Experimental nuclear structure information about neutron-richnuclei in the region between Pb and U is scarce. Projectilefragmentation of an U beam was applied to produce these exoticnuclei. The ions emerging from the target were separated in-flightin the fragment separator FRS and subsequently stored andelectron-cooled to the same velocity in the Experimental StorageRing ESR. Their revolution frequency in the ring was measuredcontinuously by means of Schottky mass spectrometry.
The data acquisition system, which was developed and appliedfor the first time, offered an effective handling of the largedata flow and recorded automatically the current experimentalparameters. Furthermore, it allowed for on-line inspection of therecording, thus securing the quality of the measurement. In orderto retrieve the information about the ions' circulation in thering, the raw data were subjected to a Fast Fourier Transform. Theparameters of the resulting Schottky noise power density spectrawere selected such as to optimize the frequency resolution and thesignal-to-noise ratio. By examining the performance of the newdata acquisition system suggestions for its further improvementare made.
Calibrating the acquired frequency spectra, taking intoaccount simulations of the experiment, provided the identificationof their frequency peaks. Combining the assigned mass-to-chargeratios of the identified peaks of all the analyzed spectra in acorrelation matrix yielded the mass values of the encounterednuclides. The masses of 23 different nuclides were obtained by ouranalysis, 3 of which for the first time. The newly measured masseswere compared with modern mass theories. The feasibility ofhalf-life measurements with the new data acquisition system wasstudied by determining the half-life of 233Ac88+.
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