Physics department hosts workshop on new gamma-ray detector, GRETINA

On October 14 and 15, the University of Richmond’s Department of Physics is hosting a workshop on the new gamma-ray detector, GRETINA, being developed by a collaboration of scientists from Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory, Argonne National Laboratory, Michigan State University and other U.S. universities, including Richmond.

GRETINA is the first stage in the development of GRETA (which stands for Gamma Ray Energy Tracking Array). GRETA, a $50 million project will be 100 to 1000 times more powerful than the United States’ current gamma ray microscope Gammasphere. 

Set to be completed in 2010, GRETINA will rotate among the national laboratories, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory and the National Superconducting Cyclotron Laboratory at Michigan State University, allowing the world’s leading physicists to study the structure and properties of atomic nuclei.  Next weekend, scientists will meet at Richmond to determine the science and the schedule by which the detector will rotate between labs.

GRETINA is built from large crystals of hyper-pure germanium and will be the first detector to use the new technology of gamma-ray energy tracking.  It consists of 30 highly segmented coaxial germanium crystals, each of which is segmented into 36 electrically isolated elements; four crystals are combined in a single cryostate to form a quad-crystal module.  Ten such modules make up a quarter of a sphere, of which GRETA, the full-scale gamma ray microscope, will ultimately have four. GRETINA’s completion in 2010, therefore, represents a 25 percent completion of GRETA.

GRETINA is currently under construction at Lawrence Berkeley National Laboratory. Before GRETINA can travel, the detector will be fully commissioned at Berkeley Lab.  Scientists attending the meeting in Richmond want to maximize the potential for discovery and impact to physics research as it moves across the United States.  It is expected that GRETINA will move locations once every four to six months. 

When it is completed, GRETA and its first phase GRETINA, will allow physicists to look at the structure of nuclei at unprecedented levels of sensitivity, studying nuclei at extreme temperatures, angular momentum and excitation energies to learn more about their properties.

Workshop attendees will represent all of the low energy nuclear physics national laboratories as well as Yale University, Washington University and the University of Massachusetts at Lowell.  Several international representatives from the United Kingdom, Canada, Japan and Australia will also attend.

Posted October 1, 2007