NRL REPORT 6374 ‘ments ations rs fol‘0 0500+ ° be ghter ’ the IOQ00 -— 9000}- | | the ‘Onwas Ing ABSORBER \ \ =~ \ ° 2 o 1Ci) TOTAL B COUNTS DURING INITIAL DECAY PERIOD (ty-;)) b Ww or o sooo oO i | eo NO ' \ \ 1 1 \ rar ENT RE | 5-MIL Al ABSORBER ° 9 o ENrem oR aR ee oO oO o 2 oO o ° ° o \ 2000;- IOOO;- 03 04 05 06 O7 0.8 COUNTING RATE PATIO ter-7I74, i" 03 1.0 Fig. 7 — Effect of absorber thickness on the relationship between the total counts during theinitial period (¢1-11) and the ratio of the counting rates at tg-71 and ¢;.,, and for a radon concentration of 100 pCi/m? and a filtration rate of 1 m/min for 20 min.