JOSEMARY ANGELICA CORREA GONCALVES

JOSEMARY ANGELICA CORREA GONCALVES

(Fonte: Lattes)

Resumo

Possui graduação em Física pela Pontifícia Universidade Católica de São Paulo (1987), mestrado em Técnicas e Aplicações Nucleares pelo Instituto de Pesquisas Energéticas e Nucleares (1990), doutorado em Técnicas e Aplicações Nucleares pelo Instituto de Pesquisas Energéticas e Nucleares (1993) e Pós-Doutorado de Curta duração na Universidade de Coimbra com bolsa FAPESP (1997). Foi professora da Pontifícia Universidade Católica de São Paulo entre 1996-2020. Atualmente é pesquisadora titular do Instituto de Pesquisas Energéticas e Nucleares. Tem experiência na área de Engenharia Nuclear, com ênfase em Instrumentação para Medida e Controle de Radiação, atuando principalmente nos seguintes temas: detectores semicondutores de Si, espectrometria e dosimetria de partículas carregadas e radiação eletromagnética, detectores gasosos de catodo resistivo e parâmetros de transporte de elétrons em gases. (Texto extraído do Currículo Lattes em 12 nov. 2021)

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Measurement of the insensitive surface layer thickness of a PIN photodiode based on alpha-particle spectrometry
2021 - PASCOALINO, K.; GONCALVES, J.A.C.; CAMARGO, F.; BUENO, C.C.
Count rate effect on the response of a low-cost PIN diode for electron spectrometry
2019 - PETRI, ANNA R.; BARROS, SUELEN F.; GONCALVES, JOSEMARY A.C.; BUENO, CARMEN C.; MAIDANA, NORA; MARTINS, MARCOS N.; VANIN, VITO R.
The response of a low-cost Si photodiode model BPX 65 for low-energy electron spectrometry is investigated envisaging its use in measurements of electron multiple elastic scattering. The electron beam with energy between 10-100 keV is delivered by the gun of the Racetrack Microtron at Instituto de Física, Universidade de São Paulo, with an energy dispersion less than 0.5 keV. The energy resolution achieved was less than 3.5 keV, limited mainly by noise from the electronic acquisition chain. For count rates between 20 and 5500 counts/s, the variation on the centroid of electron peak was smaller than 0.4% throughout the energy range. Therefore, the BPX 65 is suitable for electron spectrometry.
Comparative evaluation of the performance of thin diodes used as on-line dosimeters in radiation processing applications
2019 - GONCALVES, JOSEMARY A.C.; MANGIAROTTI, ALESSIO; BUENO, CARMEN C.
In this work, we report a comparison between the performance of two samples of commercial PIN photodiodes (SFH206K from OsramÒ and S2506-04 from HamamatsuÒ) mainly addressing the variation of their current sensitivities with accumulated dose ranging from 0-15 kGy. All the results so far obtained have revealed that the radiation induced currents are linearly dependent on dose rates from 3.65 to 55.64 Gy/h. The current sensitivity of both unirradiated diodes (0.178 nA.h/Gy.mm3) slightly decreases with accumulated dose, namely 0.32%/kGy (SFH206K) and 1.4%/kGy (S2506-04). Although the SFH206K device compares favorably with the S2506-04, both diodes can be considered as a low budge alternative, good enough for on-line dosimetry applications in the field of radiation processing.
A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing
2017 - CAMARGO, FABIO de; GONÇALVES, JOSEMARY A.C.; BUENO, CARMEN C.
In this work, we report on the results obtained with rad-hard Standard Float Zone (STFZ) and Diffused Oxygenated Float Zone (DOFZ) silicon diodes in radiation processing dosimetry. The dosimetric probes were designed to operate in the direct current mode, as on-line radiation dosimeter. The irradiation of the samples was performed using a 60Co source with a dose rate of almost 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. In this dose range it is observed a significant decrease in the photocurrent generated in both devices due to gamma radiation defects produced in their active volumes. To mitigate this effect, the samples were pre-irradiated with 60Co gamma rays at 700 kGy. Despite of being less sensitive, these devices presented stable and reproducible current signals with a relative sensitivity decrease of about 19% within the whole range of dose studied. The dose-response curves of the pre-irradiated diodes showed quadratic behavior with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison of the FZ and DOFZ responses evidenced that the latter was slightly superior to the first. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications.
Effect of the ohmic drop in a RPC-like chamber for measurements of electron transport parameters
2017 - PETRI, ANNA R.; MANGIAROTTI, ALESSIO; GONÇALVES, JOSEMARY A.C.; BUENO, CARMEN C.
The main advantage of Resistive Plate Chambers (RPCs), applied, for instance, in High-Energy Experiments and Positron Emission Tomography (PET), is that it is spark-protected due to the presence of, at least, one highresistive electrode. However, the ohmic drop across the latter can affect the charge multiplication significantly. In this work, we investigate this effect in a RPC-like chamber. The counter was filled with nitrogen at atmospheric pressure and the primary ionization was produced by the incidence of nitrogen pulsed laser beam on an aluminum cathode. The illumination area of the cathode was measured using a foil of millimetric paper overlaid on this electrode. In this way, the resistance of the glass anode could be estimated using the known resistivity of the glass (ρ=2×1012 Ω.cm). Therefore, the voltage drop across the dielectric was calculated by the product of the current across the gas gap and the anode resistance. In order to mitigate the effect of the resistive electrode, the laser beam intensity was limited by interposing metallic meshes between the laser and the chamber window. The dependence of the ohmic drop from the applied voltage was analyzed. The results obtained shown that, without the meshes, the ohmic drop corresponds up to 7% of the applied voltage, preventing the detection system to reach values of density-normalized electric fields in the gas gap (Eeff/N) higher than 166 Td. By minimizing the laser beam intensity and, consequently, the primary ionization, the ohmic drop represented only 0.2% of the applied voltage, extending the Eeff /N range up to 175 Td.
Diagnostic X-ray dosimeters using standard float zone (FZ) and XRA-50 commercial diodes
2017 - GONÇALVES, JOSEMARY A.C.; BARROS, VINICIUS S.M.; ASFORA, VIVIANE K.; KHOURY, HELEN J.; BUENO, CARMEN C.
The results obtained with a standard float zone (FZ) silicon diode, processed at the Helsinki Institute of Physics, used as on-line diagnostic X-ray dosimeter are described in this work. The device was connected in the shortcircuit current mode to the input of an integrating electrometer. The response repeatability and the current sensitivity coefficient of the diode were measured with diagnostic X-ray beams in the range of 40-80 kV. The dose-response of the device, evaluated from 10 mGy up to 500 mGy, was linear with high charge sensitivity. Nevertheless, significant energy dependence was observed in the charge sensitivity of FZ device for energies below 70 kV. The dosimetric characteristics of this FZ diode were compared to those of an XRA-50 commercial Si diode, specially designed to X-ray dosimetry. The results obtained with the FZ diode evidenced that it can be an alternative choice for diagnostic X-ray dosimetry, although it needs to be calibrated for individual X-ray beam energies. The studies of long-term stability and the radiation hardness of these diodes are under way.
Feasibility studies of using thin entrance window photodiodes for clinical electron beam dosimetry
2017 - NASCIMENTO, CRISTINA R.; ASFORA, VIVIANE K.; BARROS, VINICIUS S.M.; GONÇALVES, JOSEMARY A.C.; ANDRADE, LUCAS F.R.; KHOURY, HELEN J.; BUENO, CARMEN C.
The response of the commercial XRA-24 PIN photodiode (5.76 mm2 active area) for clinical electron beam dosimetry covering the range of 8-12 MeV was investigated. Within this energy range, the charge generated in the diode’s sensitive volume is linearly dependent on the absorbed dose up to 320 cGy. However, charge sensitivity coefficients evidenced that the dose response of the diode is slightly dependent on the electron beam energy. Indeed, the diode’s energy dependence was within 8.5% for 8-12MeV electron beams. On the other hand, it was also observed an excellent repeatability of these results with a variation coefficient (VC) lower than 0.4%, which is within the 1% tolerance limit recommended by the AAPM TG-62. Furthermore, the agreement between the percentage depth dose profiles (PDD) gathered with the diode and the ionization chamber allowed achieving the electron beam quality within 1% of that obtained with the ionization chamber. Based on these results, the photodiode XRA-24 can be a reliable and inexpensive alternative for electron beams dosimetry.
Dosimetry of an animal irradiation system
2015 - ALVES, NELSON M.; FUNARI, ANA P.; MIRANDA, JURANDIR T.; NAPOLITANO, CELIA M.; GONCALVES, JOSEMARY A.C.; BUENO, CARMEN C.
A dosimetric survey of the DC1500/25/04 electron beam plant installed at IPEN-CNEN/SP
2015 - KUNTZ, FLORENT; SOMESSARI, ELIZABETH S.R.; SILVEIRA, CARLOS G. da; BUENO, CARMEN C.; CALVO, WILSON A.P.; NAPOLITANO, CELIA M.; GONCALVES, JOSEMARY A.C.; SOMESSARI, SAMIR L.
A modified setup for measuring the first ionization coeficient of tissue equivalent gases at low pressure
2015 - PETRI, ANNA R.; GONCALVES, JOSEMARY A.C.; MANGIAROTTI, ALESSIO; BUENO, CARMEN C.