Program Head: I-Yang Lee
GRETINA is a novel gamma-ray detector system designed to study the structure and properties of atomic nuclei. Its improved position resolution and high efficiency make it an ideal array to study exotic nuclei, especially those produced with fast beams. We believe it will open new frontiers in the understanding of those exotic nuclei that may exist only briefly in stars and supernovae.
GRETINA 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 28 highly segmented coaxial germanium crystals. Each crystal is segmented into 36 electrically isolated elements and four crystals are combined in a single cryostat to form a quad-crystal module. There will be 7 modules in total. The modules are designed to fit a close-packed spherical geometry that will cover one quarter of a sphere. GRETINA could be considered as the first stage of a full Gamma-Ray Energy Tracking Array (GRETA) which would cover the full sphere. The construction of GRETINA started in 2004 and is scheduled to be completed in 2011.