GRETINA is a new type of gamma-ray detector to study the structure and properties of atomic nuclei. It is built from large crystals of hyper-pure germanium and will be the first detector to use the recently developed concept of gamma-ray energy tracking. GRETINA consists of 30 highly segmented coaxial germanium crystals. Each crystal is segmented into 36 electrically isolated elements and three crystals are combined in a single cryostat to form a triple-crystal module. There will be 10 modules in total. The modules are designed to fit a close-packed spherical geometry that will cover one quarter of a sphere. GRETINA is the first stage of the full Gamma-Ray Energy Tracking Array (GRETA).
At the DOE request the Gamma-ray Tracking Coordinating Committee wrote a report entitled a National Plan for Development of Gamma-ray Tracking Detectors in Nuclear Science. Many of the recommendation have been funded by DOE. The current status of the GRETINA project is described in the October 2006 Newsletter #5 which also contains links to earlier work.