Activity in DPM vs Particle Size in microns
for oxide form of various isotopes
0.5
ì
1
ì
5
ì
10
ì
50
ì
U
8.7E-3
0.07
9
69.7
8700
234
U
3.0E-6
2.4E-5
3E-3
0.02
3
235
U
4.7E-7
3.8E-6
5E-4
3.8E-3
0.47
238
Np
1.0E-3
8.0E-3
1.0
8
1000
237
Pu
25
201
2.5E4
2E5
2.5E7
238
Pu
0.09
0.73
91
730
9.1E4
239
Pu
0.33
2.7
333
2670
3.3E5
240
Pu
151
1210
1.5E5
1.2E6
1.5E8
241
Am
5.1
41.1
5140
4.1E4
5.14E6
241
Calculating Activity vs Particle Size
1. Volume of the particle is
V = 1/6
ð
d .
3
2. Use the density of the isotope listed in this reference.
3. Mass of the particle is
M = V x density.
4. Activity of the particle is
A = M x specific activity.
Correct the activity of the particle for the oxide form if you need
that; the molecular weight of Pu
is 238, the activity of the
238
dioxide form must be reduced by the ratio of the molecular
weight of the dioxide form to the molecular weight of Pu
.
238
Multiply the calculated activity by 238/270 to get the activity of
the dioxide form.
For particles larger than about 1
ì
the aerodynamic diameter is
approximately equal to the physical diameter times the square
root of the density. The 10
ì
diameter particle in our example
would have an equivalent aerodynamic diameter of 34
ì
(10
ì
x
the square root of 11.46). This must be taken into account in air
sampling/monitoring situations.
4
4
Activity in DPM vs Particle Size in microns
for oxide form of various isotopes
0.5
ì
1
ì
5
ì
10
ì
50
ì
U
8.7E-3
0.07
9
69.7
8700
234
U
3.0E-6
2.4E-5
3E-3
0.02
3
235
U
4.7E-7
3.8E-6
5E-4
3.8E-3
0.47
238
Np
1.0E-3
8.0E-3
1.0
8
1000
237
Pu
25
201
2.5E4
2E5
2.5E7
238
Pu
0.09
0.73
91
730
9.1E4
239
Pu
0.33
2.7
333
2670
3.3E5
240
Pu
151
1210
1.5E5
1.2E6
1.5E8
241
Am
5.1
41.1
5140
4.1E4
5.14E6
241
Calculating Activity vs Particle Size
1. Volume of the particle is
V = 1/6
ð
d .
3
2. Use the density of the isotope listed in this reference.
3. Mass of the particle is
M = V x density.
4. Activity of the particle is
A = M x specific activity.
Correct the activity of the particle for the oxide form if you need
that; the molecular weight of Pu
is 238, the activity of the
238
dioxide form must be reduced by the ratio of the molecular
weight of the dioxide form to the molecular weight of Pu
.
238
Multiply the calculated activity by 238/270 to get the activity of
the dioxide form.
For particles larger than about 1
ì
the aerodynamic diameter is
approximately equal to the physical diameter times the square
root of the density. The 10
ì
diameter particle in our example
would have an equivalent aerodynamic diameter of 34
ì
(10
ì
x
the square root of 11.46). This must be taken into account in air
sampling/monitoring situations.
4
4
Activity in DPM vs Particle Size in microns
for oxide form of various isotopes
0.5
ì
1
ì
5
ì
10
ì
50
ì
U
8.7E-3
0.07
9
69.7
8700
234
U
3.0E-6
2.4E-5
3E-3
0.02
3
235
U
4.7E-7
3.8E-6
5E-4
3.8E-3
0.47
238
Np
1.0E-3
8.0E-3
1.0
8
1000
237
Pu
25
201
2.5E4
2E5
2.5E7
238
Pu
0.09
0.73
91
730
9.1E4
239
Pu
0.33
2.7
333
2670
3.3E5
240
Pu
151
1210
1.5E5
1.2E6
1.5E8
241
Am
5.1
41.1
5140
4.1E4
5.14E6
241
Calculating Activity vs Particle Size
1. Volume of the particle is
V = 1/6
ð
d .
3
2. Use the density of the isotope listed in this reference.
3. Mass of the particle is
M = V x density.
4. Activity of the particle is
A = M x specific activity.
Correct the activity of the particle for the oxide form if you need
that; the molecular weight of Pu
is 238, the activity of the
238
dioxide form must be reduced by the ratio of the molecular
weight of the dioxide form to the molecular weight of Pu
.
238
Multiply the calculated activity by 238/270 to get the activity of
the dioxide form.
For particles larger than about 1
ì
the aerodynamic diameter is
approximately equal to the physical diameter times the square
root of the density. The 10
ì
diameter particle in our example
would have an equivalent aerodynamic diameter of 34
ì
(10
ì
x
the square root of 11.46). This must be taken into account in air
sampling/monitoring situations.
4
4
Activity in DPM vs Particle Size in microns
for oxide form of various isotopes
0.5
ì
1
ì
5
ì
10
ì
50
ì
U
8.7E-3
0.07
9
69.7
8700
234
U
3.0E-6
2.4E-5
3E-3
0.02
3
235
U
4.7E-7
3.8E-6
5E-4
3.8E-3
0.47
238
Np
1.0E-3
8.0E-3
1.0
8
1000
237
Pu
25
201
2.5E4
2E5
2.5E7
238
Pu
0.09
0.73
91
730
9.1E4
239
Pu
0.33
2.7
333
2670
3.3E5
240
Pu
151
1210
1.5E5
1.2E6
1.5E8
241
Am
5.1
41.1
5140
4.1E4
5.14E6
241
Calculating Activity vs Particle Size
1. Volume of the particle is
V = 1/6
ð
d .
3
2. Use the density of the isotope listed in this reference.
3. Mass of the particle is
M = V x density.
4. Activity of the particle is
A = M x specific activity.
Correct the activity of the particle for the oxide form if you need
that; the molecular weight of Pu
is 238, the activity of the
238
dioxide form must be reduced by the ratio of the molecular
weight of the dioxide form to the molecular weight of Pu
.
238
Multiply the calculated activity by 238/270 to get the activity of
the dioxide form.
For particles larger than about 1
ì
the aerodynamic diameter is
approximately equal to the physical diameter times the square
root of the density. The 10
ì
diameter particle in our example
would have an equivalent aerodynamic diameter of 34
ì
(10
ì
x
the square root of 11.46). This must be taken into account in air
sampling/monitoring situations.
4
4