Jonathan Walg, Yael Peleg, Anatoly Rodnianski, N. Hazenshprung, I. Orion
Changes in radioactive decay rates due to solar flares have attracted increasing scientific attention in recent decades. In previous studies we demonstrated that solar flares cause changes in the decay rate of 241Am, 222Rn, and 232Th. The change in the count rate of 54Mn due to solar flares, as observed by scholars at Purdue University in 2006, encouraged us to repeat the measurements. In addition, we measured gamma radiation count rates of 57Co that undergoes electron capture, as in 54Mn decay. Our new measurements indicate that there is a delay of about five days between the solar flare occurrence and the decrease in 54Mn count rates. Also, we conclude that in the 54Mn study of 2006 there was a delay between the solar flares and the resulting count rate dips. With regard to the 57Co counting system, we measured about a seven-day delay between the occurrence of solar flares and the count rate dips. We conclude that 54Mn and 57Co interact with neutrinos that originate during solar flares.
{"title":"Effect of solar flares on 54Mn and 57Co radioactive decay constants performance","authors":"Jonathan Walg, Yael Peleg, Anatoly Rodnianski, N. Hazenshprung, I. Orion","doi":"10.2298/ntrp2103219w","DOIUrl":"https://doi.org/10.2298/ntrp2103219w","url":null,"abstract":"Changes in radioactive decay rates due to solar flares have attracted increasing scientific attention in recent decades. In previous studies we demonstrated that solar flares cause changes in the decay rate of 241Am, 222Rn, and 232Th. The change in the count rate of 54Mn due to solar flares, as observed by scholars at Purdue University in 2006, encouraged us to repeat the measurements. In addition, we measured gamma radiation count rates of 57Co that undergoes electron capture, as in 54Mn decay. Our new measurements indicate that there is a delay of about five days between the solar flare occurrence and the decrease in 54Mn count rates. Also, we conclude that in the 54Mn study of 2006 there was a delay between the solar flares and the resulting count rate dips. With regard to the 57Co counting system, we measured about a seven-day delay between the occurrence of solar flares and the count rate dips. We conclude that 54Mn and 57Co interact with neutrinos that originate during solar flares.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68546578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Kartalović, Sasa Djekic, Sasa Djekic, Dušan P. Nikezić, Uzahir R. Ramadani
The paper considers the application of nuclear magnetic resonance to measure fluid flow. The paper is of an experimental nature. Flowmeter based on nuclear magnetic resonance is extremely precise. The combined measurement uncertainty can be 0.1 %. Such a value of measurement uncertainty indicates that it is a matter of a deterministic and not of a stochastic quantity. This high degree of reliability of the method is theoretically and mathematically described. The paper presents a measurement scheme for flow measurement. Water flow measurement was performed on the principle of nuclear magnetic resonance and on the basis of tritiated water (which is considered to be the most accurate classical method). The obtained results show that the measurement of flow based on nuclear magnetic resonance is more accurate (especially at higher flow). This is explained by the higher inertial mass of HTO tritiated water molecules than the standard H2O water mass and the possible transition of tritiated water to H3HeO. In this way, it has been proven that tracing water based on nuclear magnetic resonance is the only real tracing of water by water. The obtained results shows that tracing water with tritiated or heavy water is not tracing water by water which is explained by different inertial masses.
{"title":"Possibility of application nuclear magnetic resonance to measure fluid flow","authors":"N. Kartalović, Sasa Djekic, Sasa Djekic, Dušan P. Nikezić, Uzahir R. Ramadani","doi":"10.2298/ntrp210614017k","DOIUrl":"https://doi.org/10.2298/ntrp210614017k","url":null,"abstract":"The paper considers the application of nuclear magnetic resonance to measure fluid flow. The paper is of an experimental nature. Flowmeter based on nuclear magnetic resonance is extremely precise. The combined measurement uncertainty can be 0.1 %. Such a value of measurement uncertainty indicates that it is a matter of a deterministic and not of a stochastic quantity. This high degree of reliability of the method is theoretically and mathematically described. The paper presents a measurement scheme for flow measurement. Water flow measurement was performed on the principle of nuclear magnetic resonance and on the basis of tritiated water (which is considered to be the most accurate classical method). The obtained results show that the measurement of flow based on nuclear magnetic resonance is more accurate (especially at higher flow). This is explained by the higher inertial mass of HTO tritiated water molecules than the standard H2O water mass and the possible transition of tritiated water to H3HeO. In this way, it has been proven that tracing water based on nuclear magnetic resonance is the only real tracing of water by water. The obtained results shows that tracing water with tritiated or heavy water is not tracing water by water which is explained by different inertial masses.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68547805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The results of engineering an intelligent preamplifier for HPGe gamma-detectors are presented. An intelligent preamplifier is a low-noise, high-speed resistive feedback charge-sensitive preamplifier with a built-in microcontroller and additional units that enable control of preamplifier and detector parameters. It also allows to manage performance of the internal testing pulser, sensor of liquid nitrogen level in Dewar, humidity, pressure and temperature sensors in a sealed preamplifier section. Intelligent preamplifier operation, setup and parameter measurements are controlled by a software.
{"title":"Development of intelligent preamplifier for semiconductor detectors","authors":"F. V. Kondratjev, S. V. Litvinsky, S. Pohuliai","doi":"10.2298/ntrp201109008k","DOIUrl":"https://doi.org/10.2298/ntrp201109008k","url":null,"abstract":"The results of engineering an intelligent preamplifier for HPGe gamma-detectors are presented. An intelligent preamplifier is a low-noise, high-speed resistive feedback charge-sensitive preamplifier with a built-in microcontroller and additional units that enable control of preamplifier and detector parameters. It also allows to manage performance of the internal testing pulser, sensor of liquid nitrogen level in Dewar, humidity, pressure and temperature sensors in a sealed preamplifier section. Intelligent preamplifier operation, setup and parameter measurements are controlled by a software.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68545274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Abbas, M. El-Khatib, S. Badawi, T. M. Alabsy, M. Hagag
Polymer composites of Polyvinyl chloride (PVC) were loaded up with micro and nano PbO/CuO particles. The added percentage of each by mass was [10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.%] plus 40 wt.% of mixed composite (20 wt.% CuO+ 20 wt.% PbO). The mass and linear attenuation coefficients of the investigated composites were measured as a function of ?-ray energies going from 59.53 keV to 1408.01 keV utilizing standard radioactive point sources. To confirm the validity of these results the attenuation coefficients for bulk composites (PVC+PbO and PVC+CuO) were calculated by using XCOM software. The results were in good agreement with the values obtained from experimental work. On comparing the attenuation coefficients of the different composites it was found that those loaded with either nano PbO or CuO have higher values than those loaded with bulk sizes with the same percentage. Also, samples loaded with nano PbO have the highest attenuation coefficients even on comparing with (20 wt.% CuO+ 20 wt.% PbO), especially in the energy region below 1 MeV, but for greater energies, the values become very closed. The investigation of the mechanical properties of such composites due to the injection of bulk and nano metals reveals that tensile strength and Young?s modulus of PVC nanocomposite sheets were notably increased with the increasing concentration of CuO and PbO nanoparticles. CuO nanocomposite showed the highest values of flexural strength, toughness, and tensile strength among all the fabricated nanocomposite sheets.
{"title":"Gamma attenuation through nano lead - nano copper PVC composites","authors":"M. Abbas, M. El-Khatib, S. Badawi, T. M. Alabsy, M. Hagag","doi":"10.2298/ntrp210110001a","DOIUrl":"https://doi.org/10.2298/ntrp210110001a","url":null,"abstract":"Polymer composites of Polyvinyl chloride (PVC) were loaded up with micro and nano PbO/CuO particles. The added percentage of each by mass was [10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.%] plus 40 wt.% of mixed composite (20 wt.% CuO+ 20 wt.% PbO). The mass and linear attenuation coefficients of the investigated composites were measured as a function of ?-ray energies going from 59.53 keV to 1408.01 keV utilizing standard radioactive point sources. To confirm the validity of these results the attenuation coefficients for bulk composites (PVC+PbO and PVC+CuO) were calculated by using XCOM software. The results were in good agreement with the values obtained from experimental work. On comparing the attenuation coefficients of the different composites it was found that those loaded with either nano PbO or CuO have higher values than those loaded with bulk sizes with the same percentage. Also, samples loaded with nano PbO have the highest attenuation coefficients even on comparing with (20 wt.% CuO+ 20 wt.% PbO), especially in the energy region below 1 MeV, but for greater energies, the values become very closed. The investigation of the mechanical properties of such composites due to the injection of bulk and nano metals reveals that tensile strength and Young?s modulus of PVC nanocomposite sheets were notably increased with the increasing concentration of CuO and PbO nanoparticles. CuO nanocomposite showed the highest values of flexural strength, toughness, and tensile strength among all the fabricated nanocomposite sheets.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68545433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. M. Radmilovic-Radjenovic, Z. Nikitovic, M. Radjenovic
Surface roughness represents the measure of the irregularities on the surface contributing to the local field enhancement. The traditional Fowler-Nordheim equation established for perfectly planar surfaces is not suitable for describing emission from rough surfaces. Instead, it is more appropriate to use the equation that accounts for the field enhancement factor describing the effect of the surface morphology. In superconducting radio frequency cavities field emission may occur in the irises and the tips on the cavity surface may act as an emitter leading to the high electric field. For this study, calculations for hemispherical, cylindrical, and conical tips have been performed by using a multiphysics software package COMSOL. The focus was put on the dependence of the field enhancement factor on the shape and the radius of the protrusions. The electric field strength and the current density increase with increasing the root mean square average of the profile heights due to field enhancement at the cavity irises. The lowest value of the electric field has been achieved for the hemisphere. The calculated values for the field enhancement factors are consistent with the data from the literature, in which case the protrusion may represent a small local bump on the surface of a superconducting cavity. Based on the fit of the results, presented here, the relation between the enhancement factor and the radius has been suggested. The accurate estimation of the field emission may play a crucial role in the design of accelerators and other technological applications with requirements of very high precision.
{"title":"Studies of enhanced field emission relevant to high field superconducting radio frequency devices","authors":"D. M. Radmilovic-Radjenovic, Z. Nikitovic, M. Radjenovic","doi":"10.2298/ntrp210121007r","DOIUrl":"https://doi.org/10.2298/ntrp210121007r","url":null,"abstract":"Surface roughness represents the measure of the irregularities on the surface contributing to the local field enhancement. The traditional Fowler-Nordheim equation established for perfectly planar surfaces is not suitable for describing emission from rough surfaces. Instead, it is more appropriate to use the equation that accounts for the field enhancement factor describing the effect of the surface morphology. In superconducting radio frequency cavities field emission may occur in the irises and the tips on the cavity surface may act as an emitter leading to the high electric field. For this study, calculations for hemispherical, cylindrical, and conical tips have been performed by using a multiphysics software package COMSOL. The focus was put on the dependence of the field enhancement factor on the shape and the radius of the protrusions. The electric field strength and the current density increase with increasing the root mean square average of the profile heights due to field enhancement at the cavity irises. The lowest value of the electric field has been achieved for the hemisphere. The calculated values for the field enhancement factors are consistent with the data from the literature, in which case the protrusion may represent a small local bump on the surface of a superconducting cavity. Based on the fit of the results, presented here, the relation between the enhancement factor and the radius has been suggested. The accurate estimation of the field emission may play a crucial role in the design of accelerators and other technological applications with requirements of very high precision.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68546149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Dimović, I. Jelić, V. Stanic, Andrea Kojic, P. Bozovic
The aim of the study was to assess Cs+ ions transport phenomena from solidified spent ion exchange resin by mathematical modeling. The experimental results comparison was obtained by Hespe?s Standard Leaching Method. For the leaching prediction rate as a time function diffusion and semi-empirical models were used. Due to the presence of spent ion exchange resin, the cement matrix absorbed a larger amount of water, swelled, and degraded. This phenomenon caused a significantly lower value of mechanical resistance to pressure. Also, through the increase of bentonite and zeolite content, the cement matrix decreased its mechanical resistance. The retention of cesium ions in the cement matrix was low and they were leached during the early phase of the investigation. The diffusion coefficient, De, decreased by three orders of magnitude with the addition of zeolite and bentonite in the cement matrix. Linear regression of experimental Cs+ leaching results under static conditions displayed that the semi-empirical parameter K3 absolute values were one to two orders of magnitude lower than the absolute values of the parameters K2 and K1. Therefore, the contribution of matrix dissolution to the total radionuclides transport was irrelevant to the prevailing share of diffusion and surface washing processes.
{"title":"Mathematical modeling of Cs+ transport phenomena from solidified spent ion exchange resin","authors":"S. Dimović, I. Jelić, V. Stanic, Andrea Kojic, P. Bozovic","doi":"10.2298/ntrp210128016d","DOIUrl":"https://doi.org/10.2298/ntrp210128016d","url":null,"abstract":"The aim of the study was to assess Cs+ ions transport phenomena from solidified spent ion exchange resin by mathematical modeling. The experimental results comparison was obtained by Hespe?s Standard Leaching Method. For the leaching prediction rate as a time function diffusion and semi-empirical models were used. Due to the presence of spent ion exchange resin, the cement matrix absorbed a larger amount of water, swelled, and degraded. This phenomenon caused a significantly lower value of mechanical resistance to pressure. Also, through the increase of bentonite and zeolite content, the cement matrix decreased its mechanical resistance. The retention of cesium ions in the cement matrix was low and they were leached during the early phase of the investigation. The diffusion coefficient, De, decreased by three orders of magnitude with the addition of zeolite and bentonite in the cement matrix. Linear regression of experimental Cs+ leaching results under static conditions displayed that the semi-empirical parameter K3 absolute values were one to two orders of magnitude lower than the absolute values of the parameters K2 and K1. Therefore, the contribution of matrix dissolution to the total radionuclides transport was irrelevant to the prevailing share of diffusion and surface washing processes.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68546346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Apostolakopoulos, N. Kržanović, P. Božović, K. Stanković, Luka S. Perazić
The aim of this paper is to examine the energy and angular responses of thermoluminescent (LiF:Mg,Ti and LiF:Mg,Cu,P) and optically stimulated luminescent (Al2O3:C) dosimeters with experimental measurements and Monte Carlo simulations. Nine radiation qualities, with mean energies ranging from 33 keV to 1.25 MeV, and five angles of incidence, between 0? and 80?, were used to conduct this analysis. The IEC 62387:2020 international radiation protection standard was used as the dosimeter response measure of quality. The experimental and simulated data exhibit that the dosimeter responses meet the standard's criteria, with certain exceptions on lower energies.
{"title":"Comparison of experimental and simulated responses of TL and OSL dosimeters in poly-energetic and multi-directional photon radiation fields","authors":"F. Apostolakopoulos, N. Kržanović, P. Božović, K. Stanković, Luka S. Perazić","doi":"10.2298/ntrp2104329a","DOIUrl":"https://doi.org/10.2298/ntrp2104329a","url":null,"abstract":"The aim of this paper is to examine the energy and angular responses of thermoluminescent (LiF:Mg,Ti and LiF:Mg,Cu,P) and optically stimulated luminescent (Al2O3:C) dosimeters with experimental measurements and Monte Carlo simulations. Nine radiation qualities, with mean energies ranging from 33 keV to 1.25 MeV, and five angles of incidence, between 0? and 80?, were used to conduct this analysis. The IEC 62387:2020 international radiation protection standard was used as the dosimeter response measure of quality. The experimental and simulated data exhibit that the dosimeter responses meet the standard's criteria, with certain exceptions on lower energies.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"16 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68546970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The applicability of a simple Monte Carlo gamma transmission model was investigated by characterizing the mass attenuation coefficient, mean free path, and half-value layer for six glass sample simulants of the PbO-Li2O-B2O3 system previously prepared by others. The mass attenuation coefficients were calculated and compared with those of XCOM and the available experimental data for twenty gamma energy lines from 0.107 MeV to 7.12 MeV, and good agreement was obtained. The effects of PbO concentration on the simulated values of mass attenuation coefficient, mean free path, and half-value layer, were calculated and compared with available experimental data in the gamma energy range 0.356-1.332 MeV, and good agreement was found. The glass sample with the optimal gamma shielding for all considered gamma energies was the sample with the chemical formula Pb3B4O9. On the one hand, the Monte Carlo results confirm the applicability of the proposed model for performing additional calculations of photon attenuation properties for different glass compositions, and on the other hand, considering the energy range of gamma-ray photons in a reactor during uranium fission, 0.10-10 MeV, the results suggest the use of the studied glass samples as optical shielding windows in nuclear reactors.
{"title":"Monte Carlo gamma transmission model for characterization of multi-gamma shielding parameters of some heavy metal oxide glasses","authors":"N. Elsheikh","doi":"10.2298/ntrp2104338e","DOIUrl":"https://doi.org/10.2298/ntrp2104338e","url":null,"abstract":"The applicability of a simple Monte Carlo gamma transmission model was investigated by characterizing the mass attenuation coefficient, mean free path, and half-value layer for six glass sample simulants of the PbO-Li2O-B2O3 system previously prepared by others. The mass attenuation coefficients were calculated and compared with those of XCOM and the available experimental data for twenty gamma energy lines from 0.107 MeV to 7.12 MeV, and good agreement was obtained. The effects of PbO concentration on the simulated values of mass attenuation coefficient, mean free path, and half-value layer, were calculated and compared with available experimental data in the gamma energy range 0.356-1.332 MeV, and good agreement was found. The glass sample with the optimal gamma shielding for all considered gamma energies was the sample with the chemical formula Pb3B4O9. On the one hand, the Monte Carlo results confirm the applicability of the proposed model for performing additional calculations of photon attenuation properties for different glass compositions, and on the other hand, considering the energy range of gamma-ray photons in a reactor during uranium fission, 0.10-10 MeV, the results suggest the use of the studied glass samples as optical shielding windows in nuclear reactors.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68547116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aimed to investigate the different positioning of the patient in left and right lateral position during lumbar spine radiography and its effects on effective dose and absorbed dose for selected organs. The study was performed on a Siemens Multix/Vertix X-ray unit using Agfa's computer radiography system. Two anthropomorphic phantoms (PBU 60 and RS 113T) were imaged in both lateral projections with a tube voltage from 79 kV to 90 kV. The dose was measured with a DAP meter placed under the collimator of the X-ray unit. The effective dose and absorbed dose for selected organs were calculated using the Monte Carlo simulation programme PCXMC 2.0. Based on Monte Carlo simulation calculations, the results of effective dose on a PBU 60 phantom showed a decrease of 15.2%, while the decrease in effective dose on a RS 113T phantom was 14.2% in favour of the right lateral projection. An absorbed organ dose to selected organs showed a significant dose reduction for lymph nodes, pancreas, small intestine, spleen, and stomach in favour of this projection. Based on the results, we can conclude that right lateral projection should be the method of choice when imaging the lumbar spine in the lateral projection.
{"title":"Effect of different phantom positions in lateral lumbar spine radiography on effective dose and absorbed dose to selected organs","authors":"N. Mekiš, E. Alukić","doi":"10.2298/ntrp2104364m","DOIUrl":"https://doi.org/10.2298/ntrp2104364m","url":null,"abstract":"This study aimed to investigate the different positioning of the patient in left and right lateral position during lumbar spine radiography and its effects on effective dose and absorbed dose for selected organs. The study was performed on a Siemens Multix/Vertix X-ray unit using Agfa's computer radiography system. Two anthropomorphic phantoms (PBU 60 and RS 113T) were imaged in both lateral projections with a tube voltage from 79 kV to 90 kV. The dose was measured with a DAP meter placed under the collimator of the X-ray unit. The effective dose and absorbed dose for selected organs were calculated using the Monte Carlo simulation programme PCXMC 2.0. Based on Monte Carlo simulation calculations, the results of effective dose on a PBU 60 phantom showed a decrease of 15.2%, while the decrease in effective dose on a RS 113T phantom was 14.2% in favour of the right lateral projection. An absorbed organ dose to selected organs showed a significant dose reduction for lymph nodes, pancreas, small intestine, spleen, and stomach in favour of this projection. Based on the results, we can conclude that right lateral projection should be the method of choice when imaging the lumbar spine in the lateral projection.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68547686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work addresses the problem of propagating uncertainty from group-wise neutron cross-sections to the results of neutronics diffusion calculations. Automatic differentiation based on dual number arithmetic was applied to uncertainty propagation in the framework of local sensitivity analysis. As an illustration, we consider a two-group diffusion problem in an infinite medium, which has a solution in a closed form. We employ automatic differentiation in conjunction with the sandwich formula for uncertainty propagation in three ways. Firstly, by evaluating the analytical expression for the multiplication factor using dual number arithmetic. Then, by solving the diffusion problem with the power iteration algorithm and the algebra of dual matrices. Finally, automatic differentiation is used to calculate the partial derivatives of the production and loss operators in the perturbation formula from the adjoint-weighted technique. The numerical solution of the diffusion problem is verified against the analytical formulas and the results of the uncertainty calculations are compared with those from the global sensitivity analysis approach. The uncertainty values obtained in this work differ from values given in the literature by less than 1?10?5.
{"title":"Dual number automatic differentiation as applied to two-group cross-section uncertainty propagation","authors":"P. Bokov, D. Botes, S. Groenewald","doi":"10.2298/ntrp2102107b","DOIUrl":"https://doi.org/10.2298/ntrp2102107b","url":null,"abstract":"This work addresses the problem of propagating uncertainty from group-wise neutron cross-sections to the results of neutronics diffusion calculations. Automatic differentiation based on dual number arithmetic was applied to uncertainty propagation in the framework of local sensitivity analysis. As an illustration, we consider a two-group diffusion problem in an infinite medium, which has a solution in a closed form. We employ automatic differentiation in conjunction with the sandwich formula for uncertainty propagation in three ways. Firstly, by evaluating the analytical expression for the multiplication factor using dual number arithmetic. Then, by solving the diffusion problem with the power iteration algorithm and the algebra of dual matrices. Finally, automatic differentiation is used to calculate the partial derivatives of the production and loss operators in the perturbation formula from the adjoint-weighted technique. The numerical solution of the diffusion problem is verified against the analytical formulas and the results of the uncertainty calculations are compared with those from the global sensitivity analysis approach. The uncertainty values obtained in this work differ from values given in the literature by less than 1?10?5.","PeriodicalId":49734,"journal":{"name":"Nuclear Technology & Radiation Protection","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68545915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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