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tope ratios have been carried out later by De Laeter et al. [24] with a Faraday Cup collector and Lee et al. [25] using ICP-MS (inductively coupled plasma mass spec- trometry). Both methods revealed $^{120}$Te abundances of 0.0918 (7)% and 0.0927 (4)%, respectively, which are in clear disagreement with the ”best value” assignment of 0.0960 (7)% by Smith et al. [23] given in the latest IU- PAC Technical Report 2003 [22]. In [24] the value from Smith et al. [23] was corrected with the above mentioned factor √ m$_{1}$/m$_{2}$ and one can calculate a value of 0.0935 (7)% from the given isotope ratios. The correction is due to a mass discrimination which occurs when using electron multipliers. The signal from light isotopes is en- hanced compared to that from heavier isotopes because the secondary electron yield at the first dynode is veloc- ity dependent [24]. The methods using Faraday cups [24] or ICP-MS [25] do already account for this. From these three values we can derive a weighted average of 0.0927 (9)% where the uncertainty is derived from the standard deviation of the measurements. We decided to use this value for our measurement instead of the ”representative isotopic composition” given in [22]. 

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Apart from the Pd samples, which were cut from 25 µ m thick foils, thin pellets 6 to 10 mm in diameter were pressed from the respective powder or granules and en- closed in thin cannings made from 15 µ m thick aluminum foil. During the irradiations the samples were sandwiched 

between 10-30 µ m thick gold foils of the same diameter. In this way the neutron flux can be determined relative to the well-known capture cross section of $^{197}$Au [21]. 

The activation measurements were carried out with the Van de Graaff accelerator operated in DC mode with a current of ≈ 100 µ A (for the Li targets) or even higher currents (up to 150 µ A) for the LiF targets. To ensure homogeneous illumination of the entire surface, the pro- ton beam was continuously wobbled across the Li target. The samples were irradiated in close contact with the Li target with average neutron intensities of (1.5–3) × 10 9 s − 1 at the position of the samples. The neutron intensity was recorded in intervals of 60 or 90 s using a $^{6}$Li-glass detector 91 cm downstream of the lithium target. With this information, fluctuations in the neutron yield could be properly considered in the later correction of the num- ber of nuclei, which decayed during the activation. 

Over the course of the present measurements, several independent activations have been carried out for each isotope with modified experimental parameters (see Ta- ble II). 

For the measurement of the induced activities two de- tector setups were available. A single high purity Ger- manium (HPGe) detector with a well defined measuring position at 76.0 ± 0.5 mm from the detector surface was used for counting the activities of the gold foils and of the $^{121}$Te, $^{131}$Ba, and $^{133}$Bam decays. The detector was shielded by 10 cm of lead and 5 mm of copper. Energy and efficiency calibrations have been carried out with a set of reference γ -sources in the energy range between 60 keV and 2000 keV (see Fig. 3). 

The small γ activities of $^{103}$Pd and $^{133}$Bag were mea- sured with a system of two HPGe Clover detectors (see Ref. [26] for more details). Each Clover detector consists 

## B. Activity measurements 

