Table 6.6. Gamma Dose Rates Measured with an Arm Phantom Placed Inside Gloves Dusted with Plutonium Dioxide Powder

DOE-STD-1128-98

Table 6.6.

Gamma Dose Rates Measured with an Arm Phantom Placed Inside Gloves Dusted

with Plutonium Dioxide Powder

Gamma Dose Rates, mrad/h

Neoprene Glove

Lead-Loaded Glove

Position

10.0 + 0.4

Palm

9.5 + 16

Back of Hand

21.8 + 1.3

5.4 + 0.3

Wrist

Inside

22.6 + 0.7

9.0 + 0.6

Outside

22.5 + 0.6

5.8 + 0.4

Forearm

Inside

34.5 + 0.2

6.7 + 0.4

Outside

16.7 + 0.2

3.6 + 0.6

Elbow

Inside

17.5 + 0.4

5.3 + 0.4

Outside

11.4 + 0.1

3.7 + 0.4

Front

---

4.4 + 0.3

Bottom of humerus

3.5 + 0.2

3.6 + 0.4

Lower mid-arm

6.7 + 0.5

3.4 + 0.2

Lower mid-humerus

2.1 + 0.2

2.9 + 0.3

Upper mid-arm

4.6 + 0.1

2.3 + 0.4

Upper mid-humerus

1.0 + 0.1

1.4 + 0.3

Top of arm

0.8 + 0.2

3.7 + 0.3

Top of humerus

---

1.1 + 0.3

6.2.2.2 Calculated Photon Dose Rates

It is very difficult to accurately calculate dose rates from plutonium

because of the wide range of photon energies and the relatively low

abundance of photons. Most of the photons are of relatively low

energies, usually below 425 keV, which are easily shielded. For heavily

shielded spectra, the high-energy photons from decay progeny become

very important, as well as the high-energy photons from plutonium,

which have very low abundances.

For this reason, there are only a few computer codes that give accurate

dose rates for plutonium. Many computer codes do not calculate the

photons from progeny from radioactive decay. Others do not include the

high-energy photons which have very low abundances, but which

become very important for massive shields. One must check the photon

libraries to make certain that the higher-energy photons are included.

Also, many point kernel codes may not give accurate results for thin

shields because low-energy build-up factors are not very accurate.

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