Decay properties of SHE

Koji Morimoto

RIKEN, Nishina-Center, Japan

From 2000, we performed an experiment to synthesize superheavy element higher  than Z=108 (Hs) by using a cold fusion reaction with a gas-filled recoil ion separator (GARIS) at RIKEN Nishina-Center.  The isotopes studied were ^263,264,265Hs, ²⁷¹Ds, ²⁷²Rg, ²⁷⁷Cn and 278-113.  In this talk, in particular, our recent results about Hs and Cn will be discussed.  The production and decay properties of ^263,264,265Hs ware investigated by using the ²⁰⁸Pb(⁵⁸Fe,n)²⁶⁵Hs, ²⁰⁸Pb(⁵⁸Fe,2n)²⁶⁴Hs, ²⁰⁷Pb(⁵⁸Fe,n)²⁶⁴Hs, ²⁰⁶Pb(⁵⁸Fe,n)²⁶³Hs, ²⁰⁸Pb(⁵⁶Fe,n)²⁶³Hs reactions.  And the production and decay property of an isotope of the 112th element, ²⁷⁷Cn, was investigated by using the ²⁰⁸Pb(⁷⁰Zn,n)²⁷⁷Cn.  We observed one decay chain due to ²⁷⁷Cn and measured excitation function.  And in order to increase the number of statistics of the 278-113 decay property, we are continuing to produce more decay chains.  If we have new results about 278-113 at that time, the results will be discussed. Future plans of our research will be also shown.