The 150Nd activation chain is not handled correctly:
150Nd (n,y) 151Nd (β⁻ 12m) 151Pm (β⁻ 28.4h) 151Sm (β⁻ 90y) 151Eu
The 151Pm halflife is instead treated as if it were 151Nd:
150Nd (n,y) 151Nd (β⁻ 12m) 151Pm (β⁻ 12m) 151Sm (β⁻ 90y) 151Eu
Use the multistage Bateman equation (wikipedia) to check the 151Pm activation levels and compare it to the two-stage calculation shown below.
With 10 g of Nd at natural abundance exposed for 10 h it appears that decay time will be dominated by 147Pm, so even an underestimate of the intermediate 151Pm levels should not be too concerning.
Activation of Nd after 10 hrs at 1.00e+8 n/cm2/s
Estimated activation only. All samples must be
evaluated by NIST Health Physics to determine if and how the sample can
be removed from the NCNR.
Sample in beam: 10.000 g of Nd
Time to decay below 5.0000e-4 μCi is 11.5 yrs.
| Isotope |
reaction |
daughter |
halflife |
0 hr |
1 hr |
24 hr |
15 days |
7.8 y |
| Nd-146 |
act |
Nd-147t |
10.98 d |
6.9608e-1 |
6.9425e-1 |
6.5350e-1 |
2.7003e-1 |
6.1453e-79 |
| Nd-146 |
b |
Pm-147 |
2.6234 y |
1.0535e-4 |
1.2630e-4 |
5.9308e-4 |
4.9559e-3 |
1.0423e-3 |
| Nd-148 |
act |
Nd-149t |
1.728 h |
1.5441e+1 |
1.0339e+1 |
1.0179e-3 |
2.9792e-62 |
0.0000e+0 |
| Nd-148 |
b |
Pm-149 |
53.08 h |
1.4703e+0 |
1.6162e+0 |
1.4545e+0 |
1.8080e-2 |
0.0000e+0 |
| Nd-150 |
act |
Nd-151t |
12.44 m |
7.2916e+0 |
2.5758e-1 |
1.0397e-34 |
0.0000e+0 |
0.0000e+0 |
| Nd-150 |
b |
Pm-151 |
28.40 h |
1.5371e+0 |
1.5505e+0 |
8.8553e-1 |
2.4306e-4 |
0.0000e+0 |
| Nd-150 |
b |
Sm-151 |
94.6 y |
5.9131e-5 |
5.9502e-5 |
5.9515e-5 |
5.9498e-5 |
5.6212e-5 |
| Total |
|
|
|
2.6437e+1 |
1.4458e+1 |
2.9952e+0 |
2.9337e-1 |
1.0986e-3 |
b reaction activity is slightly underestimated; it does not include decay of transients after removal from beam.
The 150Nd activation chain is not handled correctly:
The 151Pm halflife is instead treated as if it were 151Nd:
Use the multistage Bateman equation (wikipedia) to check the 151Pm activation levels and compare it to the two-stage calculation shown below.
With 10 g of Nd at natural abundance exposed for 10 h it appears that decay time will be dominated by 147Pm, so even an underestimate of the intermediate 151Pm levels should not be too concerning.
Activation of Nd after 10 hrs at 1.00e+8 n/cm2/s
Estimated activation only. All samples must be evaluated by NIST Health Physics to determine if and how the sample can be removed from the NCNR.
Sample in beam: 10.000 g of Nd
Time to decay below 5.0000e-4 μCi is 11.5 yrs.
b reaction activity is slightly underestimated; it does not include decay of transients after removal from beam.