Linear ion trap for second order Doppler shift reduction in frequency standard applications

摘要

A novel linear ion trap is designed and being tested which permits storage of a large number of ions with reduced susceptibility to the second-order Doppler effect caused by the RF confining fields. This trap should store about 20 times the number of ions storable by a conventional RF trap, with no corresponding increase in second-order Doppler shift from the confining field. In addition the sensitivity of this shift to trapping parameters, i.e. RF voltage, RF frequency, and trap size, is greatly reduced. Mercury ions and xenon ions are trapped in the presence of helium buffer gas. Trap times as long as 2*10/sup 3/ s have been measured.