ELFT HÍRADÓ

[Zoltan Mate <mate AT atomki.mta.hu>]

Az MTA Atommagkutató Intézetének előadótermében
(Debrecen, Bem tér 18/c. 12. ép. III. em.)
2012. szeptember 14-én, PÉNTEKEN 11:00-kor


            Matthias Junker
   (Laboratori Nazionali del Gran Sasso)
         
     What can be learned from 20 years
    of Underground Nuclear Astrophysics?

    
címmel előadást tart.
Az előadás előtt 10:30-tól tea, vendégeket szívesen látunk.

                                           Máté Zoltán

Kivonat:
Nuclear reactions play a key role in many astrophysical scenarios. 
Consequently, direct cross section measurements are desirable
in the thermal energy range of interest. The beam energies
involved are, however, often considerably lower than the Coulomb
barrier and  reaction cross sections are thus dominated by the
tunneling effect resulting an exponential drop of the cross
section. As a consequence direct measurements are extremely
challenging if not impossible and extrapolation of  the available
data are needed to obtain the cross section values at
astrophysical energies.

The quality of these extrapolations benefits from high quality
data at energies, where high statistics measurements are still
possible, but it proves necessary to push the energy limit as
close as possible to the energy range of interest in oder to
reduce the unavoidable uncertainties of the extrapolations.
One of the main experimental problems is the background induced
by cosmic rays in detectors used at the earth surface.
Installing an accelerator deep underground where the cosmic
rays background is reduced by several order of magnitude can
greatly improve the situation.

At the moment LUNA (Laboratory for Underground Nuclear
Astrophysics), located inside the Laboratori Nazionali del
Gran Sasso (LNGS) in Italy, is the only operative underground
accelerator worldwide. In this seminar recent studies performed
at LUNA will be used to show the most important features, 
challenges and possibilities related to Underground Nuclear
Astrophysics.