Ernest Rutherford (1908) an English physicist bombarded a ...
Airborne Radioactivity By Beth Harmony. Reasons for the experiment: Radiation is something that we...
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Transcript of Airborne Radioactivity By Beth Harmony. Reasons for the experiment: Radiation is something that we...
Airborne RadioactivityBy Beth Harmony
Reasons for the experiment:Radiation is something that we are constantly being
bombarded with from all directions. By taking a sample of the air, using a piece of filter paper, the amount of radiation that we breathe in can be estimated. The most common radiation that we are bombarded with is from radon 222, which comes up from the ground. Lead 214 is
a byproduct of the decay of radon 222, and is also heavy enough to get caught in the filter paper, making it a good candidate to look at.
How the experiment was done:A 62 cpm vacuum, with a piece of filter paper in it, was placed
in three different rooms, and ran for an hour and 20 minutes. The filter paper was then placed over a germanium detector, which detects
gamma radiation. The detector was run for 20 minutes, and then the peaks were analyzed. Each peak is associated with a specific energy,
and, in most cases, is unique to a single element. By looking at the peaks that are associated with lead 214, the amount of micro Ci/ml, the
amount of radiation in each milliliter, could be determined.
Source: Los Alamos Science
Uranium 238 Decay Series
Source: Cutnell and Johnson
Source: Los Alamos Science
Source: Los Alamos Science
Low Level Lab Sample 2-24-05 Live time 1191 seconds
Chalk Hill Sample taken 3-3-05 live time 1218 seconds
Keck Laboratory Sample taken 3-3-05 live time 1218 sec.
isotope Pb-214
gamma energy Raw Counts micro Ci/m(keV) under peak
Low Level Lab Sample 351.9 1090 6.646240E-11
Chalk Hill Sample351.9 570 3.475560E-11
Keck Lab Sample351.9 195 1.189010E-11
Detector Efficiency = 2.93%
Lead-214
AtomicNo. Radionuclide Class
Table 1Occupational Values
Table 2Effluent Concentrations
Table 3Releases toSewers
Col. 1 Col. 2 Col. 3 Col. 1 Col. 2
OralIngestionALI(µCi)
Inhalation
Air(µCi/ml)
Water(µCi/ml)
MonthlyAverageConcentration(µCi/ml)
ALI(µCi)
DAC(µCi/ml)
82 Lead-2142 D, all compounds 9E+3 8E+2 3E-7 1E-9 1E-4 1E-3
NRC Limits on Lead-214
Source: Radiological Health Handbook
Germanium Detector (red cover)Air filter paper (on lab book – darker circle)
Air sampling tool with clean white filter paper