Eur. Phys. J. A (2011) 47: 96
https://doi.org/10.1140/epja/i2011-11096-1

Regular Article - Experimental Physics

Elastic alpha-particle resonances as evidence of clustering at high excitation in ⁴⁰Ca

¹ Department of Physics, Åbo Akademi, FIN-20500, Turku, Finland
² Russian Research Center “Kurchatov”, Moscow, Russia
³ Cyclotron Institute, Texas A&M University, College Station, TX, USA
⁴ Department of Physics, Florida State University, Tallahassee, FL, USA
⁵ Joint Institute for Nuclear Research, Dubna, Russia
⁶ Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania, Italy
⁷ Dipartimento di Fisica ed Astronomia, Università di Catania, Catania, Italy
⁸ Department of Physics, University of Jyväskylä, Jyväskylä, Finland

^* e-mail: mnorrby@abo.fi

Received: 9 May 2011
Revised: 12 July 2011
Accepted: 18 July 2011
Published online: 22 August 2011

Abstract

The elastic-scattering reaction ³⁶Ar + α was studied using the Thick Target Inverse Kinematics technique. Data were taken at a beam energy of 150 MeV in a reaction chamber filled with ⁴He gas, corresponding to the excitation region of 12–20 MeV in ⁴⁰Ca. Using a simplified R -matrix method of analysis energies, widths and spin assignments were obtained for 137 resonances. The structure is discussed within the concept of α-cluster structure in the quasi-continuum of ⁴⁰Ca and is compared to other nuclei in the same mass region.