Eur. Phys. J. D 45, 81-86 (2007)
https://doi.org/10.1140/epjd/e2007-00135-4

Startup of superheavy element chemistry at RIKEN

¹ Nishina Center for Accelerator Based Science, RIKEN, Wako, 351-0198, Saitama, Japan
² Department of Physics, Saitama University, Sakura, 338-8570, Saitama, Japan
³ Graduate School of Science, Osaka University, Toyonaka, 560-0043, Osaka, Japan
⁴ Department of Physics, Tohoku University, Aoba, 980-8578, Sendai, Japan
⁵ Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, 319-1195, Ibaraki, Japan

Corresponding author: ^a haba@riken.jp

Received: 30 December 2006
Revised: 1 March 2007
Published online: 28 March 2007

Abstract

A review is given on the startup of the superheavy element (SHE) chemistry at RIKEN. A gas-jet transport system for the SHE chemistry has been coupled to the gas-filled recoil ion separator GARIS at the RIKEN Linear Accelerator. The performance of the system was appraised using ²⁰⁶Fr and ²⁴⁵Fm produced in the ¹⁶⁹Tm (⁴⁰Ar, 3n) ²⁰⁶Fr and ²⁰⁸Pb (⁴⁰Ar, 3n) ²⁴⁵Fm reactions, respectively. The α particles of ²⁰⁶Fr and ²⁴⁵Fm separated with GARIS and transported by the gas-jet were identified with a rotating wheel system for α spectrometry under desired low background condition. The high gas-jet efficiencies over 80% were independent of the beam intensities up to 2 particle μA. A gas-jet coupled target system for the production of SHEs was also installed on the beam line of the RIKEN K70 AVF cyclotron. The gas-jet transport of ²⁵⁵No and ²⁶¹Rf produced in the ²³⁸U (²²Ne, 5n) ²⁵⁵No and ²⁴⁸Cm (¹⁸O, 5n) ²⁶¹Rf reactions, respectively, was conducted for the future chemical studies of ²⁶⁵Sg via the ²⁴⁸Cm (²²Ne, 5n) ²⁶⁵Sg reaction.