A consortium of scientists from the national laboratories and many universities designed and built Gammasphere. The project was coordinated by scientists at Lawrence Berkeley National Laboratory, and the device first assembled there. It consists of 110 large volume, high purity germanium detectors, each in a BGO compton suppression shield.
The device is especially powerful for collecting gamma ray data following the fusion of heavy-ions, when multiplicities are high and Doppler shifts large. It has high granularity, which allows many gamma rays to be measured simultaneously, and permits precise correction for Doppler shifts. It has a photopeak efficiency for 1.3 MeV gamma-rays of 10%. As such, Gammasphere is the worlds most powerful spectrometer for nuclear structure research, rivalled only by Euroball.
Gammasphere was comissioned at the 88" cyclotron at LBNL in December 1995. The operation team at LBNL, led by project manager I Yang Lee and assisted by Augusto O. Macchiavelli and Randy McLeod, worked with many scientists from around the world to conduct a large number of experiments, mainly to study nuclei at high rotational frequencies. These experiments have involved Gammasphere as a standalone device, and operated in conjunction with a wide variety of auxiliary detectors.
GAMMASPHERE moved from LBNL to ANL in the fall of 1997, and was placed in front of the FMA fragment mass analyzer. The move was aimed at refocussing the research towards nuclei far from stability. This science is discussed in the "science case".
A popular article about GAMMASPHERE appeared in LOGOS in December of 1998 and we also have a GammaSphere on-line Booklet.