The 8$\pi$ Spectrometer: A Detector Array for Decay Spectroscopy

The 8$\pi$ spectrometer, an array of 20 Compton-suppressed HPGe detectors arranged in a regular icosahedral geometry, was originally designed for $\gamma$-ray coincidence spectroscopy following heavy-ion reactions. At TRIUMF/ISAC-I, the 8$\pi$ has been recommissioned for studies of rare radioactive decays. The symmetry of the array virtually eliminates the effects of $\gamma-\gamma$ angular correlations when the integrated array is used in coincidence spectroscopy. When $\gamma-\gamma$ coincidences are analyzed by the five possible angles between detector pairs, however, rich angular correlation information may be extracted. Results from angular correlation decay studies with the 8$\pi$ will be presented and implications for high-granualarity detector arrays will be discussed.