Gamma-spectra recorded on 03/06/2019, 24/06/2019, and 05/08/2019 analysed for identifyiing isotopes produced and estimating their activities. The spectra are shown in attached pictures with the identified peaks labelled.
Ta179 activity given here was calculated by analysing the 61 keV peak assuming that this peak would be dominated by X-rays from Hf175 and and Ta179 (as these isotopes have at least 3 orders of magnitude larger activity than any other isotope). With that assumption, and by using the value for Hf175 activity (1.12E+04 on 5 Aug) that was calculated using its gamma peaks, the value of Ta179 activity on 5 Aug was estimated to be 1.81E+04 kBq.
A summary of most active isotopes at the time of shipment (around 24 Dec 2019) is shown in table below:
| |
|
73 d since irr |
|
7 mnths since irr |
| Isotope |
halflife (d) |
Activity on 05 Aug (kBq) |
error (kBq) |
Activity on 24Dec (kBq) |
| 179Ta |
664.3 |
1.81E+04 |
>200 |
1.55E+04 |
| 177Ta |
56.56 |
undetermined |
|
|
| 175Hf |
70 |
1.12E+04 |
14.16 |
2.80E+03 |
| 179Hf |
25.05 |
1.45E+01 |
0.91 |
3.01E-01 |
| 181Hf |
42.39 |
1.68E+01 |
0.97 |
1.71E+00 |
| 172Lu |
6.7 |
4.61E+00 |
0.50 |
2.36E-06 |
| 173Lu |
485.45 |
3.55E+01 |
6.06 |
2.90E+01 |
| 174Lu |
142 |
undetermined |
|
|
| 177Lu |
6.65 |
undetermined |
|
|
| 88Zr |
83.4 |
5.04E+00 |
1.04 |
1.57E+00 |
| 88Y |
106.63 |
6.90E-01 |
0.18 |
2.78E-01 |
| 95Nb |
34.99 |
5.11E+00 |
0.40 |
3.19E-01 |
| 57Co |
271.74 |
1.23E+01 |
1.78 |
8.57E+00 |
| 58Co |
70.86 |
7.32E-01 |
0.25 |
1.86E-01 |
| 65Zn |
243.93 |
5.71E+00 |
0.69 |
3.84E+00 |
| 54Mn |
312.2 |
2.63E+00 |
0.30 |
1.93E+00 |
| Total |
|
2.94E+04 |
|
1.83E+04 |
|