Optical isotope shift and hyperfine structure measurements in preparation of the ultra-sensitive detection of krypton atoms using stepwise laser excitation and field ionization

Abstract

Within the scope of the ultra sensitive detection project the operation of the collinear fast beam laser spectroscopy apparatus and data acquisition was learned and optimized with respect to the reduction of stray laser light and the charge exchange process. Major contributions to fluctuations and drifts in the measurements have been investigated. The present data is evaluated using only the relativistically correct expressions with Microcal ORIGIN and the IMSL subroutines to perform a least squares fit to the hyperfine structure data when evaluating the hyperfine structure constants A and B. The results are the hyperfinestructure constants and isotope shifts in two transitions from the 5s'[1/2]0' , IS3 , and three transitions from the 5s[3/212' , I S5 , metastable state of krypton. The results of the isotope shift measurements in the 892 nm line of Kr have not been published previously. For the further development of the trace detection of Kr isotopes the work resulted in the construction and installation of the necessary ion-optics and detectors. Changes have been prepared as a result of the ongoing measurements. These are quasicollinear excitation of the Kr beam, avoiding optical pumping and stark shifts, shortening the distance between optical excitation and field ionization and foremost a two order of magnitude improvement of the vacuum conditions in the region the Rydberg atoms traverse by differential pumping. The overall project goal of two step resonant excitation and field ionization seems to be in close reach .