Precision Measurements of Radioactive Decay Data

108mAg in Neutron Irradiated Silver Coins

“…It was later discouraged by discrepancies in published values. The half-life of 108m Ag has experienced a dramatic increase with time, being ^5 y in 1960 [6] with no indication how this value was obtained, (127±7) y in 1970 [7], and (418±15)y in 1992 [8]. A recent compilation adopts a value of (433 ±15) y [9].…”

A bilateral comparison between LNHB and PTB to determine the activity concentration of the same 125I solution

“…The participants agreed to use the same reference date, which was defined to be 18 February 2021, 0:00 UTC. Initially, PTB calculated all decay corrections using a half-life of 59.391(18) d taken from Schötzig and Schrader (2000). Later, the participants of the comparison agreed to use a half-life of 59.388(28) d which was taken from Bé et al (2011).…”

66Ga: a standard for high-energy calibration of Ge detectors

“…The first group comprises studies for which those efficiencies were determined by using (n,γ) reactions or (p,γ) resonances (Boydell [18], Gehrke [20], Hautala [21], Meyer [17]) or by using 88 Rb (17.8 min) (to 3218 keV) and 49 Ca (8.7 min) (to 4072 keV) radioactive sources (Stewart [22]). The other group is made up of studies which relied either on linear extrapolations of the efficiency on a log-log plot (Camp et al [2]), or on Monte Carlo calculations (Schötzig et al [24]). We consider less reliable (probably affected by systematic errors) the emission probabilities from this second group.…”

“…We consider less reliable (probably affected by systematic errors) the emission probabilities from this second group. Consequently, we included in our averages the data from all independent measurements except that of Schötzig et al [24] for energies below 2598 keV, but only values from the first group above this energy. All data from Schötzig et al were omitted because the calibration sources they used, and hence the extent to which their calibration relied upon Monte Carlo calculations, was not known.…”

“…Consequently, one must calibrate the efficiency of a Ge detector throughout the energy range of interest. There are several commercially available radioactive sources that are commonly used for calibrating Ge detectors, such as 22 Na, 24 Na, 54 Mn, 56 Co, 57 Co, 60 Co, 88 Y, 133 Ba, 137 Cs, 152 Eu, 154 Eu, 203 Hg, 207 Bi, 228 Th and 241 Am and, for these, the γ-ray emission probabilities for the strongest lines are known with a precision of ≈1% or better [1]. Their energies, however, cover only the limited range of 14-3500 keV.…”