Pub Date : 2023-06-15DOI: 10.15392/2319-0612.2023.2251
Farida Lolila, Mohamed Mazunga
In this study, pre-mining ambient gamma dose equivalent rates at 1 m above the ground were measured using a Gamma-Scout portable radiation survey meter at two sites, A and B, around the Manyoni uranium deposit in Tanzania. Site A is expected to receive mine-dust particles with an aerodynamic diameter ≤ 10 µm (PM10) that have mean annual ground level concentrations (AGLC) ≥ 10% of the WHO air quality guideline limit of 20 µg/m3, and Site B is expected to receive PM10 with a mean AGLC ≥ 20 µg/m3. At Site A, the average of the ambient dose equivalent rates was 0.25 ± 0.03 µSv/h and ranged from 0.08 to 0.69 µSv/h. Similarly, at Site B, the average of the ambient dose equivalent rates was 0.23 ± 0.02 µSv/h and ranged from 0.12 to 0.34 µSv/h. The effect of the local geology on the measured dose rates was also presented. Since the ambient dose equivalent is an operational quantity for area monitoring, the results of this study will be very useful for comparing with the operational monitoring results of Sites A and B once uranium mining starts in Manyoni. This can help mine operators and regulatory agencies keep an eye on any rise in background radiation so they can take the necessary measures to safeguard locals and the environment from the harmful effects of ionising radiation.
{"title":"Measurements of the ambient dose equivalent rates around the Manyoni uranium deposit in Tanzania","authors":"Farida Lolila, Mohamed Mazunga","doi":"10.15392/2319-0612.2023.2251","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2251","url":null,"abstract":"In this study, pre-mining ambient gamma dose equivalent rates at 1 m above the ground were measured using a Gamma-Scout portable radiation survey meter at two sites, A and B, around the Manyoni uranium deposit in Tanzania. Site A is expected to receive mine-dust particles with an aerodynamic diameter ≤ 10 µm (PM10) that have mean annual ground level concentrations (AGLC) ≥ 10% of the WHO air quality guideline limit of 20 µg/m3, and Site B is expected to receive PM10 with a mean AGLC ≥ 20 µg/m3. At Site A, the average of the ambient dose equivalent rates was 0.25 ± 0.03 µSv/h and ranged from 0.08 to 0.69 µSv/h. Similarly, at Site B, the average of the ambient dose equivalent rates was 0.23 ± 0.02 µSv/h and ranged from 0.12 to 0.34 µSv/h. The effect of the local geology on the measured dose rates was also presented. Since the ambient dose equivalent is an operational quantity for area monitoring, the results of this study will be very useful for comparing with the operational monitoring results of Sites A and B once uranium mining starts in Manyoni. This can help mine operators and regulatory agencies keep an eye on any rise in background radiation so they can take the necessary measures to safeguard locals and the environment from the harmful effects of ionising radiation.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89074082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-14DOI: 10.15392/2319-0612.2023.2225
I. Garcia, Jeovana Santos Ferreira, Eric Matos Macedo, Marcos Vinicius Teixeira Navarro, José Guilherme Pereira Peixoto
For the new metrological challenges of an increasingly digitized world, several countries are developing applications and infrastructure for Digital Calibration Certificates – DCC, researching the comparability of real and virtual measurements. Objective: to map the processes and risks related to the digital transformation of X-rays air kerma calibration. The Failure Mode and Effect Analysis - FMEA was used to quantify risks and is widely used in the aviation and automotive industry due to its reliability. The results presented a conceptual model for calibrating ionizing radiation quantities in the framework of new technologies and calibration 4.0 and comparing processes and risks. The conceptual model of calibration 4.0 comprises three main parts: a transmitter, the 4.0 communication network, and a receiver. Intelligent devices with configurations enable calibration data transfers by radio-frequency messaging in all these parts. Comparing risks in contemporary and calibration 4.0 processes, a slight reduction in the total risk can be observed. But new risks are unique to the 4.0 model, all with maximum severity, and how to mitigate them is still unknown. It is also possible to estimate that artificial intelligence and automation can significantly reduce measurement risks, identification, and error in the analysis and use of calibration certificates.
{"title":"Mapping of processes and risks in the digital transformation in metrology of ionizing radiation, a case study in X-rays air kerma calibration","authors":"I. Garcia, Jeovana Santos Ferreira, Eric Matos Macedo, Marcos Vinicius Teixeira Navarro, José Guilherme Pereira Peixoto","doi":"10.15392/2319-0612.2023.2225","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2225","url":null,"abstract":"For the new metrological challenges of an increasingly digitized world, several countries are developing applications and infrastructure for Digital Calibration Certificates – DCC, researching the comparability of real and virtual measurements. Objective: to map the processes and risks related to the digital transformation of X-rays air kerma calibration. The Failure Mode and Effect Analysis - FMEA was used to quantify risks and is widely used in the aviation and automotive industry due to its reliability. The results presented a conceptual model for calibrating ionizing radiation quantities in the framework of new technologies and calibration 4.0 and comparing processes and risks. The conceptual model of calibration 4.0 comprises three main parts: a transmitter, the 4.0 communication network, and a receiver. Intelligent devices with configurations enable calibration data transfers by radio-frequency messaging in all these parts. Comparing risks in contemporary and calibration 4.0 processes, a slight reduction in the total risk can be observed. But new risks are unique to the 4.0 model, all with maximum severity, and how to mitigate them is still unknown. It is also possible to estimate that artificial intelligence and automation can significantly reduce measurement risks, identification, and error in the analysis and use of calibration certificates.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87734866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-14DOI: 10.15392/2319-0612.2023.2244
S. Aquino, José Eduardo Alves de Lima, S. I. Borrely
This work aimed to analyze the fungal contamination of air-conditioning filter waste (n=15) as an indicator of Quality Air Indoor from different car models in São Paulo city in São Paulo State, Brazil, during the period from October 2018 to July 2019. Three different treatments were used for the decontamination of car air conditioning filters, such as mechanical vacuum cleaning (I), vacuum cleaning and use of sanitizing product (II), and sanitizing product associated with radiation treatment at a dose of 17 kGy (III). After the treatments, microbiological analyses were performed and samples were plated in Petri dishes containing Sabouraud agar transferred by Swabs, and incubated for 7 days at 25 °C. The Petri dishes were stored in a standard Biochemical Oxygen Demand incubator, for the growth of fungal cultures. After incubation, the fungal cultures were evaluated, and the fungal counting was expressed in unit-forming colonies (UFC) and frequency in samples (%). The fungi were examined by lactophenol blue solution staining for microscopy. All samples of treatment I and II were contaminated with various fungal genera and high bioburden, namely (treatment I) Alternaria alternata, Aspergillus flavus, A. niger, Cladosporium spp., Fusarium spp., Mucor spp., Nigrospora spp., Not Sporulated Fungi (NSF), Penicillium spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp. and yeasts. Treatment II showed Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. ochraceus, Cladosporium spp., Mucor spp., NSF, Penicillium spp., Phoma spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp., and yeasts. Treatment III presented NSF and yeasts, with 80% of material decontamination.
{"title":"Combined application of gamma radiation, cleaning and chemical sanitizers in decontamination of vehicle air conditioning filters","authors":"S. Aquino, José Eduardo Alves de Lima, S. I. Borrely","doi":"10.15392/2319-0612.2023.2244","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2244","url":null,"abstract":"This work aimed to analyze the fungal contamination of air-conditioning filter waste (n=15) as an indicator of Quality Air Indoor from different car models in São Paulo city in São Paulo State, Brazil, during the period from October 2018 to July 2019. Three different treatments were used for the decontamination of car air conditioning filters, such as mechanical vacuum cleaning (I), vacuum cleaning and use of sanitizing product (II), and sanitizing product associated with radiation treatment at a dose of 17 kGy (III). After the treatments, microbiological analyses were performed and samples were plated in Petri dishes containing Sabouraud agar transferred by Swabs, and incubated for 7 days at 25 °C. The Petri dishes were stored in a standard Biochemical Oxygen Demand incubator, for the growth of fungal cultures. After incubation, the fungal cultures were evaluated, and the fungal counting was expressed in unit-forming colonies (UFC) and frequency in samples (%). The fungi were examined by lactophenol blue solution staining for microscopy. All samples of treatment I and II were contaminated with various fungal genera and high bioburden, namely (treatment I) Alternaria alternata, Aspergillus flavus, A. niger, Cladosporium spp., Fusarium spp., Mucor spp., Nigrospora spp., Not Sporulated Fungi (NSF), Penicillium spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp. and yeasts. Treatment II showed Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. ochraceus, Cladosporium spp., Mucor spp., NSF, Penicillium spp., Phoma spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp., and yeasts. Treatment III presented NSF and yeasts, with 80% of material decontamination.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90519141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.15392/2319-0612.2023.2142
G. G. Nascimento, C. Silva, V. Campos, L. Campos
Radiation dosimetry has the purpose of quantifying the dose received by the occupationally exposed individual. The device used in this process is called a dosimeter, the dosimeter can be used in different situations, for example, the dosimeter used to quantify the dose received in the fingers is the ring model dosimeter, for the extremity, which is the focus of this work. In Brazil, we still do not have standards for the calibration of extremity dosimeters, therefore, in this work, the CASEC recommendations were used, adapted for extremity dosimetry. For a dosimeter to be used in its respective routine, it must present results within some pre-established limits in reference standards. For this purpose, energy dependence and angular dependence tests were carried out. To calibrate the LiF:Mg,Ti thermoluminescent dosimeters, a phantom rod was used. The phantom rod has the function of simulating the region of interest, in the case of this work, the fingers. The dosimeters were irradiated in the magnitude Hp(0.07), with the doses and energies recommended by the CASEC standard. The aim of this work is to characterize end dosimeters in the ring model with LiF:Mg,Ti detectors.
{"title":"Assessment of energy and angular dependence of LiF:Mg,Ti dosimeters irradiated in the quantity Hp(0.07)","authors":"G. G. Nascimento, C. Silva, V. Campos, L. Campos","doi":"10.15392/2319-0612.2023.2142","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2142","url":null,"abstract":"Radiation dosimetry has the purpose of quantifying the dose received by the occupationally exposed individual. The device used in this process is called a dosimeter, the dosimeter can be used in different situations, for example, the dosimeter used to quantify the dose received in the fingers is the ring model dosimeter, for the extremity, which is the focus of this work. In Brazil, we still do not have standards for the calibration of extremity dosimeters, therefore, in this work, the CASEC recommendations were used, adapted for extremity dosimetry. For a dosimeter to be used in its respective routine, it must present results within some pre-established limits in reference standards. For this purpose, energy dependence and angular dependence tests were carried out. To calibrate the LiF:Mg,Ti thermoluminescent dosimeters, a phantom rod was used. The phantom rod has the function of simulating the region of interest, in the case of this work, the fingers. The dosimeters were irradiated in the magnitude Hp(0.07), with the doses and energies recommended by the CASEC standard. The aim of this work is to characterize end dosimeters in the ring model with LiF:Mg,Ti detectors.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83204252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-06DOI: 10.15392/2319-0612.2023.2183
F. Lópes, R. Rocha, E. Munhoz, F. C. Trigo, V. Feijó, M. Fernandes, T. C. de Paula, L. G. Padilha Filho, G. Araújo
Irradiation is a technique used in hemotherapy to functionally inactivateviable lymphocytes, in cellular blood components, to reduce the risk of Transfusion-associated Graft-versus-Host Disease (AT-GVHD), is rare but letal. One way to avoid it is to irradiate blood componentes in situations such as: intrauterine transfusion, newborns, patients receiving immunosuppressive therapy in bone marrow transplantation. Thus, it is extremely important that blood component is irradiated and, above all, ensure that the minimum dose is 25 Gy.The blood policy in Brazil is implemented through laws and normative decrees, giving rise to a legal system that underpins the actions of hemotherapy services. In order to correct verify absorbed doses and the quality assurance process as well as the safety for the irradiator operators we describe in this paper a several of physical measurements that is mandatory to support a physicist to evaluate the quality assurance during and after the irradiation process. The results obtained from this physical measurements provided a guarantee of proper radiation dose used in hemotherapy as well as methods and procedures applied to protect the patient, employees and general public due to procedure of blood irradiation accordling the Technical Regulation of Hemotherapy Procedures of the National Health Surveillance Agency (ANVISA) and safety regulations by National Nuclear Energy Commission (CNEN).
{"title":"Quality control in blood irradiation","authors":"F. Lópes, R. Rocha, E. Munhoz, F. C. Trigo, V. Feijó, M. Fernandes, T. C. de Paula, L. G. Padilha Filho, G. Araújo","doi":"10.15392/2319-0612.2023.2183","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2183","url":null,"abstract":"Irradiation is a technique used in hemotherapy to functionally inactivateviable lymphocytes, in cellular blood components, to reduce the risk of Transfusion-associated Graft-versus-Host Disease (AT-GVHD), is rare but letal. One way to avoid it is to irradiate blood componentes in situations such as: intrauterine transfusion, newborns, patients receiving immunosuppressive therapy in bone marrow transplantation. Thus, it is extremely important that blood component is irradiated and, above all, ensure that the minimum dose is 25 Gy.The blood policy in Brazil is implemented through laws and normative decrees, giving rise to a legal system that underpins the actions of hemotherapy services. In order to correct verify absorbed doses and the quality assurance process as well as the safety for the irradiator operators we describe in this paper a several of physical measurements that is mandatory to support a physicist to evaluate the quality assurance during and after the irradiation process. The results obtained from this physical measurements provided a guarantee of proper radiation dose used in hemotherapy as well as methods and procedures applied to protect the patient, employees and general public due to procedure of blood irradiation accordling the Technical Regulation of Hemotherapy Procedures of the National Health Surveillance Agency (ANVISA) and safety regulations by National Nuclear Energy Commission (CNEN).","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81204607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-05DOI: 10.15392/2319-0612.2023.2176
S. Pavão, Thadeu Das Neves Conti
The relation between human performance and nuclear safety was legitimized after nuclear accidents with important radiological consequences caused by human errors. This article presents, by a bibliographical survey, some publications of international regulation bodies of best practices in programs of human performance. In order to list the main available documents and the events occurred over the decades, the data sample range included the period between the year of 1979, with the landmark of Three Mile Island accident, until today. With the presentation of the results, this article aims to raise the discussion about the importance of a specific regulation guide regarding this subject in Brazil.
{"title":"Human performance and safety in nuclear facilities – regulatory frameworks","authors":"S. Pavão, Thadeu Das Neves Conti","doi":"10.15392/2319-0612.2023.2176","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2176","url":null,"abstract":"The relation between human performance and nuclear safety was legitimized after nuclear accidents with important radiological consequences caused by human errors. This article presents, by a bibliographical survey, some publications of international regulation bodies of best practices in programs of human performance. In order to list the main available documents and the events occurred over the decades, the data sample range included the period between the year of 1979, with the landmark of Three Mile Island accident, until today. With the presentation of the results, this article aims to raise the discussion about the importance of a specific regulation guide regarding this subject in Brazil.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91050019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-31DOI: 10.15392/2319-0612.2023.2259
R. Terini, Johnatan Dias Oliveira, E. Yoshimura
Computed tomography (CT) images contribute to high-quality medical diagnosis, but radiation dose can be quite high, requiring accurate assessment. CT dose index (CTDI) was developed for dosimetric purposes, but for scanners operated exclusively in axial mode. Nowadays, CTDI underestimate patient dose in helical CT exams. AAPM report TG111 (2010) suggested a new metric in which the patient's radiation dose is obtained from dose profiles constructed from several measurements made with a small ionization chamber. It is also possible to obtain dose profiles using properly calibrated OSL (optically stimulated luminescence) strips. The main objective of the present work is to contribute to optimizing CT dosimetry, comparing dose profiles obtained with OSL strips with measurements obtained by other authors. In this work, a “pencil” ionization chamber and 20 cm x 0.3 cm OSL strips were X-ray-irradiated, in air and in the holes of two cylindrical CT phantoms, using 100, 120, 140 kV peak voltages, both in lab and in a clinical CT scanner. Irradiated strips were read using an OSL reader built in the GDRFM. OSL profiles were calibrated against ionization chamber. From them, CTDIw and CTDIvol values were determined, differing approximately 3.9% from those of the CT scanner. From the profiles, also the planar equilibrium dose Deq,p (TG111) was evaluated in some CT protocols; Deq,p exceeded the CTDI values from the CT scanner in every case. E.g.: The percentage difference between Deq,p and CTDIvol for the head phantom ranged between 33-25%. Thus, in some cases, it could be advantageous to use calibrated OSL dosimeters instead of ionization chambers to obtain the profiles, saving time, because it is possible to obtain five OSL profiles from a single phantom irradiation.
{"title":"Application of OSL strips in CT dosimetry according to the AAPM methodology","authors":"R. Terini, Johnatan Dias Oliveira, E. Yoshimura","doi":"10.15392/2319-0612.2023.2259","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2259","url":null,"abstract":"Computed tomography (CT) images contribute to high-quality medical diagnosis, but radiation dose can be quite high, requiring accurate assessment. CT dose index (CTDI) was developed for dosimetric purposes, but for scanners operated exclusively in axial mode. Nowadays, CTDI underestimate patient dose in helical CT exams. AAPM report TG111 (2010) suggested a new metric in which the patient's radiation dose is obtained from dose profiles constructed from several measurements made with a small ionization chamber. It is also possible to obtain dose profiles using properly calibrated OSL (optically stimulated luminescence) strips. The main objective of the present work is to contribute to optimizing CT dosimetry, comparing dose profiles obtained with OSL strips with measurements obtained by other authors. In this work, a “pencil” ionization chamber and 20 cm x 0.3 cm OSL strips were X-ray-irradiated, in air and in the holes of two cylindrical CT phantoms, using 100, 120, 140 kV peak voltages, both in lab and in a clinical CT scanner. Irradiated strips were read using an OSL reader built in the GDRFM. OSL profiles were calibrated against ionization chamber. From them, CTDIw and CTDIvol values were determined, differing approximately 3.9% from those of the CT scanner. From the profiles, also the planar equilibrium dose Deq,p (TG111) was evaluated in some CT protocols; Deq,p exceeded the CTDI values from the CT scanner in every case. E.g.: The percentage difference between Deq,p and CTDIvol for the head phantom ranged between 33-25%. Thus, in some cases, it could be advantageous to use calibrated OSL dosimeters instead of ionization chambers to obtain the profiles, saving time, because it is possible to obtain five OSL profiles from a single phantom irradiation.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76979287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presented the recovery of uranium oxide and thorium oxide from aluminothermic slag from the metallurgical processing of columbite – a niobium/tantalum mineral with the presence of U3O8 and ThO2 – from a mining-industrial facility. The methodology consisted of sampling, comminution, and leaching using sulfuric acid. The head sample showed contents of (1.78 + 0.14) % for U3O8 and (3.66 + 0.04) % for ThO2. The metallurgical recovery reached values above 80% for the uranium oxide and above 70% for the thorium oxide for pH < 1.5 and process time greater than eight hours.
{"title":"Evaluation of the acid leaching technique for recovery of U3O8 and ThO2 in niobium/tantalum slag","authors":"Vanderlei Vilaça Moura, Talita Santos, Claubia Pereira","doi":"10.15392/2319-0612.2023.2165","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2165","url":null,"abstract":"This study presented the recovery of uranium oxide and thorium oxide from aluminothermic slag from the metallurgical processing of columbite – a niobium/tantalum mineral with the presence of U3O8 and ThO2 – from a mining-industrial facility. The methodology consisted of sampling, comminution, and leaching using sulfuric acid. The head sample showed contents of (1.78 + 0.14) % for U3O8 and (3.66 + 0.04) % for ThO2. The metallurgical recovery reached values above 80% for the uranium oxide and above 70% for the thorium oxide for pH < 1.5 and process time greater than eight hours.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135690610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-24DOI: 10.15392/2319-0612.2023.2162
P. Bossew, N. Suhr
Radon is a hazardous air pollutant which can cause detriment to individuals and to the society. Thus, the natural consequence is avoiding it or in practice, limiting exposure. This has led to regulation on national and international level whose objective is reduction of radon exposure. In Europe, the Basic Safety Standards (BSS) issued in 2013, whose implementation is mandatory for EU Member States, caused a boost to efforts towards radon regulation as well as to radon research since a number of components of radon abatement policy appeared not resolved sufficiently reliable in the sense of quality assurance. In this contribution, we present the state of implementation of EURATOM Basic Safety Standards in Europe and in Germany, as a particular example. We also address a number of topics currently discussed.
{"title":"European radon abatement policy: state and ongoing discussion","authors":"P. Bossew, N. Suhr","doi":"10.15392/2319-0612.2023.2162","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2162","url":null,"abstract":"Radon is a hazardous air pollutant which can cause detriment to individuals and to the society. Thus, the natural consequence is avoiding it or in practice, limiting exposure. This has led to regulation on national and international level whose objective is reduction of radon exposure. In Europe, the Basic Safety Standards (BSS) issued in 2013, whose implementation is mandatory for EU Member States, caused a boost to efforts towards radon regulation as well as to radon research since a number of components of radon abatement policy appeared not resolved sufficiently reliable in the sense of quality assurance. In this contribution, we present the state of implementation of EURATOM Basic Safety Standards in Europe and in Germany, as a particular example. We also address a number of topics currently discussed.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78229279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-24DOI: 10.15392/2319-0612.2023.2117
Eduardo Gomes Mendonça, T. Cavalcante, R. G. Vaz, E. C. F. Pereira Junior, O. Gonçalez
Radiation Sensitive MOSFETs (RADFETs) have been commonly used as ionizing radiation dosimeters. The threshold voltage variation is the main transistor parameter used for radiation dosimetry, as this voltage variation is directly related to total dose and it can be easily determined by using simple measurement and biasing circuits. In this work it is presented a novel experimental method to determine the optimal drain-source current value to be supplied to a p-type MOSFET used in a traditional RADFET configuration (diode connected transistor) for monitoring of the accumulated X- and gamma-radiation dose. Experimental results from irradiations with 60Co gamma-rays and comparison measurements with semiconductor analyzer indicate that lower supply current values result in more precise dose measurement results.
{"title":"Experimental method for determining the supply current of a PMOS power transistor for use as a RADFET dosimeter","authors":"Eduardo Gomes Mendonça, T. Cavalcante, R. G. Vaz, E. C. F. Pereira Junior, O. Gonçalez","doi":"10.15392/2319-0612.2023.2117","DOIUrl":"https://doi.org/10.15392/2319-0612.2023.2117","url":null,"abstract":"Radiation Sensitive MOSFETs (RADFETs) have been commonly used as ionizing radiation dosimeters. The threshold voltage variation is the main transistor parameter used for radiation dosimetry, as this voltage variation is directly related to total dose and it can be easily determined by using simple measurement and biasing circuits. In this work it is presented a novel experimental method to determine the optimal drain-source current value to be supplied to a p-type MOSFET used in a traditional RADFET configuration (diode connected transistor) for monitoring of the accumulated X- and gamma-radiation dose. Experimental results from irradiations with 60Co gamma-rays and comparison measurements with semiconductor analyzer indicate that lower supply current values result in more precise dose measurement results.","PeriodicalId":9203,"journal":{"name":"Brazilian Journal of Radiation Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88381154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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