Evaluation of ionization chambers in X-ray beams used for instruments calibration
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2008
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INTERNATIONAL CONGRESS OF THE INTERNATIONAL RADIATION PROTECTION ASSOCIATION
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Resumo
The periodically evaluation of ionization chambers and quality control of standard X-ray beams used
for purpose to calibration is important to guarantee the calibration procedures of dosimeters and instruments used
in radiation protection, diagnostic radiology and radiotherapy routines to ensure that procedures are following the
national and international recommendations. Based on that, a quality control routine must be made periodically, to
guarantee the good working of these reference ionization chambers and X-ray beams. In this work was compared
the performance of different kind of ionization chambers in X-ray beams, level mammography. It has been used as
reference a 6 cm³ ionization chamber, from RadcalTM, with MylarTM window, specific for use in mammography
beams. The performance of that ionization chamber was compared with other two 180 cm³ (parallel plate
chambers) and two 6 cm³ (cylindrical type). The ionization chambers’ stability has been made using a 90Sr+90Y
radioactive source (20 MBq, 2007). After the stability control, the ionization chambers were placed on X-ray
beams, mammography level (25, 27.5 and 35 kV, and current of 30 mA), tungsten target with additional filtration
of 0.06 mm of molybdenum for direct beams, and plus 2 mm of aluminum for attenuated beams. The results show
that the 6 cm³ cylindrical ionization chambers have a maximum variation of 5.08% in the energies range studied,
the results show that they could be used as working standard in the calibration laboratory. The 180 cm³ ionization
chambers have an average variation of about 20% to direct beams, and about 7,8% to attenuated beams. It is
possible conclude, that the 180 cm³ ionization chambers are not very efficient to low energies measurements,
although they also can be used in diagnostic radiology X-ray qualities, but to higher energies, and can also be used
in radiation protection X-ray qualities.
Como referenciar
CORREA, EDUARDO de L.; POTIENS, MARIA da P.A.; CALDAS, LINDA V.E.; VIVOLO, VITOR. Evaluation of ionization chambers in X-ray beams used for instruments calibration. In: INTERNATIONAL CONGRESS OF THE INTERNATIONAL RADIATION PROTECTION ASSOCIATION, October 19-24, 2008, Buenos Aires, Argentina. Proceedings... Disponível em: http://repositorio.ipen.br/handle/123456789/15940. Acesso em: 30 Dec 2025.
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.