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Radiation Data | Conversion Factors for Weapons Grade Plutonium

Conversion Factors for Weapons Grade Plutonium

1. ASSUMPTIONS  

a. Conversions are for weapons grade plutonium only, with no americium.  

b. Density of soil 1.5 g/cm3.  

c. Specific activity (alpha only) 0.075 Ci/g.  

d. Contamination of soil is to the depth of 1 cm.  

2. CONVERSION TABLES  

Tables 1. through 6. provide a variety of conversion factors for weapons grade plutonium.  


Table  1. Conversion Factors for Weapons Grade Plutonium

Table 1. Conversion Factors for Weapons Grade Plutonium

a. The conversion of alpha instrument readings in CPM into quantifiable units is affected by the type of surface and meter efficiency.  For accurate conversions, a surface sample from the area measured should be analyzed with laboratory equipment, and the conversion factor for that area computed.  Table 2. provides approximate factors for converting alpha readings in CPM into µg/m2 for various surfaces using the equation:  µg/m2 - correction factor x CPM.    


Table 2. Approximate Factors for Converting Alpha Readings for Various Surface Types

Table 2. Approximate Factors for Converting Alpha Readings for Various Surface Types

b. The correction factors consider unit and area conversions, nominal instrument efficiency during field use, and assume a 60‑sq-cm probe area (PAC-1S).  Correction factors should be multiplied by four for use with the AN/PDR-56.  Tables 3. and 4. were prepared fromtable 1. and the equation in paragraph 2.a. for users of the AN/PDR-56.  


Table 3. Conversion Table (CPM to µg/m2 or µCi/m2) AN/PDR-56 Alpha Meter

Table 3. Conversion Table (CPM to µg/m2 or µCi/m2) AN/PDR­56 Alpha Meter *To convert µCi/m2 to Bq/m2, multiply by 3.7 x 104.


Table 4. Conversion Table (CPM to mg/m2 or mCi/m2) ADM-300

Table 4. Conversion Table (CPM to mg/m2 or mCi/m2) ADM-300


Table 5. Conversion Table (Megabequerel (MBq) to Millicuries (mCi)
and Microcuries µCi)

Table 5. Conversion Table (Megabequerel (MBq) to Millicuries (mCi) and Microcuries µCi)

     
Table 6. Conversion to International System Units

6


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