60Co γ-ray attenuation coefficient of barite concrete
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F. Bouzarjomehri , T. Bayat , M.H. Dashti R , J. Ghisari , N. Abdoli |
, Bouzarj_44@yahoo.com |
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Abstract: (18448 Views) |
ABSTRACT
Introduction: Recently uses of
medium and high energy x-rays has been increased in Iran and radiotherapy
centers along with a variety of accelerators have been installed in some
provinces. In the other hand there is no sufficient skill in designing and
making radiotherapy treatment rooms. This study was conducted to evaluate the
efficacy of different mixtures of barite concrete for shielding the radiotherapy
rooms. In this way we emphasized on determining the size and amount of barite
aggregations to achieve the maximum radiation attenuation which leads to
minimizing wall thickness in treatment room.
Materials and Methods: To
increase concrete density, the barite aggregation was added to concrete.
Different size variations of barite aggregates mixed with different water/cement
ratio were examined. The dimension of cubic concrete specimens for compression
strength test was 15×15×15 cm. The rectangular barite concrete blocks with
different compressions as used for strength test with cross section of 10×10 cm
and thicknesses from 5 to 40 cm were used for radiation attenuation test. For
this test concrete specimens were irradiated by gamma beam of 60Co
(Phoenix Theratron). The transmission radiation through the blocks was measured
by a Farmer ionization chamber (FC65P) in Yazd radiotherapy center.
Results: Our findings showed
that in all specimens the highest mean compression strength was related to the
specimens with equal ratio of fine to coarse barite aggregates but the lowest
HVL was obtained from mixtures with fine to coarse ratio of 35/65. The concrete
sample with a 0.45 water/cement ratio, 350 kg/m3 cement and equal
amounts of fine and coarse barite sands had nearly minimum half value layer(HVL)
and maximum compression strength, so this sample was considered as the best
barite concrete sample.
Conclusion: Since HVL of the
barite concrete specimens with the same compression strength is markedly lower
than the conventional concrete and we have a plenty barite mines in our country
it is recommended to use barite concrete with the best mixture condition based
on our findings for shielding the radiotherapy rooms. |
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Keywords: Barite Concrete, 60Co γ- rays, Radiation Protection, Shielding, Linear Accelerator |
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Full-Text [PDF 358 kb]
(6972 Downloads)
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Type of Study: Original Research |
Subject:
Radiation Biology
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