Dosimetric characterization of thin diodes in an electron beam facility for radiation processing
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2019
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INTERNATIONAL CONFERENCE ON DOSIMETRY AND ITS APPLICATIONS, 3rd
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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.
Como referenciar
GONCALVES, J.A.C.; MANGIAROTTI, A.; ASFORA, V.K.; KHOURY, H.J.; BUENO, C.C. Dosimetric characterization of thin diodes in an electron beam facility for radiation processing. In: INTERNATIONAL CONFERENCE ON DOSIMETRY AND ITS APPLICATIONS, 3rd, May 27-31, 2019, Lisboa, Portugal. Abstract... Lisboa, Portugal: C2TN, Instituto Superior Técnico, Universidade de Lisboa, 2019. Disponível em: http://repositorio.ipen.br/handle/123456789/31014. Acesso em: 20 Mar 2026.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.