Lifetime of the 473-kev Level inTm169

The lifetime of the 473-kev level in ${\mathrm{Tm}}^{169}$ has been investigated by means of an intermediate-image beta-ray spectrometer which was arranged for observing beta-gamma coincidences with a fast-slow coincidence system. From the distribution of delayed coincidences between 94-kev $L$-conversion electrons and $K$-capture x-rays, an upper limit for the half-life of the 473-kev level of 3×${10}^{-9\mathrm{}}$ sec is assigned. It is concluded that the rotational interpretation for this level is most likely the correct one.