Total absorption study of the $\beta$ decay of ${}^{102,104,105}$Tc

The $\beta$-feeding probabilities for three important contributors to the decay heat in nuclear reactors, namely ${}^{102,104,105}$Tc, have been measured using the total absorption spectroscopy technique. For the measurements, sources of very high isobaric purity have been obtained using a Penning trap (JYFLTRAP). A detailed description of the data analysis is given and the results are compared with high-resolution measurements and theoretical calculations.

Figure 1

Total and photopeak gamma detection efficiency of the TAGS setup (results of Monte Carlo simulations for monoenergetic gamma rays).

Figure 2

Mass scan obtained with the Penning trap for $A=105$. During the measurements the frequency in the trap is set for the isotope of interest.

Figure 3

(a) Comparison of reconstructed spectrum after analysis with experimental data, including the contaminants, for ${}^{104}\mathrm{Tc}$. The contribution of the contaminants is also presented. (b) Comparison of the $\beta$-feeding distribution with that derived from the high-resolution measurements (Ref. [16]).

Figure 4

Comparison of reconstructed spectrum after analysis with experimental substracted data, free of contaminants, for ${}^{104}\mathrm{Tc}$.

Figure 5

(a) Comparison of reconstructed spectrum after analysis with experimental data for the decay of ${}^{105}\mathrm{Tc}$. The contribution of the contaminants is also presented. (b) $\beta$-feeding distribution obtained from analysis compared with the one from high-resolution measurements.

Figure 6

Decay chain of mass 102 relevant to the present experiment.

Figure 7

Mass scan for $A=102$.

Figure 8

Plot of the ${\chi }^2$ values obtained using different ${}^{102}\mathrm{Tc}$ and ${}^{102}\mathrm{Ru}$ ground-state feedings [see Eq. (8) for the ${\chi }^2$ definition].

Figure 9

(a) Comparison of reconstructed and experimental data including contaminants for the decay of ${}^{102}\mathrm{Tc}$. The contribution of the contaminants is also presented (dotted line). (b) $\beta$-feeding distribution obtained from experiment compared with high-resolution measurements.

Figure 10

Comparison of calculated $\gamma$ decay-heat component with data of Tobias [23] after an instantaneous fission event in ${}^{239}\mathrm{Pu}$ without and with the inclusion of ${}^{104}\mathrm{Tc}$ and ${}^{105}\mathrm{Tc}$ TAGS measurements. The individual contributions of the ${}^{104}\mathrm{Tc}$ and ${}^{105}\mathrm{Tc}$ decays are also presented.

Figure 11

Comparison of calculated $\beta$ decay-heat component with data of Tobias compilation [23] after instantaneous fission event in ${}^{239}\mathrm{Pu}$. The individual contributions of the ${}^{104}\mathrm{Tc}$ and ${}^{105}\mathrm{Tc}$ decays are also presented.

Figure 12

Comparison of calculated $\gamma$ decay-heat component with data of Tobias [23] after an instantaneous fission event in ${}^{235}\mathrm{U}$ without and with the inclusion of ${}^{104}\mathrm{Tc}$ and ${}^{105}\mathrm{Tc}$ TAGS measurements.

Figure 13

Comparison of calculated $\beta$ decay-heat component with data of Tobias compilation [23] after instantaneous fission event in ${}^{235}\mathrm{U}$.

Figure 14

Comparison of TAGS $\beta$-strength distribution for the decay of ${}^{104}\mathrm{Tc}$ with results from high-resolution measurements and calculations using gross theory.

Figure 15

Accumulated strength distributions for the decay of ${}^{104}\mathrm{Tc}$.

Figure 16

Comparison of deduced $\beta$-strength distribution for ${}^{105}\mathrm{Tc}$ with high-resolution results and with predictions of gross theory.

Figure 17

Accumulated strength distributions for ${}^{105}\mathrm{Tc}$ decay.

Figure 18

Deduced $\beta$-strength distribution from the TAGS measurement for the $\beta$-decay of ${}^{102}\mathrm{Tc}$. A comparison with high-resolution measurements and calculations using gross theory is also given.

Figure 19

Accumulated strength distributions for the decay of ${}^{102}\mathrm{Tc}$.

Figure 20

Gamow-Teller strength distributions for the decay of ${}^{102}\mathrm{Tc}$ obtained within the complex excited VAMPIR calculations compared with TAGS strength results.

Figure 21

Gamow-Teller accumulated strength distributions for the decay of ${}^{102}\mathrm{Tc}$ obtained within the complex excited VAMPIR calculations compared with TAGS strength results.

Figure 22

Gamow-Teller strength distributions for the decay of ${}^{104}\mathrm{Tc}$ obtained within the complex excited VAMPIR compared with TAGS strength results.

Figure 23

Gamow-Teller accumulated strength distributions for the decay of ${}^{104}\mathrm{Tc}$ obtained within the complex excited VAMPIR compared with TAGS strength results.