Journal of Nuclear Sciences

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https://dspace.ankara.edu.tr/handle/20.500.12575/39762

The Journal of Nuclear Sciences (JNS) is published on behalf of Ankara University Institute of Nuclear Sciences, on behalf of Ankara University. The printing costs for the print version of the journal are supported by Ankara University, while the online version is provided free of charge by DergiPark ULAKBİM services. The Dergipark system does not require any subscription from readers. Everyone can access the articles free of charge. The Journal of Nuclear Sciences (JNS) is an open access and cost-free peer-reviewed international scientific journal acting in the field of nuclear sciences. No author fee is charged from beginning to end during the submission, evaluation, and publication of the article to the journal.

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Ground-state properties of some N=Z nuclei
(Ankara : Ankara Üniversitesi, 2017) Akkoyun, S.; Bayram, T.; Şentürk, Ş.; Fen Fakültesi
The ground-state properties of 64Ge, 68Se, 72Kr and 76Sr (N=Z) nuclei have been investigated by using Hartree-FockBogolibov (HFB) method with Sly4 Skyrme forces, Relativistic Mean Field (RMF) model with NL3 and recently proposed DEFNE interaction parameters sets. For determination of ground-state, axially deformed shape and quadrupole moment constrained calculations have been employed in RMF model. The results of the present study have been compared with each other and available experimental data in the literature. The ground-state binding energies, neutron, proton and charge radii, quadrupole moment deformation parameters of these nuclei have been calculated. Furthermore, neutron skin thickness of the above mentioned nuclei as a function of deformation parameter have been obtained and discussed in detail.
On the Role of Strong Coupling Constant and Nucleons in Understanding Nuclear Stability and Binding Energy
(Ankara : Ankara Üniversitesi, 2017) Seshavatharam, U.V.S.; Lakshminarayana, S.; Fen Fakültesi
By considering nucleon and electron rest masses and with reference to nuclear charge radius and strong coupling constant, we make an attempt to understand beta stability line and nuclear binding energy in a simplified semi empirical approach. In this context, we consider ( 1 α s ) ( e 2 8 π ϵ 0 R 0 ) ≅ 4 . 8 6 ( α s 1 )( 8πϵ 0 R 0 e 2 )≅4.86 MeV as a single nuclear binding energy coefficient or potential.
Simulation of an anomalous behavior of thermoluminescence glow peak of quartz from Nigeria
(Ankara : Ankara Üniversitesi, 2017) Oniya, E. O.; Olubi, O. E.; Fen Fakültesi
Mechanism of the experimentally observed anomalous shift of a thermoluminescence (TL) glow peak that varied with irradiation dose is yet to be fully established. A theory that the anomalous peak must have contained more than one first order composite peaks each with different TL dose characteristics has been one major explanation proposed to explain this observation. This work was undertaken to simulate the anomalous glow peak by using a modified version of a previously proposed model and numerically solving sets of simultaneous differential equations governing the stages of TL phenomena (excitation, relaxation and heating). In the modified model, two additional electron trapping centers were incorporated in order to simulate accurately this glow curve. Computerized glow curve deconvolution (CGCD) analyses was carried out on the simulated glow peak in attempt to retrieve back the electron trapping center energies and to identify their respective peak positions. The outcome of this confirmed the peak to be possibly composite in nature comprising of three overlapping glow peaks at 288, 300 and 317oC with respective energy gaps of 1.70, 1.73 and 1.75eV. It is therefore further substantiated that this kind of temperature shift of peak with dose resulting from composite glow peaks is possible.
A Theoretical Analysis of Quasi-elastic Scattering of 7Li by 120Sn Using Various Nuclear Potentials
(Ankara : Ankara Üniversitesi, 2017) Aygün, Murat; Fen Fakültesi
The quasi-elastic scattering data of 7Li + 120Sn reaction at ELab = 19.5, 20.5, and 25.0 MeV incident energies have been reanalyzed within the framework of the optical model. In order to obtain the real potential, seven different nuclear potentials have been used. The imaginary potential has been assumed in Woods-Saxon form. The theoretical results have been compared with each other as well as the experimental data.
Thermal Fading Rates in LiF:Mg, Ti Main Thermoluminescence Peaks
(Ankara : Ankara Üniversitesi, 2017) Halimi, M.; Kadri, D.; Mokeddem, A.; Missoum, I.; Fen Fakültesi
Thermal fading (TF) is an important characteristic in choosing appropriate thermoluminescence (TL) materials for particular applications. TF is the process of reducing the capability of producing the response due to radiation exposure. The fading rate of LiF based thermoluminescent (TL) material depends on many experimental parameters such as storage temperature, readout mechanism, annealing and radiation type or time based on the storage time before or after radiation. The general aim of the present work is to investigate if the activation energy E, frequency factor s, maximum temperature, Tm and concentration, n values evaluated from the experimental thermal fading rates glow–curves through a computerized glow–curve deconvolution analysis (CGCD), can simulate the thermal fading glow-curves using a phenomenological model for LiF:Mg, Ti.
On the Role of ‘Reciprocal’ of the Strong Coupling Constant in Nuclear Structure
(Ankara : Ankara Üniversitesi, 2017) Seshavatharam, U. V. S.; Lakshminarayana, S.; Fen Fakültesi
Considering ‘reciprocal’ of the strong coupling constant as an index of strength of nuclear binding energy, it was reviewed the basics of nuclear binding energy and nuclear stability.
Assessment of Gama Dose Rates around Gaziantep City, Turkey
(Ankara : Ankara Üniversitesi, 2017) Zuhur, S.; Çeliktürk, D.; Yazıcı, A. N.; Öztürk, Z.; Fen Fakültesi
In this study, the measurements were performed 1 m above the ground in air and surface soils at certain points in the city of Gaziantep located at south of Turkey with a populatıon of 1.5 million. Air and soil measurements were carried out by portable detectors and gamma spectrometry system. As a result of measurements performed in the air, average annual effective dose of 66.81 µSv y-1 and gamma counting of 50.43 1 s-1 were found. On the other hand, as a result of gamma spectrometric analyses in the surface soil samples, average activity concentrations of 226Ra, 232Th and 40K were found to be 28.92, 29.49 and 255.30 Bq kg-1, respectively. Calculated absorbed dose rate and annual effective dose values depending on the activity concentrations, were found to be 38.45 nGy h-1 and 47.17 µSv y-1. When the measured values are compared with UNSCEAR 2000 report’s worldwide average value, our result is slightly lower than these values.
Modelling of Hottest Channels of VVER-1000 and VVER-1200 Nuclear Reactors by Using COBRA-TF and ZEBRA Thermal Hydraulic Codes
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Aktas Ozulus, Ö.; Ariman, N.; Iscen, F.; Kose, U.; Sengun, B.; Ergun, S.; Other; Other
The Coolant Boiling in Rod Arrays-Two Fluid (COBRA-TF) code is known as a best estimate code, used to perform thermal-hydraulic analyses for a light water reactor vessel. On the other hand, ZEBRA computer code is used to perform closed channel analysis, basically for educational purposes. In this study, the hottest channels of two Russian type nuclear reactors, namely VVER-1000 and VVER-1200, are modelled as one single channel by using COBRA-TF and ZEBRA thermal hydraulic codes. Both outputs of these two codes and operating conditions of hot channels of these different type reactors are compared. Clad outside temperatures, clad inside temperatures, fuel centreline temperatures, pressure drops, qualities and critical heat fluxes are main operating parameters that are compared. Besides, look-up table that is used to calculate critical heat flux for triangular nuclear fuel assembly pitch and outputs of COBRA-TF and ZEBRA codes are also compared. Some of the correction factors which are used on the look-up table results, if/when necessary are included for the calculations as well.
Volume Change in Organ At Risks and Its Effect on Cumulative Dose for Head and Neck Image Guided Radiotherapy – Deformable Image Registration
(Ankara : Ankara Üniversitesi, 2018) Can, S.; Karaçetin, D.; Meriç, N.; Fen Fakültesi
The purpose of this study is to evaluate the volume change of critical structures and its effect on cumulative dose by employing tighter CTV-to-PTV margins for target level II/III through a GPU-based (Geometric Processing Unit) deformable image registration. Ten H&N cases treated with simultaneous integrated boost (SIB) on a tomotherapy were retrospectively analysed (Accuracy Inc., CA). Each patient had one planning CT and daily kVCT images during the radiation treatment course. The standard – margin plan was generated by giving 3-mm margin to CTV1-3 and compared with the 0-mm margin plan for CTV2-3. However, 3 mm margin of PTV1 was saved to provide tumor coverage. The volume of right parotid gland was decreased significantly for patients who lost more weight during the treatment course. The mean volume reduction was 11.7 % with the range of 29.3- 1.3 % and 13.5 % with the range of 25.9- 5.7 % in right and left parotid glands respectively. The difference in the delivered dose regarding standard margin plan and 0- mm margin plan was ≈ 10 % for the cord, ≈ 8 % and ≈ 19 % for the left and right parotid gland respectively. IGRT is one of the most effective tools to correct set-up error and allow the planner to reduce margin. In addition, GPUbased 3D image framework was crucial for dose accumulation and evaluation of critical structures and targets. In this study, it was proved that acceptable cumulative dose for region of interest is consummated when connected with weekly kCVT guidance by using tighter CTV-to-PTV margins for level II and III targets for head and neck cases. On the other hand, change in volume did not affect the cumulative dose of critical structures when tighter CTV-to-PTV margin was employed.
Comparison of Surface Dose in Conventional and Digital Mammography and Forming the Statistical Mars Model for the Patients Who Had Mammography Examination in Compliance with the Mammography Examination Protocol
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Kavas, Y.; Demir, P.; Akyol, M.; Ateş, A.; Other; Other
Digital mammography equipment in the 230 and 180 conventional mammography equipment were shooting from the upper breast and the inner surface of the patient. Conventional mammography shooting in 50 patients were measured from four different points outside the breast and bottom surfaces in addition to them. This method for TLD 100 dosimetric measurements were made using a dosimeter. A total of 460 patients compared the results obtained by conventional mammography, digital mammography in shooting with the dose received from the upper breast and the inner surface was determined to be higher in this study. As well as breast density values detected during breast ultrasound study of the patient's breast size, used during the measurement kVp and mAs values are also included in the study. This study attempted to establish Mars statistical model using all data obtained.
Development of Attitude Scale for Nuclear Energy and Environmental Impacts: Stability and Reliability Study
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Güney, A.; Kaya, B.; Other; Other
This study, an attitude scale on the environmental effects of nuclear energy was developed. University students have been tried to determine their views on nuclear energy and environmental effects. The developed scale is a 5 point likert type attitude scale. Factor analysis was performed on the scale after the development phase of the scale and an adaptation model study was carried out on the scale items and dimensions. The scale was formed as a 37-item draft scale and 366 students were applied. In addition, students' relations with each other in terms of various variables have been examined. Within the scope of attitude scale reliability and reliability studies for nuclear energy and environmental effects, Cronbach Alpha reliability coefficient before analysis for general reliability was calculated as 0.534. When this value is small, a substance is removed from the scale (item 6) and the Cronbach Alpha reliability coefficient is calculated again. After analysis, it is calculated as 0,600. The results were evaluated at 95% confidence level.
Making Safety Analysis of PWR Pressure Vessel with Favor Code
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Yıldırım, A.; Ergün, Ş.; Other; Other
Reactor Pressure Vessels are the most important structures in view of keeping the integrity for nuclear power plants. Fracture Analysis of Vessels Oak Ridge (FAVOR) is a code which is used in USA for PWRs and BWRs to make probabilistic analysis to calculate both Pressure Vessel Crack Initiation Frequency and Pressure Vessel Failure Frequency, using thermal hydraulic data, material properties, flaw properties of pressure vessels for some kind of accidents and start up-close down situations. The analysis is concentrated on the belt line of the pressure vessels; this region is the most vulnerable region of the vessels because of the fast neutron fluence, and so material embrittlement increases and fracture toughness decreases in this region. In this study the flaw data files which were supplied have been changed by decreasing the density of flaws which have different sizes and the Crack Initiation Frequency and Failure Frequency of reactor vessels have been searched. Consequently it has been seen that these frequencies have lower values.
Determination of the Mass Attenuation Coefficient, Effective Atomic Number and Electron Density for Manganese Nano Hydroxyapatite by using 778-1457 keV Gamma Rays
(Ankara : Ankara Üniversitesi, 2018) Koksal, O. K.; Cengiz, E.; Apaydın, G.; Tozar, A.; Karahan, İ. H.; Fen Fakültesi
In this study, manganese nano substituted hydroxyapatite artificial bone powders (nMnHAp) have been investigated experimentally by means of mass attenuation coefficients, effective atomic numbers and electron densities. The samples were irradiated using 778 keV, 964 keV, 1085 keV, 1112 keV, 1408 keV and 1457 keV gamma photons from 152Eu source .The gamma photons from the source were counted by using a HPGe gamma-ray spectroscopy. The mass attenuation coefficients of the hydroxyapatites artificial bone powders (including hydroxyapatite without any substituted metal and real bone powder) were compared with each other. This study has been dealt with as a guide to medical field. Also the results have been evaluated in terms of the electron density and effective atomic number.
Application of SPECT / BT Simulations on Dynamic Resources by the Gate Software Oncological Imaging
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Aynacı, B.; Kuday, S.; Other; Other
Computerized tomography is a method of radiological diagnosis that allows us to arrive at a cross-sectional view of a region of the body under examination using X-rays. SPECT is a high-level 3D imaging of scintigraphy taken for the treatment of conditions such as radioactive materials, thyroid diseases, cancers, tumors, inflammatory diseases, etc. The fact that SPECT and CT are in one system gives spatial and pathological correlation of abnormal metabolic activity. This ensures that images are recorded together at the most efficient level and images are obtained from both systems with a single review. In this study, SPECT / CT simulations were performed for cylindrical voxel phantoms with near-real content using the GATE (PET & SPECT simulator library) created by the GEANT4 simulation software developed by the European Center for Nuclear Research (CERN). In the installations created in the virtual environment, activity differences, displacement and curtain effects of the tissues were investigated. Analyses were made with the ROOT software to obtain sinograms and dose curves. When the obtained data were analysed statistically, the results of these types of SPECT / CT imaging were found to be significant differences and the results were revealed.
Assessment of the Effect of Breathing Movements on the Skin Dose by Comparison of TLD Measurements and Plan Data in Breast Cancer Radiotherapy
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Ergün, D.; Arslan, S. Aytaç; Kaşkaş, A.; Other; Other
Breast cancer is the most common type of cancer in women. One out of every four women suffers from breast cancer in the world. İt is important for receiving adequate skin dose in breast cancer radiotherapy. The detailed information of dose in various depths of skin has a critical importance to determine new treatment techniques. If the skin dose homogeneity is not achieved, the risk of recurrence of disease is increased. Therefore, the homogeneity of dose distribution should be provided on the surface as it is in other parts of the breast. The aim of this study is to investigate the effect of respiratory movement and using the bolus on skin dose in breast cancer patients treated with helical tomotherapy. TLDs were placed on both the surface of the Alderson RANDO phantom's breast in eight points and on the projections of each points which is about 5 mm deep. A mechanism was used, which can be adjusted to the different frequency and amplitude values to simulate for measurements. The measurements were performed statically and dynamically (frequency=0.3 Hz, amplitude=5mm). Each measurement was repeated with and without bolus. The mean dose values were measured by using TLDs and bolus during respiratory at the surface and at 5 mm depth. The measured TLDs and calculated doses of TPS were compared, investigating the change of skin dose. The data were evaluated using the SPSS 20.0 statistical analysis program. According to the results, it is concluded that the respiratory movement is not a significant effect on the skin dose and it is not necessary to use the bolus. Besides, when TPS and TLD results were compared to each other; it is seen that, the estimation of skin dose of, TPS calculations was higher than TLDs measurements. This is clinically accepted. The results are in good agreement with literature values.
Quality Control and Performance Tests in Magnetic Resonance Imaging with the Direction of the Medical Physicist
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Asliyüce, İ.; Alpay, O.; Other; Other
The aim of the Magnetic Resonance Imaging (MRG) device is to provide the performance, image quality and patient safety. It was also compared with the quality control and performance tests conducted by the medical physicist in the American College of Radiology (ACR) guide. Quality control and performance tests were conducted with an authorized service engineer of the Philips medical device company on April 12, 2016. A 1.5 Tesla Philips Achieva/Intera MRI device and the phantoms compatible with this device were used at the Radiology Clinic of the OMÜ Faculty of Medicine. The resultant quality control and performance tests result in phantom images; by evaluating these images, no problem and image artefacts were observed in the MRI device concerned.
Investigation of the Effect of the Temporary Tissue Expander Used for Breast Reconstruction on Dose Distribution of Chest Wall Radiation
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Cibiceli, S.; Çatlı Dinç, S.; Erpolat, Ö. P.; Akyol, O.; Meriç, N.; Karahacioğlu, E.; Other; Other
The rate of breast reconstruction after mastectomy is increasing in women with breast cancer. At the breast reconstruction, silicone implants or temporary tissue expanders (TTEs) are placed instead of breast tissue taken during mastectomy. It is unclear how TTEs which contain metallic structures and filled with saline, affect dose distribution during RT. For this reason, so that optimum RT planning can be performed, the effect of metallic port in the Mentor TTE of dose distribution has been examined in our study. MOSFET, NanoDot OSLD and EBT3 film dosimetric methods were used in the measurements. As a result of single frontal irradiation with metallic port made of samarium cobalt magnet and stainless steel, removed from the TTE, the maximum dose reduction rate at the bottom of the metallic port is 29.65% with NanoDot OSLD. The maximum dose increase rate over the metallic port is 6.25% with NanoDot OSLD. At the results obtained with measurements of 6 MV photon energy on rando phantom using TTE and silicone implant; for 3DCRT and IMRT treatment techniques, dose increase of less than 5% was observed on the over, right and left side of the metallic port with all dosimetric methods and the planning data. Under the metallic port, the rate of dose changes determined below 4% for these two treatment techniques. While using 9 MeV and 12 MeV electron energy, each dosimetric method and the data obtained from the treatment plans are evaluated in measurements dose increments of 12.63% with 9 MeV electrons and 10.66% with 12 MeV electrons were observed on the over, right and left side of the metallic port. While examining the measurements, due to scattering caused by metallic port while there were doses increasing over the metallic port, there were doses decreasing under the metallic port. But according to the changes in dose at the doses prescribed by international dosimetric protocols (±%5) at our study the change in dose observed with 3DCRT and IMRT techniques at 6 MV photon energy appears to be not large enough to affect tumor treatment provided that the metallic port is introduced into TPS. At the 9 MeV and 12 MeV incision scar electron boost treatments, the metallic port significantly increased the skin dose even though it was introduced to TPS.
Physics and Engineering Aspects of High Power Electron Beam Dump for TARLA
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Erenler, D.; Aksoy, A.; Other; Other
Beam dumps are commonly used in particle accelerators, to absorb safely, stop and neutralize the high energetic particle beams without any harm to their organic and inorganic surroundings including the beam line itself. Thermal, nuclear and mechanical properties of the system are important for their operability and functionality. Depending on the energy and parameters of particles hitting the beam dump, the beam will transfer heat to the system, and may create radioactive material in beam dump. On the other hand, due to their complex structure, the components used to form beam dumps must be mechanically manufacturable, interchangeable and redundant. In this work, the design aspects of high power electron beam dump for the TARLA (Turkish Accelerator and Radiation Laboratory in Ankara) Facility -under construction at the Institute of Accelerator Technologies of Ankara University- were discussed. Several beam dump options were taken into account by focusing on nuclear interactions and radioactive properties of the dump. Various core materials such as aluminium, copper, carbon or alloys were compared by using FLUKA and Geant4 simulation tools. Shielding materials and geometries such as lead, concrete have been also taken into account.
Implementation of Nuclear Power Plants instead of “Kosovo A and B” Power Plants as the only Rescue of Coal Resources in the Republic of Kosovo
(Ankara : Ankara Üniversitesi, 2018) Beluli, V. M.; Fen Fakültesi
Kosovo as a state in Europe poses a serious problem of air pollution, due to the production of electricity from Kosovo A and Kosovo B coal fired-power plants, which use coal as fuel. Although Kosovo possesses large coal reserves, the monetary income from the production of electric power from the Coal-Fires Power Plants is very low and too much coal spending, which is a huge resource loss as well as a very valuable natural resource for future generations. Implementation of nuclear reactors may bring profits to this country and coal could have been sold as a raw material in various sectors, thus probably the state could earn about half a billion euros each year, this is due to the non-construction of a nuclear power plant. Kosovo is losing more than 2 billion amounts euro of coal-fired coal for 18 years due to coal-fired power plants. During 2017, Kosovo produced 5 300 000 MWh of electricity. Kosovo had also extracted 8 million tons of coal to produce electricity, while a nuclear reactor needs about 264.99 kg of 235U per year. The aim of this research is to highlight the increment of the price of electricity in the region of Kosovo and therefore standing as a big obstacle to foreign investment.
Determination of Total Gamma and Peak Efficiency of NaI (Tl) Detector
(Ankara Üniversitesi Nükleer Bilimler Enstitüsü, 2018) Güngür, D.; Kızılyer, N. Yavuzkanat; Yalçın, S.; Other; Other
NaI(Tl) detectors have high detection efficiency. NaI(Tl) is good at detecting low-level radiation sources. In this study, the total gamma and peak efficiency results of NaI (Tl) detector for both point and disk sources were investigated. Total efficiency peak obtained by Geant4-based Gate Simulation program consisted with the literature and the data obtained using the hybrid Monte Carlo method. Full energy peak and total efficiency were also compared with the experimental result.

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