ANSTO's next Distinguished Lecture series topic will be on the use of Accelerator Mass Spectrometry to study the physics of the universe.
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| Radioactive species, on the other hand, produced either by astrophysical or cosmogenic processes provide an additional time information on a scale commensurate with their lifetimes. Photo credit: Hopkins 2012 |
The stable elements known to us in nature were made in stars over the whole history of our Galaxy.
In a talk titled 'Accelerator mass spectrometry enters astrophysics and geochemistry', Professor Michael Paul from the Racah Institute of Physics at Hebrew University in Israel will be the special guest of our Lucas Heights campus to discuss how Accelerator Mass Spectrometry (AMS) has entered the field of astrophysics and the potentially great impact it will have on our view of the universe.
To be held on 15 August at 11am in the AINSE theatre near the ANSTO cafeteria, this free lecture offers an opportunity for the public to hear from a leading international scientist on astrophysics and geochemistry.
ANSTO's Distinguished Lectures are a series of science talks given by leading thinkers from around the world.
Delivered as 40 minute presentations, the lecture series offers insights into some of the latest scientific breakthroughs.
Lecture overview:
Radioactive species, on the other hand, produced either by astrophysical or cosmogenic processes provide an additional time information on a scale commensurate with their lifetimes.
So-called “short-lived radioactivities”, with lifetimes compatible with Galactic evolution, are indeed playing a major role in the study of the Early Solar System and planetary formation.
This family of nuclides, including 26Al, 60Fe, 244Pu to name a few, is in fact the same as that detected at ultra-high sensitivity by AMS.
Fields such as astrophysics and geochemistry have thus recently been added to the vast panoply of disciplines investigated via AMS, with new and substantial impacts.
The 44Ti nuclide is an example of live radioactivity detected by gamma astronomy in the Cassiopeia A supernova remmant and production by the 4He + 40Ca nuclear fusion reaction, responsible for 44Ti synthesis in the supernova, was studied via AMS in the laboratory, showing a larger yield than expected.
The half-life of 146Sm, a nuclide now extinct in the Solar System, was measured via AMS and its value found significantly smaller (68 million years) than previously adopted. 146Sm serves as a clock in the chronology of silicate-mantle differentiation events in planets such as Earth, Moon and Mars and the shorter half-life shrinks our estimate of the time span of these events.
The chronology of astrophysical p-process events, a class of nucleosynthesis producing proton-rich nuclides, is also shortened relative to the Early Solar System formation.