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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Online electron beam monitoring with a diode-based dosimetry system in routine quality control
2023 - GONCALVES, JOSEMARY A.C.; MANGIAROTTI, ALESSIO; SOMESSARI, ELIZABETH S.R.; NAPOLITANO, CELIA M.; BUENO, CARMEN C.
Dosimetric parameters and radiation tolerance of epitaxial diodes for diagnostic radiology and computed tomography X-rays
2023 - GONCALVES, JOSEMARY A.C.; MANGIAROTTI, ALESSIO; POTIENS, MARIA P.A.; CALDAS, LINDA V.E.; BUENO, CARMEN C.
Characterization of a commercial PIN diode for radiotherapy photon beam dosimetry
2023 - SILVA, IANDRA T.; PIERI, KAREN; ALBINO, LUCAS D.; FONTANA, THIAGO S.; SANTOS, MATHEUS F. dos; ROESLER, ERNESTO; ASFORA, VIVIANE K.; OLIVEIRA, CHARLES; GONCALVES, JOSEMARY A.C.; BUENO, CARMEN C.; KHOURY, HELEN J.
Dosimetric evaluation of an epitaxial silicon diode as an online dosimeter for orthovoltage photon beam radiotherapy
2021 - BUENO, C.C.; GONCALVES, J.A.C.; MANGIAROTTI, A.
The response of a dosimetry system based on an epitaxial silicon diode as an online dosimeter for orthovoltage photon beam radiotherapy has been investigated in this work. To be used as a dosimeter, each diode is housed in a light-tight probe, and its readout electrode is directly connected to the Keithley 6517B electrometer. All current measurements are carried out in short-circuit mode with the diode unbiased and its backplane grounded. The data acquired by the electrometer are directly sent to a personal computer via a GBIP interface controlled by software developed in LabView to analyze the current signals. A Pantak/Seifert X-ray tube is used to irradiate the diode, placed 50.0 cm away in a radiation field of 8 cm, with 10, 25, 30, and 50 kV photons. The dose rate response is investigated for the 50 kV beam by varying the current tube from 2 to 20 mA. As expected, the induced current is linearly dependent on the dose rate within the range of 0.8 and 8.05 mGy/s. The current signals are quite stable, with a repeatability parameter of less than 0.2%. The dose-responses assessed offline by integrating the current signals are linear between 0.5 and 3.0 Gy despite being slightly dependent on the photon energy. However, in this dose range, no dose rate dependence is observed. These results are theoretically supported by dose and dose rate calculations performed assuming the diode is thin compared with the standard values of the minority carrier diffusion lengths in the epitaxial layer. Good agreement is found between calculations and experimental data. Investigations of possible radiation damage produced in the diode through dynamic measurements of dark current and capacitance as a function of the accumulated dose are currently in progress.
Dose rate mapping in an industrial 60Co irradiator using an online photodiode-based dosimetry system
2021 - GONCALVES, J.A.C.; MANGIAROTTI, A.; BUENO, C.C.
In the radiation processing field, any irradiation process is designed to irradiate products uniformly, but in practice, a reasonable variation in the absorbed dose through the product is accepted. However, the irradiation of inhomogeneous or irregularly shaped products gives rise to complex dose variations only assessed through dose mapping. It requires complementary dosimeters bearing good spatial resolution, prompt and easy readout, and cost-effectiveness. These features are found in silicon diodes that, despite all these advantages, are prone to radiation damage. This damage is mitigated with photodiodes whose thicknesses are much smaller than the minority carrier diffusion length at the anticipated accumulated dose. In this work, an in-house dosimetry system based on a thin photodiode is applied for online mapping dose rates, between 3.7 and 52.8 Gy/h, delivered by a Panoramic 60Co industrial facility. The operational principle of these dosimeters relies on the real-time acquisition of the induced currents from the irradiated diode operating in the short-circuit mode without externally applied voltage. Under this condition, the dose is assessed offline via the integration of these current signals. The radial mapping of the radiation field is performed by rotating the diode around the central axis of the panoramic irradiator, covering 360º at intervals of 10º. For comparative purposes, alanine dosimeters are also irradiated together with the diode. The experimental results are benchmarked with Monte Carlo simulations of the dose rate curves. Good agreement between the simulated values and the readings of both dosimeters is found. It reveals that the photodiode-dosimetry system is a reliable alternative to map dose rate fields and the effectiveness of Monte Carlo simulations as a predictive tool for dose rate measurements in an irradiator.
Transit dose measurements using alanine and diode-based dosimeters
2021 - GONCALVES, J.A.C.; SOMESSARI, E.S.R.; NAPOLITANO, C.M.; SOMESSARI, S.L.; BUENO, C.C.
Evaluation of a diffused oxygenated float zone (DOFZ) diode response as a high-dose dosimeter
2021 - CAMARGO, F.; PASCOALINO, K.; GONCALVES, J.A.C.; BUENO, C.C.
Dosimetric characterization of thin diodes in an electron beam facility for radiation processing
2019 - GONCALVES, J.A.C.; MANGIAROTTI, A.; ASFORA, V.K.; KHOURY, H.J.; BUENO, C.C.
Introduction: Silicon diodes have been employed as relative dosimeters in clinical photon and electron beams. However, they are prone to radiation damage that produces a drop of their current sensitivities with increasing accumulated doses. This effect is attributed to the decrease of the minority carrier diffusion lengths which diminishes the sensitive volume of the diode. Theoretically, it is possible to mitigate the decay of the current sensitivity by choosing diodes with thicknesses smaller than the lowest minority carrier diffusion lengths anticipated for the foreseen accumulated dose. This surmise has been followed up in this work by evaluating the response of thin diodes (SFH00206K) for the dosimetry of electron beams used in radiation processing. Methods: The diode with 10 μm of depletion layer at 0V was produced on n type Si wafers of 220 m thickness. As a dosimeter, the device was housed in a probe and connected to an electrometer to be operated in short-circuit current mode without bias voltage. To carry out the irradiation, the probe was placed on a conveyor belt that crosses the radiation fi eld of a 1.5 MeV electron beam. Results: The currents were registered as a function of the exposure time for dose-rates within 2-8 kGy/s and accumulated doses up to 350 kGy. The dosimeter was characterized with respect to the linearity between current and dose-rate, repeatability and reproducibility of the current signals. Its lifespan was investigated, particularly addressing the stability of the current sensitivity factor with increasing absorbed doses. The measurements were benchmarked against calculations of the current taking into account the fraction of the electron energy deposited in the active volume of the diode, the dose-rate, and the values of diffusion lengths. Conclusion: All experimental data so far obtained prove that this diode can be used in electron beam dosimetry. Furthermore, a fair agreement was found between theoretical and experimental results.
Study of the response of a commercial photodiode for photons and electrons with energies between 10 and 100 keV
2019 - PETRI, ANNA R.; MALAFRONTE, ALEXANDRE A.; GONCALVES, JOSEMARY A.C.; BARROS, SUELEN F.; BUENO, CARMEN C.; MAIDANA, NORA L.; MANGIAROTTI, ALESSIO; MARTINS, MARCOS N.; VANIN, VITO R.
In this work, a commercial low-cost silicon PIN (p type-Intrinsic-n type) photodiode model BPX 65 is characterized with respect to reverse current and capacitance of the junction. The measurements indicate that the photodiode is fully depleted for a reverse bias greater than 17 V and the width of the depletion zone is estimated to be 60 (3) μm. The device has been applied for gamma spectrometry, showing a resolution around 2.4 keV (FWHM - Full Width at Half Maximum) for photons with energies between 14 and 136 keV. This is the same resolution obtained with a pulser, 2.39 (2) keV, indicating that the main limitation of the spectroscopy system employed is electronic noise. As this is a promising detector not only for low-energy photons, but also for charged particles, the response of the BPX 65 has been investigated with a low-dispersion electron beam with energies between 20 and 100 keV. Under such conditions, the response function cannot be described as a simple Gaussian distribution. Moreover, the analytical response functions for electrons presented in the literature need to be generalized including a polynomial term. The proposed response function was tested and the behavior of the free parameters with the energy of the impinging electron is shown to be smooth. Thus, it is possible to extract from the data a well behaved parametrization.
TL and OSL response of CaF2:Tm for electron beam radiation processing
2018 - ASFORA, VIVIANE K.; ANTONIO, PATRICIA L.; GONÇALVES, JOSEMARY A.C.; BARROS, VINICIUS S.M. de; BUENO, CARMEN C.; KHOURY, HELEN J.; CALDAS, LINDA V.E.
The use of electron beams for industrial applications has increased worldwide requiring accurate dosimetry systems to assure the quality of irradiated products. The radiochromic films and alanine/EPR dosimeters are often employed in electron beam radiation processing. The thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimeters are mainly used for the electron beam dosimetry for radiotherapy applications. The aim of this work is to study the TL and infrared stimulated luminescence (IRSL) response of the calcium fluoride dosimeter doped with thulium (CaF2:Tm) for electron beam radiation processing. The pellets of CaF2:Tm (6mm in diameter and 1mm thickness) were produced via the solution combustion synthesis technique at the Nuclear Energy Department - UFPE. The individual TL and OSL sensitivities of a bach of these dosimeters were previously evaluated and 50 pellets with a standard deviation of 6% were selected to be used in this study. Irradiation was performed at the Radiation Technology Center at IPEN-CNEN/SP using 1.5MeV electron beam from a DC 1500/25/4 – JOB 188 accelerator covering the dose rate range 2-32kGy/s and doses from 0.5kGy up to 10kGy. The TL and OSL readings were carried out after a preheating at 100°C during 15min using a Riso TL/OSL reader, model DA-20. The TL measurements were taken with a heating rate of 2°C/s, in the range from 50°C to 350°C. The OSL readings were carried out with infrared stimulation with optical power attenuated to 20% during 240s. Residual thermoluminescent glow curves for IRSL were recorded after stimulation times. The reproducibility and stability of the TL and IRSL responses were also evaluated, as well as the dependence with different dose rates from 2kGy/s up to 32kGy/s. The results showed a deconvoluted TL glow curve with four components, being the main two TL peaks centred in the regions of 150°C and 200°C. The area of the TL peaks increases linearly with the absorbed dose up to 6kGy for all the dose rates evaluated. For doses higher than 6kGy, the TL response is sublinear with saturation around 10kGy. The IRSL curves of the dosimeters present a fast and a slow decaying IRSL signals. The total area of IRSL curves were measured for both different doses and dose rates. The correspondent results were linearly dependent on the absorbed dose and saturated in almost 10kGy. The IRSL residual TL glow curves exhibited a symmetrical decrease to the growing OSL signal. All the results presented regarding TL and IRSL response of CaF2:Tm have shown that these dosimeters are suitable for electron beam dosimetry in radiation processing.