Kunihiko Nakayama

Photoionization polarization spectroscopy of complex atoms

An improved method for the angular momentum measurement of autoionizing levels of complex atoms based on photoionization polarization spectroscopy is reported. In this method, a variation of the ion yield is measured as a function of the combination of the polarizations of the lasers used to excite the autoionizing level through a ladder of intermediate resonant states. Here, eight combinations of different polarizations in three lasers are used, which include not only circular but also linear polarizations. It has been confirmed that the angular momentum of the autoionizing level can be determined uniquely by relative ion-yield measurements for any combination of angular momenta of the levels of the excitation ladders by choosing appropriate intensities of the lasers.

Remote detector of alpha-ray using ultraviolet ray emitted by nitrogen in air

Alpha Camera was developed that can identify 1.5-kBq alpha emitter in 30-sec from 1-m away. The alpha camera equips mirror optics so that the alpha-induced ultraviolet lights are transferred while gamma-ray backgrounds are removed.