ELFT HÍRADÓ

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

Az MTA Atommagkutató Intézetének nagy előadójában
(Debrecen, Bem tér 18/c. 12. ép. III. em.)
2009. december 8-án, kedden (!) 11:00-kor

                 Peter MOHR
              (Schwäbisch Hall)
  
     Photon-induced reactions and K-isomers
     in nucleosynthesis: 180Ta, 176Lu, 186Re          

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

                                        Máté Zoltán
Abstract:

Lifetimes of K-isomers may change dramatically under stellar conditions. 
Photoexcitations of so-called intermediate states in the thermal photon 
bath couple low-K and high-K states that are otherwise decoupled because 
of the approximate conservation of the K quantum number. The relevant 
quantities for this coupling are defined and discussed for the examples 
180Ta, 176Lu, and 186Re. It is found that 180Ta is already thermalized 
under s-process conditions and may be interpreted as a "mixometer" [1]. 
The abundance ratio of the s-only nuclei 176Lu and 176Hf - interpreted as 
s-process thermometer - depends sensitively on the properties of the 
lowest intermediate state in 176Lu [2]. The low-lying isomer in 186Re has 
no significant influence on nucleosynthesis [3]. 
[1] P. Mohr, F. K"appeler, R. Gallino, Phys. Rev. C 75, 012802(R) (2007). 
[2] P. Mohr, S. Bisterzo, R. Gallino, F. K"appeler, U. Kneissl, N. 
    Winckler, Phys. Rev. C 79, 045804 (2009). 
[3] P. Mohr, Proceedings of Science PoS(NIC X)081 (2008).