Security Classification
DOCUMENT CONTROL DATA - R&D
{Security classification of title, body of abstract and indexing annotation must be entered when the overall reportia classified)
1. ORIGINATING ACTIVITY (Corporate authar)
Fe. REPORT SECURITY
U.S. Naval Research Laboratory
Washington, D.C, 20390
3
C LASSIFICA TION
Unclassified
lab GRouP
REPORT TITLE
THE EXTENT OF RADIOACTIVE EQUILIBRIUM BETWEEN RADON ANDITS
SHORT-LIVED DAUGHTER PRODUCTS IN THE ATMOSPHERE
4. DESCRIPTIVE NOTES (Type of report and inclusive dates)
An interim report on the problem.
§. AUTHOR(S) (Last name. firat name, initial)
Lockhart, L.B., Jr., and Patterson, R.L., Jr.
6. REPORT DATE
Ja. TOTAL NO. OF PAGES
8a. CONTRACT OR GRANT NO.
9a. ORIGINATOR'S REPORT NUMBER(S)
April 5, 1966
NRL Problem AQ2-13
&
7b. NO. OF AEFS
290
3
NRL Report 6374
PROJECT NO.
RR 004-02-42-5151
¢.
and AEC AT 49-7(2435)
9b. OTHER REPORT NO(S) (Any other numdera that may be assigned
thie report
d.
10. AVAILABILITY /LIMITATION NOTICES
Distribution of this document is unlimited.
11. SUPPL EMEN TARY NOTES
12. SPONSORING MILITARY ACTIVITY
Departmentof the Navy (Office of
‘
Naval Research) Washington, D.C.
13. ABSTRACT
A set of experimental conditions has been derived which optimizes the accuracy with which
the radon contentof the atmosphere andits apparent residence timethere can be determined
from measurementof the filterable gross 8 activity during two separate 10-minute periods
following the end of a 20-minute collection period.
The 20-minute collection is made ona filter of essentially 100% retentivity (glass fiber filter)
and countedfor @ activity through a 10-mil (70. mg/cm?) aluminum absorber on equipmentof
knownefficiency for the 8 particles emitted by RaB and RaC. Theratio of measured counts
during the 61-through-71-minute decay period to that during the 1-through-11-minute
period is emnloyed to obtain the atom ratio of RaC to RaB (p) in the air sar pled, the apparent
age (r) of the conglomerate of radon andits daughters, and the total counts to be expected
from any given radon concentration in the air.
Extensive examples of atmospheric measurements are given which suggest that under most
conditions in the free atmosphere radonis essentially at secular equilibrium with its daughter
products. Other collections made following addition of radon to a restricted volume show the
expected increase in p with time, which confirms the basic validity of the procedure.
DD .2%. 1473
7
Security Classification