Physical Review C
Knockout of α particles by 156-MeV protons from ⁶Li, ²⁴Mg, ²⁸Si, ⁴⁰Ca, ¹⁴⁰Ce, and ²³²Th has been used to investigate the A dependence of α clustering in nuclei. Protons and α particles were detected in coincidence under conditions of quasifree scattering. Corresponding reaction cross sections were measured. Cross sections for ²⁴Mg and ⁴⁰Ca were found to be about 2 orders of magnitude lower than for ⁶Li. The cross section for ²⁸Si was found to be about 3 times lower than that for ²⁴Mg and ⁴⁰Ca. Upper limits of the integrated cross sections for ¹⁴⁰Ce and ²³²U are still compatible with a A^(2/3) dependence of the α knockout process.
D. Bachelier, M. Bernas, Oleksa-Myron Bilaniuk, J. L. Boyard, J. C. Jourdain, and P. Radvanyi.
"Quasifree (p,pα) Scattering On ⁶Li, ²⁴Mg, ²⁸Si, ⁴⁰Ca, ¹⁴⁰Ce, And ²³²Th At 156 MeV".
Physical Review C.