An extrapolation chamber for the establishment of a primary radiation standard in 85Kr and 147Pm beta radiation beams
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2019
Autores IPEN
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INTERNATIONAL CONFERENCE ON DOSIMETRY AND ITS APPLICATIONS, 3rd
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Introduction
At the Calibration Laboratory (LCI) of the IPEN/CNEN, studies are in development on the
establishment of the Böhm extrapolation chamber model 23392 as a primary standard system
for the dosimetry and calibration of beta-radiation sources and detectors. This chamber was
already characterized at the LCI in 90Sr/90Y beams using two different entrance windows: one
of aluminized Mylar and another of Hostaphan. This extrapolation chamber was characterized
in 85Kr and 147Pm beams. All tests were carried out with the reference 90Sr /90Y source, for
comparative purposes.
Methods
A Keithley model 6517B electrometer was used for the measurements. The utilized radiation
sources are part of the Beta Secondary Standard BSS2. Moreover, the Monte Carlo code MCNP5
was used to determine the absorbed dose rates and to compare them with the experimentally
determined dose rates and with those from the PTB calibration certifi cate.
Results
Saturation curves, ion collection effi ciency, ion recombination, polarity effect, response
stability, real null depth, linearity of response, variation of response as a function of sourcedetector
distance, extrapolation curves, correction factors and absorbed dose rates were
obtained. The ion collection effi ciency was greater than 99%; the ionic recombination was less
than 1%, and the polarity effect was greater than 1%. The stability of the response was lower
than 0.15% for the repeatability test, and it was less than 0.36% for the reproducibility test.
The difference between the experimental absorbed dose rates and those from the Monte Carlo
model, compared to those from the calibration certifi cate, was less than 1.9% for all sources.
Conclusions
All results of the performed tests are within the limits of the international recommendations.
The results for the 90Sr/90Y source were in the good agreement with previous works performed at
LCI. These results are suitable for the establishment of a primary standard for beta radiation.
Como referenciar
POLO, IVON O.; SANTOS, WILLIAM S.; CALDAS, LINDA V.E. An extrapolation chamber for the establishment of a primary radiation standard in 85Kr and 147Pm beta radiation beams. 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/123456789/31013. Acesso em: 25 Apr 2024.
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.