SAIP 2011

Developing a laser ionization test bench for radioactive beams

14 Jul 2011, 17:00

2h

Asteria

Poster Presentation Track B - Nuclear, Particle and Radiation Physics Poster2

Speaker

Mr Lucky Makhathini (University of Zululand, stellenbosch and iThemba labs)

Description

Nuclear reactions employed in the production of neutron-rich radioactive beams often produce many species simultaneously. To extract these beams, they must not only be ionized, but ionized selectively, so that only the desired species is extracted. We are developing the laser resonant ionization technique to fulfil these requirements. The method makes use of high power pulsed lasers, making it possible to assume that the ionization probability of atoms entering the laser beam zone will be close to 100%. A test setup-is being developed to ionize stable atoms. In our test bench, a stream of atoms is produced by evaporation. Atoms in the stream are ionized by lasers and transported to an ion detector with the assistance of an electric field. Ionization can be either non-resonant through a continuum of levels or resonant through excitation of an auto-ionizing state. For efficient atom ionization the transition must be saturated at all excitation stages. The condition of saturation means 100% probability of excitation of all atoms in the laser radiation zone in the time shorter than the life time of the level being excited. The lasers that are employed are the excimer laser and dye laser. The excimer laser is used to pump the dye laser and the dye laser is used to tune the wavelength. Instruments such as Fabry-Perot interferometers and diffraction gratings are used to select the wavelength required. The laser beam for ionization is directed to the chamber by means of mirrors and lenses. Separation of ion makes it possible to obtain individual spectra of each ion without the use of mass separator.