A.3—
VARIATIONS OF RESPONSE DUE TO LEAD-FILTER THICKNESS
The Radiological Equipment Section has also found that in the low-energy region the
variation in response due to variations in lead thickness is quite considerable but not prohibitive. There is practically no variation of response with lead thickness for energies above
1 Mev. Unfortunately vendors are unable to meet 10 per cent tolerances,
Exposure needed to obtain unit density
behind various lead thicknesses, r
A.4.
0.72 mm
0.65 mm
Effective
radiation energy
D-502
D-606
D-502
0.07
0.12
0.17
0.21
1.25
0.80
1.08
1.11
1,22
1.23
32.0
45.0
43.7
44.3
47.0
0.98
1.28
1.22
1.31
1.23
0.79 mm
D-606
— 39.0
§4.0
49.0
45.0
47.0
D-502
D-606
1.18*
1.57
1.33*
1.40
1.23
45.5*
62.2*
54.4*
45.7*
47.0
VARIATIONS BETWEEN 559 PACKETS AND PROJECT EXPERIMENTAL BADGES
Discussions on variances between the test badge and experimental project badges led to a
controlled comparison utilizing 364 pc of Co® for a time period of 100 min and 45 sec ata
distance of 40 cm. Calculated dosage was 5103 mr.
Film type: Du Pont 502-606; emulsion 559-107
densitometer
reading
Actual
dosage
Variation from
36
37
38
39
2.50
2.49
2.49
2.47
5819
5785
5765
5615
13.9
12.9
12.9
10.03
30
29
28
27
2.55
2.52
2.46
2.49
6215
6085
5515
5765
21.8
19.2
8.06
12.9
26
25
24
23
2.52
2.51
2.55
2.50
-6085
5915
6215
§815
19.2
15.9
21.8
13.9
22
21
20
2.49
2.49
2.46
0.26
5765
5765
5515
85
12.9
12.9
8.06
Control
Average
calculation, %
14,42
* Extrapolated,
62
seni
Average
Film
badge