Atomic beam resonance apparatus with six-pole magnets for radioactive isotopes

The construction of an atomic beam resonance apparatus with focusing six-pole magnets for measurements of spins and magnetic moments of radioactive nuclei is reported. The main features are similar to those of the apparatus of Hamilton, Lemonick, and Pipkin^†. The principles of the design and of maximizing the intensity are discussed. The effective solid angle, averaged over the velocity distribution of the beam, has been calculated to be about 3 × 10⁻⁴ steradians in a typical case, which is one order of magnitude larger than can be obtained by the conventional method. The apparatus has been used for measurements on four radioactive bismuth isotopes, which will be reported elsewhere.