Investigation of the /sup 203/ /sup 205/Tl level schemes after (n,n'gamma) reactions at 2. 75 MeV

Some 259 gamma-lines have been observed with Ge(Li) detectors from (/sup 203/ /sup 205/)Tl(n,n'gamma) reactions with 2.75 MeV neutrons using (/sup nat/)Tl and enriched (/sup 203/)Tl samples. The different gamma lines could be attributed unambiguously to the (/sup 203/)Tl and (/sup 205/)Tl isotopes. It was possible to assign only 60 and 54 transitions to the known level schemes of (/sup 203/)Tl and (/sup 205/)Tl, respectively. From these facts it can be concluded that the low spin members in (/sup 203/ /sup 205/) Tl between 1.5 and 2.7 MeV are only partially known. The decay of a 5/2/sup -/ level at 2623.1 keV in (205)Tl was identified and the corresponding transition energies have been measured. With these results isomer shifts of general gamma lines corresponding to the decay of the same 5/2/sup -/ level in muonic (/sup 205/)Tl were determined.