Engineering topics
Publications and source records attributed to Lee, I-Yang.
GRETINA is the most sensitive gamma-ray detector ever built for studies of the nucleus, including how the natural elements were made in stars and supernovae, and the properties of artificial superheavy elements. GRETINA, now being assembled at Berkeley Lab's 88-Inch Cyclotron, is the first stage of GRETA, the even more powerful Gamma-Ray Energy Tracking Array.
The new, neutron-deficient, superheavy element isotope {sup 285}114 was produced in {sup 48}Ca irradiations of {sup 242}Pu targets at a center-of-target beam energy of 256 MeV (E* = 50 MeV). The {alpha} decay of {sup 285}114 was followed by the sequential {alpha} decay of four daughter nuclides, {sup 281}Cn, {sup 277}Ds, {sup 273}Hs, and {sup 269}Sg. {sup 265}Rf was observed to decay by spontaneous fission. The measured {alpha}-decay Q values were compared with those from a macroscopic-microscopic nuclear mass model to give insight into superheavy element shell effects. The {sup 242}Pu({sup 48}Ca,5n){sup 285}114 cross section was 0.6{sub -0.5}{sup +0.9} pb.