Los Alamos National Laboratory

Los Alamos National Laboratory

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Primordial Particle Soup

The first three chemical elements were created in the first three minutes of the big bang. Just one problem: the abundance of one of the isotopes, lithium-6, is way off from its predicted value.
May 1, 2017
OMEGA laser

Inside the target chamber for the OMEGA laser, 60 laser beams converge on a millimeter-sized target capsule to produce an imploding, nuclear-fusion supporting plasma at a temperature of more than 200 million kelvins. CREDIT: Eugene Kowaluk/University of Rochester Laboratory for Laser Energetics

In a pulse lasting less than a billionth of a second, sixty powerful lasers converge on the isotope mixture, generating a dramatic implosion.

Astronomical measurements of the primordial abundances of key isotopes produced in the big bang—three isotopes of hydrogen and two of helium—match the predictions of the big bang theory to exquisite precision. However, lithium presents a discrepancy. For its more common isotope, lithium-7, the discrepancy is manageable, but for lithium-6, observations exceed theoretical predictions by three orders of magnitude. Los Alamos plasma physicist Alex Zylstra and collaborators sought to find an explanation—perhaps an error in the relevant nuclear reaction rates—using a Department of Energy-funded advanced laser research facility. But after using the laser to heat a mixture of isotopes to big-bang temperatures, the lithium-6 conundrum remains as vexing as ever.