TUFIC MADI FILHO
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Artigo IPEN-doc 30673 Effects of ionizing radiation on bromine doped cesium iodide scintillator crystals2024 - ALVES, J.P.S.; FILHO, T.M.; BERRETTA, J.R.; PEREIRA, M.C.C.Artigo IPEN-doc 28299 Growth of scintillating bromide-doped cesium iodide crystals for radiation detection2021 - ALVES, J.P.S.; M.FILHO, T.; PEREIRA, M.C.C.Artigo IPEN-doc 26204 Characterization of a portable thermal neutron detector2019 - COSTA, PRISCILA; RAELE, MARCUS P.; DOMIENIKAN, CLAUDIO; MADI FILHO, TUFIC; ZAHN, GUILHERME S.; GENEZINI, FREDERICO A.A portable thermal neutron detector prototype, using a PIN-type silicon photodiode coupled to a boron converter, was developed at the Nuclear and Energy Research Institute (IPEN-CNEN/SP). Several boron layers were made by Pulsed Laser Deposition method and two different prototypes were made using distinct approaches in the associated electronics. The prototypes were characterized by measurements with the cold neutron beam at PHADES (Polarized 3He and Detector Experiment Station), in the NIST Center for Neutron Research. The distance between the prototype and the neutron source was different for each prototype: 70 cm (prototype one) and 7 cm (prototype two). The linearity behavior was verified for both prototypes in order to verify the relationship between counts and neutron fluence. The intrinsic efficiency values obtained for prototypes one and two were, respectively, (1.78 ± 0.01)% and (5.2 ± 0.4)%. The angular dependence was verified only for prototype one. The concept of this detector can be applied in a future dosimeter project.Artigo IPEN-doc 26195 Growth and optics characteristics of the CsI:Li scintillator crystal for use as radiation detector2019 - TOMAZ, LUCAS F.; MADI FILHO, TUFIC; BERRETTA, JOSE R.; PEREIRA, MARIA da C.C.Materials capable of converting ionizing radiation into light photons are called scintillators, some have specific efficiencies for certain applications and types of radiation, e.g. gamma, X-ray, alpha, beta and neutrons. CsI:Tl and NaI:Tl crystals are commonly found in the market because they have several applications, but few studies have been done on lithium doped cesium iodide crystal (CsI:Li). The lithium element, in this crystal used as a dopant, is also exploited as a converter for neutron detection, as it has a shock section of 940 barns for thermal neutrons. The study of the CsI:Li crystal is convenient considering the natural abundance of the lithium element with 7.5%, besides the interest in having a low cost national scintillator material with an opportunity to search the response of a detector for different types of radiation. The CsI:Li crystal was grown with molar concentration 10-4 to 10-1, using the vertical Bridgman technique. The parameters involved in the growth process were investigated. The transmittance was evaluated in the spectral region from 190 nm to 1100 nm. Luminescence emission spectra for the CsI:Li crystal were evaluated by photometric analysis of the crystal stimulated with a 137Cs (662 keV) source in front of the coupled sample at the monochromator input. The crystals showed of maximum luminescence intensity at the wavelength of 420 nm. The response of the scintillators when excited with gamma radiation of 241Am, 133Ba, 22Na,137Cs, 60Co and neutron radiation from the AmBe source, with energy range of 1 MeV to 12 Mev was evaluated.Artigo IPEN-doc 25560 Use of the neutron activation analysis technique to determine heavy metals in Nicotiana tabacum solanaceae2018 - MADI FILHO, TUFIC; FERREIRA, ELSON B.; PEREIRA, MARIA da C.C.; BERRETTA, JOSE R.Tobacco addiction has been mentioned as a leading cause of preventable illnesses and premature disability since tobacco smoking is the main cause of lung cancer and one of the factors that most contribute to the occurrence of heart diseases, among others. The herbaceous species Nicotiana tabacum is a plant of the solanaceae family used for tobacco production. Some authors have conducted research about heavy metals and the toxicity of tobacco. It is, frequently, found in low concentrations in the ground, superficial and underground waters, even though they do not have environmental anthropogenic contributions. However, with the increase of industrial activities and mining together with the agrochemical use of contaminated organic and inorganic fertilizers, an alteration of the geochemical cycle occurs. As a consequence, the natural flow of that materials increases and release into the biosphere, where they are often accumulated in the superior layer of the ground, accessible to the roots of the plants. During planting and plant development, fertilizers and insecticides, including organochlorines and organophosphates, are used; consequently, the smoke from cigarette smoking presents various toxic substances, including heavy metals, such as Chromium (Cr), Manganese (Mn) and Antimony (Sb). Elements studied in this work. The procedures for the preparation of the samples were carried out in our laboratories and submitted to irradiation with thermal neutrons at IPEN/CNEN-SP, in the IEA-R1 research reactor. The irradiated material was, then, analyzed by gamma spectrometry, using a high purity germanium detector (HPGe).Artigo IPEN-doc 24492 Response of CsI:Pb scintillator crystal to neutron radiation2018 - PEREIRA, MARIA da C.C.; MADI FILHO, TUFIC; BERRETTA, JOSE R.; CARDENAS, JOSE P.N.; RODRIGUES, ANTONIO C.I.The helium-3 world crisis requires a development of new methods of neutron detection to replace commonly used 3He proportional counters. In the past decades, great effort was made to developed efficient and fast scintillators to detect radiation. The inorganic scintillator may be an alternative. Inorganic scintillators with much higher density should be selected for optimal neutron detection efficiency taking into consideration the relevant reactions leading to light emission. These detectors should, then, be carefully characterized both experimentally and by means of advanced simulation code. Ideally, the detector should have the capability to separate neutron and gamma induced events either by amplitude or through pulse shape differences. As neutron sources also generate gamma radiation, which can interfere with the measurement, it is necessary that the detector be able to discriminate the presence of such radiation. Considerable progress has been achieved to develop new inorganic scintillators, in particular increasing the light output and decreasing the decay time by optimized doping. Crystals may be found to suit neutron detection. In this report, we will present the results of the study of lead doped cesium iodide crystals (CsI:Pb) grown in our laboratory, using the vertical Bridgman technique. The concentration of the lead doping element (Pb) was studied in the range 5x10-4 M to 10-2 M . The crystals grown were subjected to annealing (heat treatment). In this procedure, vacuum of 10-6 mbar and continuous temperature of 350°C, for 24 hours, were employed. In response to neutron radiation, an AmBe source with energy range of 1 MeV to 12 MeV was used. The activity of the AmBe source was 1Ci Am. The fluency was 2.6 x 106 neutrons/second. The operating voltage of the photomultiplier tube was 1700 V; the accumulation time in the counting process was 600 s and 1800 s. The scintillator crystals used were cut with dimensions of 20 mm diameter and 10 mm height.Artigo IPEN-doc 24188 Study and project of the new rack with boron for storage of fuel elements burned in the IEA-R1 research reactor2017 - RODRIGUES, ANTONIO C.I.; MADI FILHO, TUFIC; SILVA, DAVILSON G. daThe IEA-R1 research reactor works 40h weekly with 4.5 Mw power. The storage rack for spent fuel elements has less than half of its initial capacity. Under these conditions (current conditions of reactor operation 32h weekly will have 3 spend fuel by year, then, approximately 3 utilization rate Positions/year). Thus, we will have only about six years of capacity for storage. Whereas the desired service life of the IEA-R1 is at least another 20 years, it will be necessary to increase the storage capacity of spent fuel. Hence, it is necessary to double the wet storage capacity (storage in the IEA-R1 reactor's pool). After reviewing the literature about materials available for use in the construction of the new storage rack with absorber of neutrons, the BoralcanTM (manufactured by 3TMhis) wwaosr kc hporseesne,n dtsu es ttuod iitess :p r(oap) efrotrie tsh. e construction of new storages racks with double of the current capacity using the same place of current storages racks and (b) criticality analysis using the MCNP-5 code. Two American Nuclear Data Library were used: ENDF / B-VI and ENDF / B-VII, and the results obtained for each data bases were compared. These analyzes confirm the possibility of doubling the storage capacity of fuel elements burned in the same place occupied by the current storage rack attending to the IEA-R1 reactor needs and attending the safety requirements according to the National Nuclear Energy Commission - CNEN and the International Atomic Energy Agency (IAEA). To calculate the keff were considered new fuel elements (maximum possible reactivity) used in full charge of the storage rack. With the results obtained in the simulation we can conclude that doubling the amount of racks for spent fuel elements are complied with safety limits established in the IAEA standards and CNEN of criticality (keff < 0.95).Artigo IPEN-doc 24134 Characteristics of Pb2+ doped CsI matriz under gamma and neutron excitations2017 - PEREIRA, MARIA da C.C.; MADI FILHO, TUFIC; BERRETTA, JOSE R.; TOMAZ, LUCAS F.; PINTO, MARLENE C.In recent years, there has been an increasing interest in finding new fast scintillating material or improve the characteristics of known scintillators for the demand of high energy physics, industrial and nuclear medical applications. Ions divalent lead Pb2+ built in some crystal structures are efficient emission centers and their applications in scintillators was and still is the reason of an intensive study of emission properties of different compounds containing these ions. The aggregation of impurities in CsI is poorly studied. The problem of impurity aggregation in CsI is of interest from point of view of the luminescent properties modification of this scintillation material. In this context, the crystals of Pb2+ doped CsI matrix were grown by the vertical Bridgman technique and subjected to annealing in vacuum of 10-6 mbar and continuous temperatura of 350°C, for 24 hours, and then they were employed. To evaluate the response of the CsI:Pb scintillator crystal to gamma radiation, radioactive sources of 137Cs (662 keV), 60Co (1173 keV and 1333 keV), 22Na (511 keV and 1275 keV) and 133Ba (355 keV) was used. The operating voltage of the photomultiplier was 2700 V for the detection of gamma rays and the accumulation time in the counting process was 600 s. The crystals used in gamma spectroscopy were cut with dimensions of 20 mm in diameter and 20 mm in height. The scintillator response to neutron radiation from a radioactive source of Am/Be with energy range of 1 MeV to 12 MeV was available. The activity of the AmBe source was 1Ci Am. The fluency was 2.6 x 106 neutrons / second. The operating voltage of the photomultiplier tube was 1300 V. The accumulation time in the counting process was 600 s. The scintillator crystals were cut with dimensions of 20 mm diameter and 10 mm height. With the results obtained, it may be observed that the crystals are sensitive to these radiations.Artigo IPEN-doc 23868 Experimental and MCNP studies of paraffin and polyethylene in neutron moderation and BF3 detector efficiency2013 - CARDENAS, JOSE P.N.; MADI FILHO, TUFIC; PETRI, ANNA R.; SANTOS, ROBINSON A. dos; MARTINS, JOAO F.T.; CARVALHO, DIEGO V.S.; ALVARENGA, T.; BELLEZZO, M.; LARANJO, G.; LIMA, M.; OLIVEIRA, P.; PEREIRA, MARIA da C.C.The Nuclear and Energy Research Institute – IPEN, offers post-graduate programs, namely: Nuclear Technology - Applications (TNA), Nuclear Technology - Materials (TNM), Nuclear Technology - Reactors (TNR). The Institute programs mission is to form expert technicians and engineers with a strong knowledge in their discipline to work in the nuclear area. The course: “Theoretical Fundaments and Practices of the Instrumentation used in Nuclear Data Acquisition” covers the use of laboratory nuclear instrumentation and the accomplishment of experiments to obtain nuclear parameters. One of these experiments is object of this work: “Experimental and MCNP Studies of Paraffin and Polyethylene Neutron Moderation and BF3 Detector Efficiency”. Neutrons are uncharged particles and, therefore, cannot be detected by Coulomb interactions. Thus, the detector assembly used must contain some kind of material with high cross section for interaction with neutrons, called converters. A boron trifluoride (BF3) detector was used in this experiment to detect neutron in real time. However, the response of this arrangement varies according to the energy range of incident neutrons. Their efficiency for thermal neutrons is above 90%, but, this result decreases, significantly, for neutrons of energy greater than 0.5 eV. The neutron moderation and, consequently, its energy variation were obtained by interposing different thicknesses of moderator material (Paraffin or Polyethylene) between the source and the detector.Artigo IPEN-doc 23876 Methodological proposal for identification and evaluation of environmental aspects and impacts of IPEN nuclear facilities: a case study applied to the nuclear fuel center2013 - MATTOS, LUIS A.T. de; MADI FILHO, TUFIC; MELDONIAN, NELSON L.This work presents an application of Failure Mode Effect Analysis (FMEA) to the process of identification of environmental aspects and impacts as a part of implementation and maintenance of an Environmental Management System (EMS) in accordance with the ISO 14001 standard. Also, it can contribute, as a complement, to the evaluation and improvement of safety of the installation focused. The study was applied to the Nuclear Fuel Center (CCN) of Nuclear and Energy Research Institute (IPEN) , situated at the Campus of University of Sao Paulo, Brazil. The CCN facility has the objective of promoting scientific research and of producing nuclear fuel elements for the IEA-R1 Research Reactor. To identify the environmental aspects of the facility activities, products, and services, a systematic data collection was carried out by means of personal interviews, documents, reports and operation data records consulting. Furthermore, the processes and their interactions, failure modes, besides their causes and effects to the environment, were identified. As a result of a careful evaluation of these causes it was possible to identify and to classify the major potential environmental impacts, in order to set up and put in practice an Environmental Control Plan for the installation under study. The results have demonstrated the validity of the FMEA application to nuclear facility processes, identifying environmental aspects and impacts, whose controls are critical to achieve compliance with the environmental requirements of the Integrated Management System of IPEN. It was demonstrated that the methodology used in this work is a powerful management tool for resolving issues related to the conformity with applicable regulatory and legal requirements of the Brazilian Nuclear Energy Commission (CNEN) and the Brazilian Institute of Environment (IBAMA).