1970

Dubnium

• The Soviets bombarded americium-243
• with neon-22 ions and looked for
• a new alpha emission energy
• for an isotope of element 105,
• but they figured it was obscured
• by emissions from the decay of uranium
• synthesized from lead impurities
• in the americium target.
• So they began to look
• for a new half-life and found one,
• around two seconds,
• which they said was from an isotope of 105.
• *
• The Americans bombarded californium-249
• with nitrogen-15 ions and found an alpha emission
• that overlapped with the noise
• that obscured results for the Soviets.
• *
• The Soviets removed their lead impurities
• ran the experiment again,
• and found the same alpha emission
• plus decay chains involving lawrencium,
• which meant that the Soviets
• had originally found
• either dubnium-260 or dubnium-261,
• although its half-life best matched dubnium-260.

Atomic number 105

• The longest lived isotope, dubnium-268,
• decays by half in twenty-nine hours,
• leaving various isotopes by spontaneous fission
• and rutherfordium-268 by electron capture.
• The shortest lived isotope, dubnium-259,
• decays by half in half a second,
• leaving, by alpha emission, lawrencium-255,
• which, in its turn, decays.

Pattern

• All the heavy elements decay.
• If they had no other interest,
• all they would be would be
• an equal weight of lead.
• But they sparkle, they scintillate,
• they drop hints about old connections.
• Eventually, you would think,
• a pattern would emerge that might
• solve the problems of the world.