FLNR Scientific Seminar 29 June 2015, 15:30, FLNR Conference Hall

N.T. Brewer (ORNL) “Microsecond activity from α-emitters observed at the DGFRS with digital electronics and the benefit to campaigns for super-heavy element research” Abstract The “Hot Fusion Island” is formed by over 50 super heavy nuclei identified in fusion-evaporation reactions between ⁴⁸Ca beams and actinide targets. Most of these nuclei have been discovered in experiments at the Dubna Gas Filled Recoil Separator (DGFRS). These studies are now using a new highly segmented Si detector (DSSD) and digital detection system (PXI) commissioned by the ORNL-UTK team and implemented at the DGFRS. The system has robust analysis capabilities, especially for very short lived activities. A useful test for this detection system has been the measurement of Th activities from the ⁴⁸Ca+^natYb reaction studied at the DGFRS. For the first time at the DGFRS, the direct observation of α decay from ˜ 1-μs activity has been demonstrated. The figure shows ²¹⁹Th α decay chains along with other similarly short lived activities. This system also led to the observation of spontaneous fission events in the reaction of ⁴⁸Ca on ²⁴⁰Pu which were on the order of a few tens of μs. This capability may be essential for experiments at the SHE Factory at JINR for measurement of elements with Z>118. This new capability will be explained as well as the correlation methods used to find rare events.