Seaborgium

Author: Robert Husted, Mollie Boorman

In June 1974, members of the Joint Institute for Nuclear Research in Dubna, U.S.S.R., reported their discovery of Element 106, which they reported to have synthesized. Glenn Seaborg was part of this group, and the element was named in his honor.

In September 1974, workers of the Lawrence Berkeley and Livermore Laboratories also claimed creation Element 106 "without any scientific doubt." The LBL and LLL Group used the Super HILAC to accelerate ¹⁸O ions onto a ²⁴⁹Cf target.

Element 106 was created by the reaction ²⁴⁹Cf(18O, 4N)²⁶³X, which decayed by alpha emission to rutherfordium, and then by alpha emission to nobelium, which in turn further decayed by alpha between daughter and granddaughter. The element so identified had alpha energies of 9.06 and 9.25 MeV with a half-life of 0.9 +/- 0.2 s.

At Dubna, 280-MeV ions of ⁵⁴Cr from the 310-cm cyclotron were used to strike targets of ²⁰⁶Pb, ²⁰⁷Pb, and ²⁰⁸Pb, in separate runs. Foils exposed to a rotating target disc were used to detect spontaneous fission activities. The foils were etched and examined microscopically to detect the number of fission tracks and the half-life of the fission activity. Other experiments were made to aid in confirmation of the discovery.