Nuclear spins of neutron-deficient thulium isotopes

Cyclotron-produced thulium isotopes have been investigated using the atomic-beam magnetic resonance method. The spin measurements have given the following results: ¹⁵⁹Tm (9 min) , ¹⁶⁰Tm (9 min) I = 1, ¹⁶¹Tm (37 min) , ¹⁶²Tm (21.5 min) I = 1, ¹⁶⁴Tm (2 min) I = 1, ^164m Tm (5 min) I = 6 and ¹⁶⁸Tm (87 d) I = 3. An interpretation based on the Nilsson diagram for odd protons clearly indicates a systematic variation in the nuclear deformation.