Experiments

SUPER HEAVY ELEMENTS AT GANIL

1999

   Test experiments have begun in 1996, to get a response of the complete set-up in the fusion reaction conditions. A 58Ni beam irradiated a natural tin target, with an intensity of few µAe. A rejection rate of the incident beam of 1010 was obtained.

SEARCH FOR ELEMENT 118
   After tests in 1997 and 1998, the full experimental set up was used with the system 86Kr + 121,123Sb producing Fr isotopes. The excitation functions of these systems were measured at GSI. With a beam intensity of 10 pnA, at 4.3 MeV/u, a rejection rate of the incident 86Kr beam of 2x10⁹ was obtained. The Þ decay lines of Fr isotopes and their daughters were observed by the silicon detector.
 

  The beam was then tuned to 5.27 MeV/u in order to make measurements on the 86Kr + 208Pb system for which long alpha chains attributed to element 118 were observed at Berkeley. The upper part of figure 3 represents the raw energy spectrum obtained with the implantation silicon detector. Events in anti-coincidence with the Time-Of–Flight detector are plotted on the spectrum of the lower part. Figure 4 represents events detected in the two micro channel plate detectors and in the implantation Si detector. With a total dose of 1.1x10¹⁸ ions on a 300 µg/cm2 lead targets, no Þ chain within the expected energies was observed at GANIL, in agreement with the results of SHIP.
 

2000

⁵⁴Cr + ²⁰⁸ Pb, observation of 10 decay chains of elements ^261-260SG (Z=106)