Europe To Build State
Of The Art Laboratory To Study How Stars Evolve And Elements Are Formed In
Cosmo
(11 March 2008) One of the great
ongoing challenges of astrophysics, to find out how stars evolve and die, is to
be tackled in an ambitious European research programme.
This
will involve studying in the laboratory over 25 critical nuclear reactions
using low-energy stable beams of ions, in order to understand stellar
evolution. "This programme will enhance the ongoing effort to understand the
lifecycle of stars, together with the structure and processes of stellar
evolution," said the workshop's convenor Sotirios Harissopulos from the
National Centre of Scientific Research "Demokritos", Greece . "We also want to
try and understand what happens when stars explode and how heavy elements are
produced as a result."
Although astrophysicists have been studying these
questions for half a century, progress has been held back by the experimental
difficulties involved. But now there is the opportunity to exploit new
technology to build a major laboratory that would propel Europe to the head of
the field of stellar evolution and nucleosynthesis. "We now want to build a
state of the art facility to disentangle all these problems," said
Harissopulos.
The framework for this research programme was evaluated at
a recent workshop, "The future of stable beams in Nuclear Astrophysics",
organised by the European Science Foundation (ESF). The workshop highlighted
the urgent need to build a laboratory where state of the art instrumentation
could be hosted, at a cost of less than 10 million Euros. "Unfortunately,
leading nuclear astrophysics laboratories in Europe fulfilling these
requirements are already closed or will be closed in the near future, while
others have been "transformed" into analytical laboratories or irradiation
facilities in order to survive in a highly competitive environment, where the
demand for industrial applications has washed out many basic research
activities in the field of low-energy nuclear physics," said Harissopulos. "As
a result, a flagship facility providing intense stable beams for nuclear
astrophysics studies in Europe is missing and, hence, there is an urgent need
for Europe to create a new state-of-the art facility equipped with advanced
detection techniques."
Europe already has Radioactive Ion Beam (RIB)
facilities to study various scenarios in which nucleosynthesis occurs in
explosive stellar environments. The new planned facility based on stable ion
beams would complement these existing sites and enable a much more complete
picture of stellar evolution and nucleosynthesis to be built up.
Both
stable and unstable ion beams are powerful tools to study the process of
nucleosynthesis, in which chemical elements are created by thermonuclear
reactions, or other nuclear processes involving beams of neutrons. "By studying
these nuclear reactions, astrophysicists attempt to reconstruct the signatures
of the various nucleosynthetic processes that take place throughout the
universe, and what happens as stars are born, evolve and then die," said
Harissopulos.
There is a particular interest in what happens at the end
of a star's life, especially when this produces a supernova in a great
expanding shock wave. All these processes taken together also shed light on the
larger scale evolution of galaxies, including our own. The European project
planned by the ESF workshop could make substantial contributions on all these
fronts.
The importance of stable ion-beams in nuclear physics research
was independently documented in the recent scientific report produced by ECOS,
the European Collaboration on Stable ion-beams. ECOS has operated in the past
two years as a working group of the Nuclear Physics European Collaboration
Committee (NuPECC), which is the ESF's expert committee for nuclear science.
According to the ECOS report, "a low-energy and high-intensity stable-ion beam
facility dedicated to nuclear astrophysics is seen as vitally important to
improvement of our current understanding of stellar evolution and
nucleosynthesis. ... Such a facility, built on the earth's surface, will have
to meet demanding specifications if it is to resolve outstanding open questions
in nuclear astrophysics..." The ESF Workshop came up with ideas about how these
recommendations can be achieved in the near future.
As Harissopulos
noted, the workshop has fulfilled all the preliminary planning objectives. "The
framework of the research to be conducted in the new facility as well as the
specifications of the facility was identified. The experimental set ups and
detectors systems that need to be embedded in the facility have also been
defined. An expert committee for follow-up activities was assigned with the aim
of producing a physics-case report and a basic design study for the new
facility, as well as identifying initiatives at a European level that will lead
to creation of this facility. The expert committee has recognised the decisive
role of the ESF in promoting and supporting science initiatives."
The
ESF Workshop "The future of stable beams in Nuclear Astrophysics" took place at
the Congress Centre of the National Centre for Scientific Research
"Demokritos", Athens, Greece, from the 14th to the 15th December 2007. It was
attended by 25 scientists from 10 different European countries.
(source:
European Science Foundation)
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