Radiation Safety 201.. - Voss Associates

Exposure Rate from a Disk Source2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = R/hr @ 1 meter per CiA a = activity per unit area (curies per sq. meter)R = radius of source surface in metersD = distance from source surface in metersexample: Assume you have a liquid rad material spillthat has a consistent concentration of Be-7.2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = Be-7 is 0.0303 R/hr @ 1 meter per CiA a = 1 Curie per square meterR = 5 metersD = 1 meter distance above the surface of the spill2 2 2 2R/hr = ðR (0.0303) x 1 Ci/sq. meter x ln[(R + D )/D ]2R 2The R at top and bottom cancel each other.R/hr = 3.14 x 0.0303 x 3.26R/hr = 0.31 R/hrW hat would the source read at a distance of 1 meter if itwas a point source?Exposure Rate from a Disk Source2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = R/hr @ 1 meter per CiA a = activity per unit area (curies per sq. meter)R = radius of source surface in metersD = distance from source surface in metersexample: Assume you have a liquid rad material spillthat has a consistent concentration of Be-7.2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = Be-7 is 0.0303 R/hr @ 1 meter per CiA a = 1 Curie per square meterR = 5 metersD = 1 meter distance above the surface of the spill2 2 2 2R/hr = ðR (0.0303) x 1 Ci/sq. meter x ln[(R + D )/D ]2R 2The R at top and bottom cancel each other.R/hr = 3.14 x 0.0303 x 3.26R/hr = 0.31 R/hrW hat would the source read at a distance of 1 meter if itwas a point source?2121Exposure Rate from a Disk Source2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = R/hr @ 1 meter per CiA a = activity per unit area (curies per sq. meter)R = radius of source surface in metersD = distance from source surface in metersexample: Assume you have a liquid rad material spillthat has a consistent concentration of Be-7.2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = Be-7 is 0.0303 R/hr @ 1 meter per CiA a = 1 Curie per square meterR = 5 metersD = 1 meter distance above the surface of the spill2 2 2 2R/hr = ðR (0.0303) x 1 Ci/sq. meter x ln[(R + D )/D ]2R 2The R at top and bottom cancel each other.R/hr = 3.14 x 0.0303 x 3.26R/hr = 0.31 R/hrW hat would the source read at a distance of 1 meter if itwas a point source?21Exposure Rate from a Disk Source2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = R/hr @ 1 meter per CiA a = activity per unit area (curies per sq. meter)R = radius of source surface in metersD = distance from source surface in metersexample: Assume you have a liquid rad material spillthat has a consistent concentration of Be-7.2 2 2 2 2aR/hr = ðR A Ã x ln[(R + D ) / D ]/RÃ = Be-7 is 0.0303 R/hr @ 1 meter per CiA a = 1 Curie per square meterR = 5 metersD = 1 meter distance above the surface of the spill2 2 2 2R/hr = ðR (0.0303) x 1 Ci/sq. meter x ln[(R + D )/D ]2R 2The R at top and bottom cancel each other.R/hr = 3.14 x 0.0303 x 3.26R/hr = 0.31 R/hrW hat would the source read at a distance of 1 meter if itwas a point source?21