String-guided fast transport system and photoactivation of short-lived isomers 79mBr and 77mSe by 60Co γ-ray irradiation

A compact string-guided transport (SGT) system for samples irradiated by intense 60Co γ-rays has been developed for the study of resonance photoactivation of short-lived isomers. The path length from the irradiation port to the measuring port was 12.5 m and the transport time was within 3–4 s for samples up to 90 g. Results of half-life measurements of 79mBr and 77mSe were 5.06±0.44 and 17.4±0.8 s, respectively. The integral cross-sections of 79mBr and 77mSe were determined as 169±27 and 937±99 μb keV, respectively, on the basis of the 115mIn cross section.