Rotational States inTm171

The decay of ${\mathrm{Er}}^{171}$ has been investigated by means of a coincidence scintillation spectrometer. Eight gamma rays have been arranged in a level scheme with levels at 5, 118, 130, 337, and 425 kev. Spin and parity values have been assigned to most of levels. It is found that the first four levels form a rotational band in good agreement with the theoretical formula for the case $K=\frac{1}{2}$. The beta-ray spectrum has been resolved in components which fit very well into the level scheme. The beta- and gamma-ray transition probabilities are discussed. They are found to be in good agreement with the theory.