MARIA DA CONCEICAO COSTA PEREIRA

MARIA DA CONCEICAO COSTA PEREIRA

(Fonte: Lattes)

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Possui graduação em Química Industrial pela Escola Superior de Química Oswaldo Cruz (1984), Mestrado pelo Instituto de Pesquisas Energéticas e Nucleares - USP (1997) e Doutorado pelo Instituto de Pesquisas Energéticas e Nucleares - USP (2006). Atualmente é pesquisadora do Instituto de Pesquisas Energéticas e Nucleares. Possui experiência na área de Química e Engenharia Nuclear, atuando principalmente nos seguintes temas: detectores de radiação, tempo de decaimento de luminescência, cintilação e crescimento de cristais cintiladores inorgânicos. Orientadora de Mestrado (Texto extraído do Currículo Lattes em 16 nov. 2021)

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The growth and scintillation characteristics of lithium doped CsI crystals
2011 - PEREIRA, MARIA da C.C.; CARDENAS, JOSE P.N.; MADI FILHO, TUFIC
Inorganic scintillators play an important role in the detection and spectroscopy of gamma and X-rays, as well as in neutrons and charged particles. For a variety of applications, new inorganic scintillation materials are being studied. New scintillation detector applications arise continuously and the interest in the introduction of new fast scintillators becomes relevant. Scintillation crystals based on cesium iodide (CsI) have relatively low hygroscope, easy handling and low cost, features that favor their use as radiation detectors. In this work, lithium doped CsI crystals were grown using the vertical Bridgman technique. In this technique, the charge is maintained at high temperature for 10 h to for the material melting and complete reaction. The temperature gradient 21° C/cm and 1 mm/h descending velocity are chosen as technique parameters. After growth is finished, the furnace is cooled at a rate of 20° C/h to room temperature. The concentration of the lithium doping element (Li) studied was 10-3 M. Analyses were carried out to evaluate the scintillator developed concerning two responses: a) to the gamma radiation, in the energy range of 350 keV to 1330 keV and b) to neutron from AmBe source, with energy range of 1MeV to 12 MeV. T.S. Korolevaa et al [1] describe in their paper about new scintillation materials, for registration of gamma-rays, X-rays, neutrons and neutrinos. One of these materials is 6Li. Lithium can capture neutrons without gamma-ray emission and, thus, reducing the back-ground. The neutron detection reaction is 6Li(n,a)3H with a thermal neutron cross section that 940 barns. In this paper we investigated the feasibility of the CsI:Li crystal as a gamma ray and neutron detector which can be used for monitoring, due to the fact that in our work environment we have two nuclear research reactors, calibration systems and radioisotope production.
The use of the neutron activation analysis technique to determine heavy metals in Nicotiana tabacum solanaceae
2018 - 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 and 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 researched about heavy metals and the toxicity of tobacco. Heavy metals are frequently found in low concentrations in ground, superficial and underground waters, even though it does not have environmental anthropogenic contributions. However, with the increase of the industrial activities and mining and the agrochemical use of contaminated organic and inorganic fertilizers, an alteration of the geochemical cycle occurs. As a consequence, the natural flow of heavy metals increases the release of these elements into the biosphere, where they are frequently accumulated in the superior layer of the ground, accessible to the roots of the plants. Traces of available heavy metals may be found in surface and subsurface aquatic systems and soils, even when there is no anthropogenic influence on the environment, and they frequently accumulate in the upper layer of the soil, where they are accessible to the roots of the plants. Except for the exclusion species, most plant species that grow on soil contaminated by heavy metals cannot avoid the absorption of these elements, but only limit their translocation. During planting and plant development, fertilizers and insecticides, including organochlorines and organophosphates, are used and the smoke from cigarette smoking presents various toxic substances, including heavy metals such as Chromium (Cr) and Manganese (Mn). The samples preparation procedures were carried out in our laboratories and submitted to the irradiation with thermal neutrons in the IPEN/CNEN-SP, in the IEA-R1 research reactor. The irradiated material was analyzed by gamma spectrometry using a high purity germanium detector (HPGe).
Optical properties and radiation response of Li ion-doped CsI scintillator crystal
2019 - PEREIRA, MARIA da C.C.; MADI FILHO, TUFIC; BERRETTA, JOSE R.; TOMAZ, LUCAS F.; MADI, MIRIAM N.
Scintillators are materials that convert the energy of ionizing radiation into a flash of light. Due to the existence of different types of scintillators, they are classified into three groups according to their physicochemical characteristics, namely, inorganic, organic and gaseous scintillators. Among the inorganic crystals, the most frequently used as scintillator consist of alkali metals, in particular alkaline iodides. Scintillation materials have many applications, for instance in medical imaging, security, physics, biology, non-destructive inspection and medicine. In this study, lithium doped CsI scintillator crystals were grown using the vertical Bridgman technique. The concentration of the lithium doping element (Li) studied was 10-4 M to 10-1 M. Analyses were carried out to evaluate the developed scintillators with regard to luminescence emission and optical transmittance. The luminescence emission spectra of these crystals were measured with a monochromator for gamma radiation from 137Cs source excitation. The determination of the dopant distribution along the crystalline axis allowed the identification of the region with Li concentration uniformity, which is the region of the crystalline volume indicated for use as a radiation detector. The crystals were excited with neutron radiation from AmBe source, with the energy range of 1 MeV to 12 MeV. 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. Accordingly, experiments were performed using gamma radiation in the energy range of 59 keV to 1333 keV in order to verify the ability of the detector to discriminate the presence of different types of radiation.
Study and development of neutron detectors using doped CsI crystals
2019 - MADI FILHO, TUFIC; PEREIRA, MARIA da C.C.; BERRETTA, JOSE R.; TOMAZ, LUCAS F.; MADI, MIRIAM N.
The development of new radiation detectors using scintillation crystals, which increase response speed, dose and energy accuracy and, at the same time, the feasibility of simplifying and reducing costs in the production process are always necessary. In the CTR-IPEN laboratory, pure and doped CsI crystals were grown using the Bridgman technique. This work shows the obtained results using a doped CsI scintillator with the converters: Br, Pb, Tl, Li as alpha, beta, gamma and neutron detectors.
Optical properties and radiation response of Li ion-doped CsI scintillator crystal
2019 - PEREIRA, MARIA da C.C.; MADI FILHO, TUFIC; BERRETTA, JOSE R.; TOMAZ, LUCAS F.; MADI, MIRIAM N.
Scintillators are materials that convert the energy of ionizing radiation into a flash of light. Due to the existence of different types of scintillators themselves, they were classified into three groups according to their physicochemical characteristics, namely, inorganic, organic and gaseous scintillators. Among the inorganic crystals, the most used as scintillator are constituted of alkali metals, in particular alkaline iodides. Scintillation materials are used in many applications, such as medical imaging, security, physics, biology, non-destructive inspection and medicine. In this work, lithium doped CsI scintillator crystals were grown using the vertical Bridgman technique. The concentration of the lithium doping element (Li) studied was 10-4 M to 10-1 M. Analyses were carried out to evaluate the scintillators developed concerning to luminescence emission and optical transmittance. The luminescence emission spectra of these crystals were measured with a monochromator for gamma radiation from 137Cs source excitation. The optical transmittance measurements were made in the CsI;Li crystal, in a spectral region of 200 nm to 1100 nm. Determination of the dopant distribution along the crystalline axis, allowing to identify the region with Li concentration uniformity, which is the region of the crystalline volume indicated for use as radiation detector. The crystals were excited with neutron radiation from AmBe source, with energy range of 1 MeV to 12 MeV. As with neutron sources also generate gamma radiation, which can interfere with the measurement, it is necessary that detector be able to discriminate the presence of such radiation. Accordingly, experiments were performed using gamma radiation in the energy range 59 keV to 1333 keV in order to verify the ability of the detector to discriminate the presence of different types of radiation.
Study and development of neutron detectors using doped CsI crystals
2019 - MADI FILHO, TUFIC; PEREIRA, MARIA da C.C.; BERRETTA, JOSE R.; TOMAZ, LUCAS F.; MADI, MIRIAM N.
In the development of nuclear radiation detectors one must take into consideration the process of interaction of the radiation under study with matter. In the case of neutron detectors it must be considered that the detection of neutrons is not trivial in view of the lack of charges of these particles and the peculiarity of their interactions with matter. Another difficulty in the detection of neutrons consists in the discrimination of the electronic impulses generated by the neutrons of those generated by other radiations, almost always present. The main propositions of neutron-sensitive detectors consist of gaseous detectors, scintillators and semiconductors. These detectors intrinsically are not sensitive to neutrons, so they need a radiation converter based on nuclear reactions of the type: Neutron + Converter -> Detectable radiation. Some reactions with neutrons are more used, such as: 10B (n, α), 6Li (n, α) and 3He (n, p). Neutron-scintillation crystal are being the object of active research in several research centers and having their implementations in several applications. The development of new radiation detectors using scintillation crystals, which increases response speed, dose and energy accuracy and, at the same time, the feasibility of simplifying and reducing costs in the production process is always necessary. In the CTR-IPEN laboratory, pure and doped CsI crystals were grown using the Bridgman technique. This work shows the obtained results using doped CsI scintillator with the converters: Br, Pb, Tl, Li as neutron detectors.
Development and characterization of CsI (Tl) crystal for use as a radiation detector
2019 - SUZART, KAROLINE F.; HAMADA, MARGARIDA M.; PEREIRA, MARIA da C.C.; MESQUITA, CARLOS H. de
Cesium iodide crystal activated with thallium (CsI(Tl)) is used as radiation sensor because of its favorable characteristics as scintillator when excited by gamma radiation. This crystal has good mechanical strength and it is not hygroscopic. In the present work the CsI(Tl) crystal was growed in the Nuclear Energy Research Institute (IPEN/CNEN/SP) by Brigdman technique in different sizes. The scintillator response was studied through gamma radiation from 99mTc source with the energy of 140 keV. The crystals were coupled to a photomultiplier tube using 0.5 McStokes viscosity silicone grease as the optical interface. All electronics for signal measurements were developed at IPEN. Measurements of luminescence and gamma spectrometry of a 99mTc source were performed. The energy resolution of the crystals was determined by the spectrum photopeak considering its full width at half maximum (FWHM).
Growth and optics characteristics of the CsI:Li scintillator crystal for use as radiation detector
2019 - 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.
Toxicity and color reduction of reactive dyestuff RB21 and surfactant submitted to electron beam irradiation
2019 - MELO, CAMILA G.; ROSA, JORGE M.; GARCIA, VANESSA S.G.; BORRELY, SUELI I.; PEREIRA, MARIA da C.C.
There is an unwelcome reaction between the coloring and the water during the dyeing procedure, a portion of the coloring agent is lost in the bathing and it will compose the final whole effluent. The high absorbance index is related to lost dyes and they also contribute with the toxic effects to the aquatic biota. In addition, these effluents contain large quantity of surfactants applied during dyeing baths, which also contribute to the high toxicity in these samples. The objective of this study was to evaluate electron beam irradiation technology, applied in samples of the Color Index Reactive Blue 21 (RB21) dye and in samples of surfactant nonionic and in order to reduce toxicity for both and for RB21, color reduction. Among the objectives of the study there are the dye exhaustion degree, and some physic-chemical parameters. The acute toxicity assays were carried with Daphnia similis microcrustacean and the results for of dyestuff solution were: the irradiated samples with concentration of 0.61g.L-1 did not present significant results, the EC 50(%) value was to 58.26 for irradiated sample with 2.5kGy and EC 50(%) 63.59 for sample irradiated with 5kGy. The surfactant was more toxic than RB 21, with EC 50(%) value at 0.42. The color reduction reached 63.30% for the sample of the lowest concentration of effluent. There was a reduction of pH during irradiation.
Estudo sobre toxicidade do efluente e do consumo hídrico e energético no tingimento de poliamida
2018 - GARCIA, VANESSA S.G.; PEREIRA, MARIA C.; ROSA, JORGE M.; BORRELY, SUELI I.
O estudo concentrou-se na determinação do consumo hídrico e energético durante o tingimento da poliamida, bem como na avaliação do efeito tóxico do efluente para o microcurstáceo Daphnia similis. O processo de tingimento necessário para o tingimento de um quilograma de substrato consome energia suficiente para um banho de nove horas de duração utilizando-se um chuveiro convencional (4000 W). O efluente pode ser considerado como muito tóxico tendo em vista que a CE50 foi 0,61 ± 0,21 (%, v/v) após 48 horas de exposição. Conforme orientação da Resolução CONAMA 430/2011 o efluente deve ser tratado em nível tal que não induza toxicidade quando lançado no corpo receptor. Busca por tecnologias que permitam redução de toxicidade, reuso de efluentes e otimização de processos de tingimento, são de extrema necessidade dentro desta atividade industrial.