Measurement of the activity of the manganese-54 radionuclide in a source

Conclusions

From the results of measurement of the activity of the radionuclide Mn⁵⁴ in the source, carried out by the coincidence and 4π-counting method, the average value determined for the product P_kW_k=0.201±1.6%.

If we assume that P_k=0.9±1%, then we obtain W_k=0.223±2.6%. This value is in excellent agreement with the theoretical value of W_k=0.228 in [5] and with the experimental data obtained in [4, 6], but differs from the results obtained in [2, 7, 8] where W_k=0.262–0.280. Using the measured results of the activity of the Mn⁵⁴ nuclide by the 4π(e, x)-γ-coincidence method, it can be shown that W_k cannot assume values from 0.262 to 0.280.

Thus, in the case when the source was closed from both ends by a film with a thickness of ∼0.00005 g/cm², it was found that

$$\varepsilon _x = P_K W_K (1 - f_A ) + P_K (1 - W_K )\varepsilon _0 = 0.189,$$

((8))

from the ratios of the count rate in the coincidence channel and the γ-channel, where ε₀ is the efficiency of the 4π-counter to Auger electrons taking into account the absorption in the film and in the source.

From Eq. (8) we have P_kW_k(1−f _A )≤0.189. The relative absorption in the film in this case is ∼7%, i.e., 1>(1−f _A )>0.93 and, consequently, P_kW_k≤0.205. If we take P_k= 0.9±1%, when W_k≤0.228.