[Triumf-seminars] TRIUMF Seminar today at 14:00

postmaster at admin.triumf.ca postmaster at admin.triumf.ca
Thu May 17 05:00:00 PDT 2007


Date/Time: Thu 2007-05-17 at 14:00

Location:  Auditorium          

Speaker:   Manoel Couder (University of Notre Dame)

Title:     Radiative 4He capture of astrophysical interest at Notre Dame

Abstract: Radiative captures of hydrogen and helium at low energy play a role in most of the nuclear astrophysics scenarios. For  example, 15O(alpha,gamma)19Ne is the trigger of X-ray bursts and 22Ne(alpha,gamma)26Mg which is in competition with 22Ne(alpha,n)25Mg, one of the neutron sources for the s-process. These two reactions are part of a series of measurements that are being carried out at the University of Notre Dame. Indirect methods were used to study 15O(alpha,gamma)19Ne because the intensity available in 
radioactive beam facilities is too low. 

While the study of a number of radiative 4He capture reactions involving stable beam were possible in direct kinematics, the 
very small cross section of these reactions at astrophysically interesting energies and the beam induced background limited 
the possible range of many other measurements. This justifies the development of a new facility for measuring cross 
sections of radiative 4He capture in reverse kinematics with stable beams. A 20 m long recoil mass separator (RMS) has 
been designed to be coupled to the KN accelerator of the University of Notre Dame. The goal of the RMS is to separate low 
mass (A<40), low energy (E<0.5 MeV/A) stable beam of up to 100 microA from the few reaction products emerging (delta theta
<40 mrad, deltaE/E <= 7.4 %) from a windowless 4He jet gas target.

Stimulants available 15 minutes before the talk.

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