Determination of Sulfur and Copper Profile with nuclear reactions

The concentration and depth profile of Cu and S in patinna samples have been determined by using Nuclear Reaction Analysis (NRA) and Rutherford Backscattering Spectroscopy (RBS). For the NRA the differential cross section was mesaured for the 1327 keV 7-ray deexciting the third excited state to the ground state of 6 3Cu through the reaction 63Cu(p,p'7), as well as, for the 2230 keV γ-ray deexciting the first excited state to the ground state through the resonant reaction 32S(p,p'7). The mesaurements of both excitation functions were performed in the energy range 3.0 - 3.7 MeV in 20 keV steps and at an angle of 125°.

REEXAMINATION OF ASTROPHYSICAL RESONANCE-REACTION-RATE EQUATIONS FOR AN ISOLATED, NARROW RESONANCE

The well-known astrophysical resonant-reaction-rate (RRR) equations for an isolated narrow resonance induced by the charged particles have been reexamined. The validity of those assumptions used in deriving the classical analytic equations has been checked, and found that these analytic equations only hold for certain circumstances. It shows the customary definition of "narrow" is inappropriate or ambiguous in some sense, and it awakes us not to use those analytic equations without caution. As a suggestion, it is better to use the broad-resonance equation to calculate the RRR numerically even for a narrow resonance of a few keV width. The present conclusion may influence some work in which the classical narrow-resonant equations were used for calculating the RRRs, especially at low stellar temperatures for those previously defined "narrow" resonances.