Shape and Compound Elastic Scattering ofαParticles byCa40, 5.0 to 12.5 MeV

Abstract

The differential cross section for the elastic scattering of a particles by 40 Ca has been measured at sixteen angles between 5.0 and 12.5 MeV in 10-keV intervals. Complicated structure is seen in the excitation functions which is often as fine as the experimental resolution (<10 keV). There are many closely spaced anomalies which are substantially wider than the experimental resolution. Very broad undulations are apparent in averaged differential cross-section curves for which the averaging interval is about 0.5 MeV. The averaged data are analyzed in this work. Shape elastic scattering represented by an optical model where reaction channels are either closjed or strongly inhibited does not satisfactorily describe the angular distributions at the back angles. A combination of shape and compound elastic scattering reproduces the data except at the highest energies, where reaction cross sections are becoming significant. The expression for the compound elastic contribution to the cross section is based on Hauser-Feshbach theory and statisticalmodel considerations. Values obtained for the real potential-well depth of the optical model (^-440 MeV) are consistent with results previously obtained at higher energies for the same number of nodes in the s-wave function.

Isoscalar dipole transition as a probe for asymmetric clustering

“…The α + 40 Ca cluster states in 44 Ti have also been studied by many authors [68][69][70]79,[89][90][91][92][93][94][95][96][97][98], but the situation is more complicated than the case of 20 Ne. The theoretical and experimental studies are summarized in a review paper [99], and our discussion is based on the assignment given therein.…”

α-nucleus potential for α-decay and sub-barrier fusion

“…The experimental errors in subbarrier fusion cross-section values are raised with reduction of collision energy especially in the sub-barrier region. [38,39,40,41]. This is taken into account in Eq.…”

“…The data for sub-barrier fusion cross sections for reactions α+ 40 Ca, α+ 59 Co and α+ 208 Pb was taken from [38,39,40,41].…”

“…Thus, in these reactions the values of sub-barrier fusion cross-section evaluated by different models are very close to each other, and we can make model-independent analysis of these reactions without any fitting of additional parameters. Fortunately, there are experimental data for fusion reactions α+ 40 Ca, α+ 59 Co and α+ 208 Pb [38,39,40,41].…”

Resonance spectroscopy of44Ti in the excitation energy range 9.05 to 10.28 MeV

“…The present work supplements the information obtained in these studies. In an earlier measurement [6] of 4~ in the energy range 5.0-12.5 MeV in steps of 10keV, the data was averaged over 500keV intervals and analysed using the optical model including a compound elastic component. The present measurement from 4.33 to 5.68 MeV in 5 keV steps has been analysed in terms of the R matrix theory with the aim of determining the parameters of individual resonances.…”