Navegação por Autores IPEN "BUENO, CARMEN C."

Classificar por: Ordenar: Resultados:

  • IPEN-DOC 15333

    RIDENTI, MARCO A.; PASCHOLATI, PAULO R.; LIMA, IARA B.; VIVALDINI, TULIO C.; BOTELHO, SUZANA; GONCALVES, JOSEMARY A.C. ; BUENO, CARMEN C. . Automation and instrument control applied to an experimental study of electron transport dynamics in an avalanche mode resistive plate chamber. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 9th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 16th; MEETING ON NUCLEAR INDUSTRY, 1st, September 27 - October 2, 2009, Rio de Janeiro, RJ. Proceedings... Sao Paulo: ABEN, 2009, 2009.

    Palavras-Chave: data acquisition systems; data acquisition; electrometers; electrons; experimental data; gases; ionization chambers; plates; programming languages; r codes

    Como referenciar este item
    Icon

  • IPEN-DOC 27157

    GONZALES-LORENZO, CARLOS D.; WATANABE, SHIGUEO; CAVALIERI, TASSIO A. ; CANO, NILO F.; RAO, T.K.G.; CHUBACI, JOSE F.D.; CARMO, LUCAS S. ; BUENO, CARMEN C. . Calculated and experimental response of calcium silicate polycrystalline to high and very-high neutron doses. Radiation Physics and Chemistry, v. 172, p. 1-7, 2020. DOI: 10.1016/j.radphyschem.2020.108820

    Abstract: In the scope to the discovery of new detectors for high and very-high gamma and neutron radiation dose (mGy- MGy), synthetic polycrystals of CaSiO3 have been produced by the devitrification method in our laboratory. CaSiO3 polycrystals were irradiated with thermal, epithermal and a small fraction of fast neutrons. In the position of irradiation, the thermal neutron flux is about 83% of the total neutron flux and the thermal neutron fluences range from 5.82 × 1013 to 2.97 × 1016 n/cm2. This thermal neutron reacts with Ca, Si and O through (n,γ) process, all or part of the gamma emitted in this reaction is absorbed by the sample and is responsible for the induction of thermoluminescence (TL). The total energy emitted by the (n,γ) reaction was calculated analytically. Furthermore, Monte Carlo simulations using MCNP5 radiation transport code was carried out to calculate the deposited dose on CaSiO3 by the neutron interaction finding doses ranging from 42 Gy to 21 kGy. CaSiO3 TL glow curves, after radiation exposure from the reactor, display the main prominent TL peak around 234–259 °C and when exposed to gamma radiation (Co-60) it shows the main TL peak around same 234–272 °C.

    Palavras-Chave: thermoluminescence; calcium silicates; polycrystals; neutron dosimetry; monte carlo method; thermal neutrons; neutron reactions; irradiation; reactors; direct reactions

    Como referenciar este item
    Icon

  • IPEN-DOC 30111

    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.. Characterization of a commercial PIN diode for radiotherapy photon beam dosimetry. In: INTERNATIONAL CONFERENCE ON DOSIMETRY AND ITS APPLICATIONS, 4th, October 16-20, 2023, Valencia, Spain. Abstract... Valencia, Spain: ISIRYM, 2023. p. 47.

    Como referenciar este item
    Icon

  • IPEN-DOC 28862

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Characterization of a thin photodiode as a routine dosimeter for low-dose radiation processing applications. Radiation Physics and Chemistry, v. 198, p. 1-7, 2022. DOI: 10.1016/j.radphyschem.2022.110200

    Abstract: The characterization of a dosimetry system based on a commercial PIN photodiode as a routine dosimeter in a 60Co industrial facility is reported. The main parameters of the dose rate response (repeatability, reproducibility, and angular dependence) and the dose response (dependence on both dose rate and accumulated dose) are investigated. The results obtained, within a dose rate range of 3.7–52.8 Gy/h and doses up to 200 Gy, fully adhere to the standard protocols established for radiation processing dosimetry. The diode performance as a routine dosimeter is validated by the good overall agreement with radiochromic films and alanine dosimetry.

    Palavras-Chave: photodiodes; thin films; gamma radiation; dosimetry; silicon diodes

    Como referenciar este item
    Icon

  • IPEN-DOC 26135

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Comparative evaluation of the performance of thin diodes used as on-line dosimeters in radiation processing applications. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 192-197.

    Abstract: 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.

    Palavras-Chave: cobalt 60; comparative evaluations; dose rates; dosemeters; electrical faults; gamma radiation; performance; photodiodes; sensitivity

    Como referenciar este item
    Icon

  • IPEN-DOC 19499

    ALVES, NELSON M.; MOSCA, RODRIGO C.; FERREIRA, DANILO C.; SOMESSARI, ELIZABETH S.R. ; SILVEIRA, CARLOS G. da ; DORNELLES, LEONARDO D.P.; BUENO, CARMEN C. ; MATHOR, MONICA B. . Comparision of dosimetric mapping of radiation induced skin ulcer animal model in nud mice and wistar rat. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 11th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 18th; MEETING ON NUCLEAR INDUSTRY, 3rd, November 24-29, 2013, Recife, PE. Proceedings... Sao Paulo: ABEN, 2013, 2013.

    Palavras-Chave: dosimetry; rats; animal cells; biological models; ionizing radiations; skin; ulcers; radiation injuries; mapping

    Como referenciar este item
    Icon

  • IPEN-DOC 24139

    CAMARGO, FABIO de; GONÇALVES, JOSEMARY A.C. ; BUENO, CARMEN C. . A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: 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.

    Palavras-Chave: absorbed radiation doses; cobalt 60; comparative evaluations; dose rates; gamma dosimetry; oxygen; radiation dose ranges; radiation dose units; silicon diodes; zone melting

    Como referenciar este item
    Icon

  • IPEN-DOC 26209

    PETRI, ANNA R.; BARROS, SUELEN F.; GONCALVES, JOSEMARY A.C. ; BUENO, CARMEN C. ; MAIDANA, NORA; MARTINS, MARCOS N.; VANIN, VITO R.. Count rate effect on the response of a low-cost PIN diode for electron spectrometry. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 1207-1213.

    Abstract: 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.

    Palavras-Chave: electron beams; si semiconductor detectors; semiconductor diodes; silicon diodes; counting rates; electron beams; photodiodes; electron diffraction; energy spectra; electron detection; electron spectroscopy

    Como referenciar este item
    Icon

  • IPEN-DOC 25530

    GONÇALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Current response stability of a commercial PIN photodiode for low dose radiation processing applications. In: RUBIO, MARCELO (Ed.); TIRAO, GERMAN (Ed.) INTERNATIONAL SYMPOSIUM ON RADIATION PHYSICS, 14th, October 7-11, 2018, Córdoba, Argentina. Abstract... Córdoba: Centro de Excelencia en Productos y Procesos, 2018. p. 308-308.

    Abstract: The increasing interest in low-dose (<100 Gy) radiation processing applications, as irradiation of blood for transplants and substerelization of insects, has demanded efforts to develop reliable dosimetry systems with high sensitivity, good spatial resolution and stable response over the range of 5-100 Gy. Silicon diodes fulfil these requirements and their uses in diodebased dosimeters are deemed appropriate with the advantage of providing prompt dose-rate and dose results. However, due to the low radiation tolerance of such dosimeters, they are rarely employed in radiation processing, where absorbed doses of tens of kGy can be easily achieved in regular applications. Experimentally, the low radiation hardness of ordinary silicon diodes operating in current mode manifests itself in a rapid drop of their current sensitivities with increasing accumulated doses. This effect is physically attributed to the decrease of the diffusion length of minority charge carriers, due to traps and defects induced by radiation in the silicon bulk, leading to the decrease of sensitive volume of the diode. Consequently, it is expected that thin diodes (with negligible thickness compared with the minority carrier diffusion lengths) are almost insensitive to variations of diffusion lengths and hence more resistant to radiation damage effects. From this assumption, a semiconductor dosimeter system was developed based on a commercial thin photodiode (type SFH206K) in a p-layer/intrinsic/n-layer (PIN) structure operating in short-circuit current mode. In this work, the response of this diode as a dose-rate meter has been investigated with respect the linearity between dose-rate and current, particularly addressing the stability of the current sensitivity with the absorbed dose. The dose was gathered off-line by the integration of the current signal during the exposure time. Irradiations were performed in both 60Co facilities of Panoramic and Gamma Cell types, covering the dose-rate range 8-660 Gy/h. The current-response of the diode proved to be linearly dependent on the dose-rate characterized by a current sensitivity of 0.2 nA.h/Gy. The stability of the current delivered by the diode for each dose-rate was evaluated as a function of the absorbed dose in several steps from 100 Gy to 15 kGy. In all measurements, current intensities were stable during the exposure time and proportional to the dose-rates with sensitivities variation less than 5% (k=2). In an attempt to lend further theoretical support to these results, calculations of the current generated in the sensitive volume of the diode were performed taking into account its dimensions, dose-rates and the values of diffusion lengths available in the literature. Good agreement between theoretical and experimental results was achieved.

    Como referenciar este item
    Icon

  • IPEN-DOC 27204

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Current response stability of a commercial PIN photodiode for low dose radiation processing applications. Radiation Physics and Chemistry, v. 167, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2019.04.026

    Abstract: This work investigates the on-line response of a thin diode, for monitoring low dose radiation processing, with respect to the linearity between current and dose-rate, the most interesting part being the variation of the current sensitivity with the accumulated dose. The results obtained indicate that the current response of this diode is linear and quite stable with repeatability better than 0.2% and a slight decay of 5% of the current sensitivity (0.28 nA h/Gy) for doses up to 15 kGy. In an attempt to give theoretical support to these results, the radiation induced current is calculated as a function of the dose rate assuming the diode to be thin as compared with the standard values of the minority carrier diffusion lengths in intrinsic silicon. Agreement within 2% is found between calculations and experimental data.

    Palavras-Chave: dose rates; radiation doses; low dose irradiation; dosimetry; silicon diodes; thin films; photodiodes; radiation monitoring

    Como referenciar este item
    Icon

  • IPEN-DOC 24060

    GONÇALVES, JOSEMARY A.C. ; BARROS, VINICIUS S.M.; ASFORA, VIVIANE K.; KHOURY, HELEN J.; BUENO, CARMEN C. . Diagnostic X-ray dosimeters using standard float zone (FZ) and XRA-50 commercial diodes. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: 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.

    Palavras-Chave: beams; comparative evaluations; diagnosis; dose rates; energy dependence; sensitivity; silicon diodes; zone melting

    Como referenciar este item
    Icon

  • IPEN-DOC 29098

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Dose rate mapping of an industrial 60Co irradiator using an online photodiode-based dosimetry system. Radiation Physics and Chemistry, v. 200, p. 1-6, 2022. DOI: 10.1016/j.radphyschem.2022.110387

    Abstract: In this work, a housemade dosimetry system based on a thin photodiode is applied for online mapping of dose rates, between 2.6 and 37.7 Gy/h, delivered by a Panoramic 60Co industrial facility. The operational principle of the dosimeter relies on the real-time acquisition of the induced currents from the irradiated diode operating in the short-circuit mode without externally applied voltage. The radial mapping of the radiation field is performed by rotating the diode around the central axis of the panoramic irradiator, covering 360° at intervals of 18°. The results are benchmarked with alanine dosimeters, Monte Carlo simulations, and reference dose rates retrieved from the facility calibration. The overall consistency of the whole data complies with the maximum response variation (8%, k = 2) recommended by the International Standard Protocols for routine dosimeters in radiation processing dosimetry. 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.

    Palavras-Chave: dose rates; dosemeters; photodiodes; irradiation; cobalt 60; dosimetry

    Como referenciar este item
    Icon

  • IPEN-DOC 30116

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; POTIENS, MARIA P.A. ; CALDAS, LINDA V.E. ; BUENO, CARMEN C. . Dosimetric parameters and radiation tolerance of epitaxial diodes for diagnostic radiology and computed tomography X-rays. In: INTERNATIONAL CONFERENCE ON DOSIMETRY AND ITS APPLICATIONS, 4th, October 16-20, 2023, Valencia, Spain. Abstract... Valencia, Spain: ICDA, 2023. p. 49.

    Como referenciar este item
    Icon

  • IPEN-DOC 21075

    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 dosimetric survey of the DC1500/25/04 electron beam plant installed at IPEN-CNEN/SP. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: brazilian cnen; accelerators; alanines; chemical dosemeters; electron beams; electron spin resonance; radiation doses; quality assurance; iso; dosimetry

    Como referenciar este item
    Icon

  • IPEN-DOC 23776

    SOMESSARI, SAMIR L. ; KUNTZ, FLORENT; SILVEIRA, CARLOS ; BUENO, CARMEN C. ; NAPOLITANO, CELIA M. ; CALVO, WILSON A.P. ; GONÇALVES, JOSEMARY A.C. . A dosimetric survey of the DC1500/25/04 electron beam plant installed at IPEN-CNEN/SP. In: INTERNATIONAL MEETING ON RADIATION PROCESSING, 18th, November 07-11, 2016, Vancouver, BC, Canada. Abstract... 2016.

    Abstract: In this work we describe a dosimetric survey of the DC1500/25/04 electron beam accelerator installed in the Intense Sources of Radiation Laboratory at IPEN/CNEN-SP. As this accelerator has been used for innumerable applications in radiation processing, product surface and internal doses must be targeted and controlled via operational qualification such as beam energy, beam current, scan width and conveyor speed. The qualification was carried out in order to observe the current performances of the irradiation plant using Alanine (ESR) and CTA (UV Spectrophotometry) dosimeters. Energy (Electron penetration in material) calculations, scanning width/length, homogeneity and irradiation uniformity were evaluated according to ISO/ASTM 51649 and ISO11137-3, as well as process uncertainty establishment.

    Palavras-Chave: accelerators; alanines; chemical dosemeters; dosimetry; electron beams; electron spin resonance; brazilian cnen; iso; quality assurance; radiation doses

    Como referenciar este item
    Icon

  • IPEN-DOC 21124

    ALVES, NELSON M. ; FUNARI, ANA P. ; MIRANDA, JURANDIR T. ; NAPOLITANO, CELIA M. ; GONCALVES, JOSEMARY A.C. ; BUENO, CARMEN C. . Dosimetry of an animal irradiation system. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: dosimetry; irradiation; ionizing radiations; mice; necrosis; dermatitis; radiotherapy; radiation dose units; side effects; alanines; cobalt 60

    Como referenciar este item
    Icon

  • IPEN-DOC 24098

    PETRI, ANNA R. ; MANGIAROTTI, ALESSIO; GONÇALVES, JOSEMARY A.C. ; BUENO, CARMEN C. . Effect of the ohmic drop in a RPC-like chamber for measurements of electron transport parameters. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: 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.

    Palavras-Chave: charged-particle transport; dielectric materials; electric conductivity; electric potential; electrodes; electrons; mesh generation; voltage drop

    Como referenciar este item
    Icon

  • IPEN-DOC 18846

    FERREIRA, DANILO C.; BUENO, CARMEN C. . Evaluation of silicon dosimetry parameters in Co-60 gamma irradiation facilities. In: VANIN, VITO R. (Ed.) BRAZILIAN WORKSHOP ON NUCLEAR PHYSICS, 33rd, September 7-11, 2010, Campos do Jordão, SP. Proceedings... American Institute of Physics, 2010. p. 233-236.

    Palavras-Chave: cobalt 60; dose rates; dosemeters; doses; evaluation; gamma dosimetry; gamma radiation; photovoltaic effect; semiconductor diodes; sensitivity; si semiconductor detectors

    Como referenciar este item
    Icon

  • IPEN-DOC 27745

    ASFORA, VIVIANE K.; ANTONIO, PATRICIA L. ; GONCALVES, JOSEMARY A.C. ; BUENO, CARMEN C. ; BARROS, VINICIUS S.M. de; OLIVEIRA, CHARLES N.P.; CALDAS, LINDA V.E. ; KHOURY, HELEN J.. Evaluation of TL and OSL responses of CaF2:Tm for electron beam processing dosimetry. Radiation Measurements, v. 140, p. 1-8, 2021. DOI: 10.1016/j.radmeas.2020.106512

    Abstract: The thermoluminescence (TL) and infrared stimulated luminescence (IRSL) responses of in-house produced CaF2:Tm dosimeters are investigated in this work, envisaging their application in electron beam (EB) radiation processing. The irradiations were performed at an industrial EB accelerator (1.5 MeV) covering a dose rate range of 2–8 kGy/s and dose up to 10 kGy. In general, the TL glow curves display four peaks, termed as peaks 2, 3, 4, and 5, corresponding to temperatures at ~150, 200, 240, and 300 °C, respectively. The intensity of the low-temperature peaks (2 and 3) grows with the dose, while the others remain constant (saturated). Nevertheless, an evident dose effect on the glow curves manifests in decreased peak3/peak2 ratio with increasing doses. The CW-IRSL curves exhibit similar patterns with an initial signal increase, followed by an exponential decay. Instead of the normal monotonic decays, these peak-shaped curves might be due to the charge capture competition between empty shallow traps and recombination centers. Both TL and IRSL intensities increase linearly with doses up to 6 kGy, and for higher doses, they become sub-linear with a saturation trend around 10 kGy. Another common feature of TL/IRSL response is its dose rate dependence, being more sensitive at higher dose rates. Despite being dose-rate dependent, the CaF2:Tm dosimeters might be suitable for EB processing dosimetry. However, for their use as routine dosimeters, relevant dosimetric characteristics, such as fading and response reproducibility, have to be investigated. Work in this direction is underway.

    Palavras-Chave: thermoluminescence; infrared radiation; luminescence; electron dosimetry; calcium fluorides; dosimetry; irradiation; evaluation

    Como referenciar este item
    Icon

  • IPEN-DOC 24059

    NASCIMENTO, CRISTINA R.; ASFORA, VIVIANE K.; BARROS, VINICIUS S.M.; GONÇALVES, JOSEMARY A.C. ; ANDRADE, LUCAS F.R.; KHOURY, HELEN J.; BUENO, CARMEN C. . Feasibility studies of using thin entrance window photodiodes for clinical electron beam dosimetry. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: 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.

    Palavras-Chave: depth dose distributions; electron beams; energy dependence; feasibility studies; ionization chambers; mev range 01-10; photodiodes; silicon diodes

    Como referenciar este item
    Icon

A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

✔ É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

✔ A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

✔ Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

✔ Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

✔ 95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

✔ Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

✔ O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

✔ Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

✔ Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.