ELECTRON CONVERSION SPECTRA FOR NEUTRON-DEFICIENT LUTETIUM ISOTOPES AT 1000 to 3500 kev

Conversion lines at 1 Mev and over were studied with a triple focusing BETA spectrometer, using the lutetium fraction from a tantalum target. The small coincidence background enabled measurements of very weak lines. The conversion electron spectrum for Lu/sup 172/ was plotted and five new lines were found. The lines correspond to a half life of 6 days and obviously belong to Lu/ sup 172/. For Lu/sup 171/ the half life was 8.3 plus or minus 0.2 days. The electron conversion spectrum for Lu/sup 169,170/ of 1000 kev and over are tabulated. The positron spectrum at energies over 450 kev showed two components: 2445 plus or minus 20 kev with a half life of 48 plus or minus 3 hr, which belongs to Lu/sup 170/; and 1250 plus or minus 30 kev with a half life of 34 plus or minus 4 hr, belonging to Lu/sup 169/. The ratio of S/sub 1250//S/sub 2445/ intensities is 3 3.6 plus or minus 1.5. (R.V.J.)