Lifetime measurement of Be-(2s2p(2) P-4(3/2)) using an electrostatic ion trap

The lifetime of the metastable Be-(2s2p(2) P-4(3/2)) State is measured usin g an electrostatic linear ion trap which stores keV-ion beams. Trapping usi ng electrostatic fields avoids the complication of magnetic-field-induced m ixing effects which can interfere with the measurement of the spontaneous d ecay. The result is found to be 42.07+/-0.12 mu s, which is a factor of 40 better in accuracy than the previous result determined in a heavy-ion stora ge ring. The measured lifetime is found to be 30% longer than the most rece nt theoretical value. [S1050-2947(99)01008-2].