16 LOCKHART AND PATTERSON TABLE A2 Calculated 8 Activity from 100 pCi of Radon per m? of Air Sampled at the Rate of | m?/min for 20 min . (min) Disintegrations 0-20 (p = 0 to 0.190) 40-60 (p = 0.355 to 0.478) 80-100 (po = 0.564 to 0.623) 0 (p = 0.735) . _. Activity Ratio Final/Initial Final Activity (61-71) Initial Activity (t1-11) Radon Age* {Countst Disintegrations Countst RaB RaC 7887 3778 {53.8 315.5 1755 3282 34.2 274.0 Total 11665 469.3 5037 308.2 RaB RaC 24177 21808 4741S 1821.0 5216 11057 1OL7 923.3 Total 45985 2292.5 16273 1025.0) RaB RaC 29976 33035 584.5 2758.4 6449 14403 125.8 1202.7 Total 63011 3342.9 20852 1328.5 RaB RaC 33221 41689 647.8 3481.0 7136 16562 139.2 1382.9 Total 74910 4128.8 23698 1522.1 Disintegrations Counts 0.432 0.657 0.354 0.447 0.331 0.397 0.316 0.369 *Conunuously changing age during the 20-min filtration period. Collected on plass fiber filter of 100% retentivity; counted through LO-mil aluminum absorber. Taste AS Age of the Radon/Radon Daughter Mixture Elapsed RaC/RaB Atom Ratio (p) Radon Concentration (pCi/m?) Time (min) Standard Procedure* Modified Procedure? Expected Valuef Standard Procedure*® Modified Proceduret Expected Vahuet 0-20 0.052 0.070 0.095 5.42 x 105 3.93 x 105 6.03 x 105 30-50 0.27 0.27 0.34 3.87 x 10 3.66 x 105 6.04 x 105 60-80 0.46 0.45 0.49 3.28 x 105 3.28 x 105 15.93 x 105 90-110 0.51 0.50 0.58 3.07 X 105 3.09 x 105 15.90 « 105 120-140 0.58 0.57 0.61 $3.19 x 105 3.22 x 105 15.89 x 105 150-170 0,60 0.59 0.63 3.06 x 105 3.09 x 105 $5.85 x 105 180-200 0.62 0.61 0.64 2.99 x 105 3.02 x 105 5.84 x 105 260-2806 0.67 0.66 0.70 2.94 x 105 2.96 x 108 6.01 x 105 285-305 0.63 0.62 0.67 2.45 x 105 2.48 x 105 5.81 x 105 *The value ofp is assumed to be constant during the sampling period. *The value of p is assumed to increase with the age of the radon conglomerate dunng collection. $Calculations based on modified procedure and taking in accint changes produced by removal of 11.8% of the aerosol with each sample. Cee ange caelRANTETS ee Comparison of Derived p Values and Radon Concentrations in the Small Chamber Run (Radon = 6.41 X 10° pCi/m3) Based on a Fixed and a Variable