the PW, CWH reactions and OXBASH code
Neutronics Assessment of Accident-Tolerant Fuel in Advanced Power Reactor 1400 (APR1400)
Get PDFSafety and reliability are the most desirable conditions that each nuclear power plant should improve. Since the Fukushima Daiichi accident, Accident-Tolerant Fuel (ATF) has been extensively researched to improve the performance of the nuclear fuel system. This paper presents the investigation of the ATF system from a neutronics perspective, which positively reflects on the performance of the APR-1400 nuclear power plant. Several advanced fuel candidates such as UC, U3Si2, and UN, which have better thermophysical properties than current UO2 nuclear fuel, have been considered. Meanwhile, advanced cladding candidates such as FeCrAl, Zr-alloy with coating, and SiC which can reduce or even eliminate the oxidation rate of current Zr-alloy cladding have been adopted in this study. The Monte Carlo Serpent code, in conjunction with ENDF/B-VII.1 nuclear data library, has been used to calculate and evaluate the important neutronics parameters at the assembly level such as the fuel residence time, discharge burnup, kinetics parameters, pin power distribution, temperature reactivity feedbacks, and fissile evolution. The advanced fuels show better neutronics performance than the current UO2 fuel. In addition, SiC provides optimum neutronic performance as cladding
Radiolabeling Technique of Silver Nanoparticles (AgNPs) with Iodine-131 Radionuclide
Get PDF Radiotherapy is an effective cancer therapy, where a certain dose of radiation is aimed specifically at target and is unaffecting to normal tissue. A selectiveradionuclide must be attached to the specific targeted organ. In this research, silver nanoparticles (AgNPs) were labeled with radionuclide of iodine-131 (131I) to be used in radiotherapy. Silver nanoparticles were synthesized using silver nitrate 0.0005 M, sodium borohydride 0.002 M, polyvinylpyrrolidone 0.3 % (w/v) and natrium chloride 1.5 M, and then followed by purification by centrifugation. Characterization was carried out with UV-Vis spectrophotometer, transmission electron microscope, particle size analyzer, and zeta-sizer. The results show that the maximum absorbance is on a wavelength of 398 nm, spherical shape with a diameter of 10 nm, polydispersity index of 0.455, and zeta potential value of –8 mV. The radiolabeling was done by adding sodium iodide-131 which had been oxidized by chloramine-T and immobilized in AgNPs colloidal solution, and the activity was then measured using a dose calibrator. The identification of radionuclide showed that the sample was free of impurities. The optimum system of radiochemical purity was obtained using Whatman 1 paper strip as the stationary phase and a mixture of methanol: water: ammonium acetate (1:1:1) as the mobile phase, which gave 96 % purity. This method is suitable for radiolabeling AgNPs with 131I to be used for radiotherapy
Construction and Evaluation of a Multipurpose Performance Check Phantom for Computed Tomography
Get PDFThe use of computed tomography (CT) has become a common practice in medical diagnosis in Indonesia. Its number, however, is not matched by the availability of dedicated-performance-check phantoms. This paper aims to describe the design, construction, and evaluation of an in-house phantom for CT performance check that accommodates both radiation dose measurement and image quality performance checks. The phantom is designed as laser-cut polymethyl methacrylate (PMMA) slabs glued together to form a standard cylindrical shape, with spaces to place dose measurement and image quality modules. In this paper, measurement results on both aspects are discussed and compared with standard phantoms and other works. For dose measurement, the constructed phantom exhibited the greatest absolute discrepancy against the reference standard phantom of 8.89 %. Measurement of the CT number linearity and modulation transfer function (MTF) yielded, at most, 7.51 % and 5.07 % discrepancies against Catphan 604, respectively. Meanwhile, although found to be more linear in the phantom-based contrast linearity test, the use of the in-house phantom for clinical image contrast threshold determination requires further study. For noise power spectrum (NPS) measurement, accurate results were obtained within a limited range of spatial frequency
Application of Digital Anti-Coincidence Counting Method for Primary Activity Determination of 59Fe
Get PDFAs a radiopharmaceutical, the use of 59Fe is classified as a high pharmaceutical risk product. Therefore, a standard reference for activity measurement of 59Fe is necessary to ensure its metrological aspect. This paper describes an alternative method for primary activity determination of 59Fe for establishing a standard reference. The 59Fe solution was prepared using two different cocktails and measured by the 4pb(LS)-g counting system using a digital anti-coincidence counting method with emulated live-time of the extending dead-time. A final activity results at the reference time for the two samples series are (473.32± 2.55) kBq/g and (477.14 ± 2.42) kBq/g with quoted uncertainty evaluated at k = 1. The final activity was compared to the value obtained from the other two coincidence counting method and found to be in a good agreement within its uncertainty value
