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Poster — Thur Eve — 66: Investigation of Shielding Property Changes in Curing High Density Concrete
Author(s) -
Marsh M,
Peters C,
Rawluk N,
Schreiner LJ
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3476171
Subject(s) - electromagnetic shielding , materials science , attenuation , bunker , composite material , property value , half value layer , beam (structure) , curing (chemistry) , optics , radiation shielding , physics , coal , real estate , political science , law , engineering , waste management
Our centre is currently undergoing a major expansion, including the construction of two new linear accelerator radiotherapy bunkers and the addition of extra shielding to existing bunkers. While shielding material is typically specified by Tenth‐Value Layer (TVL) at the design stage, the concrete supplier will specify the (wet) densities of the concrete constituents, and the concrete testing lab will verify the as‐cast material by its dry (cured) density. Thus, the relationship between the intended TVL and the actual performance of the shielding material might not be entirely clear. In this study, cylindrical samples of the high‐density shielding concrete were taken as each section was poured. The shielding performance of the samples (measured by beam attenuation and TVL) was evaluated for 15 MV and 6 MV X‐ray beams, and for the 1.25 MeV monoenergetic gamma beam from a Cobalt‐60 (Co‐60) source. The samples were also imaged and analyzed using Cobalt‐60 Cone Beam Computed Tomography (CoCBCT). Results indicate no significant change in the TVL of high‐density concrete samples as they cure. The minor fluctuations in shielding properties observed are explained by the heterogeneous structure of the samples as indicated in the CoCBCT images.