Experimental Techniques in Study of Giant Resonances: Magnetic Spectrometers

Abstract

Progress in nuclear physics and development of magnetic spectrometers are inextricably linked. Research problems in nuclear physics relate to the properties of the nuclei, their internal structures, associated nuclear reactions, and their applications. A nucleus is a many-body system consisting of protons and neutrons that bind together via the strong nuclear forces. If the interactions between the constituents in a nucleus are known, then the microscopic structure could essentially be well described. However, the actual situation is not so simple because the many-body problem cannot be solved exactly, and an exact solution exists only for two-body and three-body systems. Thus, all theories to treat nuclei need a model assumption. The validity of the model should be checked by experimental examinations. In this respect, the structure and properties of excited states of the nucleus can be investigated via inelastic-scattering or particle-transfer experiments followed by gamma or particle decay. These results can then be compared with the model predictions. To study these reactions with high energy resolution, magnetic spectrometers have been developed. In this chapter, the author recounts a short history of the development of magnetic spectrometers for studies of charged-particle reactions. As an example, the author presents the magnetic spectrometer Grand Raiden, which has been installed at the Research Center for Nuclear Physics (RCNP), and discusses some important ion-optical properties necessary for magnetic spectrometers used for studies in nuclear physics. In addition, the author describes some typical experimental results and future prospects.