Development of collimator for in-situ measurement of 90Sr specific activity by β-ray survey meter and Monte Carlo calculation

For the in-situ measurement of 90Sr contamination, the collimators to be combined with the β-ray survey meter were designed with MCNP-4C calculations. The designed collimators were manufactured and its characteristics were measured in accordance with the calculations. The calculated energy deposition in the survey meter agreed within 27% to its counting rate measured in terms of their dependencies on the collimator dimension. This supports the usability of the manufactured collimators and numerical correction of the sensitivity of the survey meter depending on the geometry.