Tilted Foils Nuclear Spin Polarization and Measurement with Coulomb Excitation

Licentiatavhandling, 2012

Developing new experimental tools is essential to expand the possibilites of probing the structure of atomic nuclei. The better the currently known properties of nuclei can be manipulated, the more information can be extracted from data collected in nuclear reaction experiments. One property that has been controlled for many years is the nuclear spin, but this has only been viable for a certain set of isotopes with restrictions on for example specific atomic excitation schemes or half-lives. This thesis will provide details on an evaluation project using thin tilted foils after the REX-ISOLDE linac at the CERN-ISOLDE experimental facility, to polarize the spin of nuclei in-flight. The nuclear polarization is then measured with a technique based on Coulomb excitation, which is a flexible and readily available experimental method at ISOLDE with the MINIBALL spectrometer. The tilted foils technique may be beneficial to polarize the nuclear spin of short-lived radioactive beams that can be difficult by other means. The only restrictions on the accelerated ions known so far to produce polarization with tilted foils are non-zero nuclear and atomic spin. The $\beta$-NMR is an alternative, more common technique for measuring nuclear spin polarization. No such setup connected to REX-ISOLDE existed at the start of the project which prompted for the Coulomb excitation method with MINIBALL. Although, a $\beta$-NMR setup is currently under construction and testing.