[Todos] [SEMINARIOS] SEMINARIO GCIA.INV.Y APL-TANDAR 26/JUNIO/15 10:30 hs - DR. ANTON WALLNER 244PU AND 60FE ON EARTH - ARE THERE SIGNATURES OF RECENT SUPERNOVAE ?

[Graciela Mastrogiacomo]

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                            SEMINARIOS 2015
   Gerencia Investigación y Aplicaciones - TANDAR - CNEA
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Viernes 26 de junio, 10:30 Hs.
Auditorio Emma Pérez Ferreira - Edificio TANDAR


                        Dr. Anton WALLNER (*)
Department of Nuclear Physics, Research School of
                   Physics and Engineering
            The Australian National University

244Pu and 60Fe on Earth – are there signatures
                of recent supernovae?

SUMMARY
Accelerator mass spectrometry (AMS) represents a
sensitive technique for studying long-lived radionuclides
through ultra-low isotope ratio measurements. In this
talk I will highlight applications related to nuclear astrophysics:

Direct observation and detection of freshly synthesized
material from space is a powerful tool for understanding
nucleosynthesis. Here I will report on the detection of
live interstellar radionuclides trapped in terrestrial archives.
“How were the heavy elements from iron to uranium made?”
It is clear that half of these elements including all actinides
are made in a process requiring high neutron densities
(r-process). Their sites and history, however, still remain
unclear. Candidates are supernova (SN) explosions or
neutron-star mergers, the latter at least 100 times less
frequent than SN. New data using AMS suggest an
unexpected low abundance of interstellar 244Pu (t1/2=81 Myr).
Another isotope produced in SNe is 60Fe (t1/2=2.6 Myr).
A previous measurement at TU Munich of an Ocean
crust-sample showed an enhanced 60Fe signal of possibly
extraterrestrial origin - a close-by SN about 2-3 Myr ago?
We have started a similar program at the ANU resulting in
an exceptional sensitivity for 60Fe detection. I will discuss
a new approach to determine 60Fe’s disputed half-life value.
In addition, we have analyzed several deep-sea sediments,
crusts and nodules for extraterrestrial 60Fe. I will present
new data and will relate them to potential exposure of
Earth to recent SNe
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(*) El Dr. Wallner es doctor de la Universidad de Viena,
posdoc de la Universidad Técnica de Munich y actualmente
es profesor de la Universidad Nacional de Australia. Su campo
de investigación comprende la medición de datos nucleares
fundamentales para reactores de fusión y fisión nuclear,
estudio experimental de nucleosíntesis estelar y busqueda
de rastros de explosiones supernovas en la Tierra.

Web:
http://physics.anu.edu.au/people/profile.php?ID=1201&tab=available_projects
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Quedan todos cordialmente invitados !!!

10:15 hs  Cafe
10:30 hs  Inicio de Seminario

Auditorio Emma Pérez Ferreira - Edificio TANDAR
CNEA - Centro Atómico Constituyentes
Av. Gral. Paz 1499 (y Constituyentes)
6772-7065 / 7174 / 7531

Coordinadores:
Dra. Ana Gabriela Grunfeld: < mailto: grunfeld en tandar.cnea.gov.ar >
Dr. Horacio R. Corti: hrcorti en cnea.gov.ar

Secretaria:
Graciela Mastrogiacomo: < mailto: gmastro en tandar.cnea.gov.ar >

http://www.tandar.cnea.gov.ar/eventos/seminariosGIyA





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